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Forecasting

Forecasting is the process of making predictions based on past and present data. Later these can be compared (resolved) against what happens. For example, a company might estimate their revenue in the next year, then compare it against the actual results creating a variance actual analysis. Prediction is a similar but more general term. Forecasting might refer to specific formal statistical methods employing time series, cross-sectional or longitudinal data, or alternatively to less formal judgmental methods or the process of prediction and resolution itself. Usage can vary between areas of application: for example, in hydrology the terms "forecast" and "forecasting" are sometimes reserved for estimates of values at certain specific future times, while the term "prediction" is used for more general estimates, such as the number of times floods will occur over a long period.

Risk and uncertainty are central to forecasting and prediction; it is generally considered a good practice to indicate the degree of uncertainty attaching to forecasts. In any case, the data must be up to date in order for the forecast to be as accurate as possible. In some cases the data used to predict the variable of interest is itself forecast.[1] A forecast is not to be confused with a Budget; budgets are more specific, fixed-term financial plans used for resource allocation and control, while forecasts provide estimates of future financial performance, allowing for flexibility and adaptability to changing circumstances. Both tools are valuable in financial planning and decision-making, but they serve different functions.

Applications edit

Forecasting has applications in a wide range of fields where estimates of future conditions are useful. Depending on the field, accuracy varies significantly. If the factors that relate to what is being forecast are known and well understood and there is a significant amount of data that can be used, it is likely the final value will be close to the forecast. If this is not the case or if the actual outcome is affected by the forecasts, the reliability of the forecasts can be significantly lower.[2]

Climate change and increasing energy prices have led to the use of Egain Forecasting for buildings. This attempts to reduce the energy needed to heat the building, thus reducing the emission of greenhouse gases. Forecasting is used in customer demand planning in everyday business for manufacturing and distribution companies.

While the veracity of predictions for actual stock returns are disputed through reference to the efficient-market hypothesis, forecasting of broad economic trends is common. Such analysis is provided by both non-profit groups as well as by for-profit private institutions.[citation needed]

Forecasting foreign exchange movements is typically achieved through a combination of chart and fundamental analysis. An essential difference between chart analysis and fundamental economic analysis is that chartists study only the price action of a market, whereas fundamentalists attempt to look to the reasons behind the action.[3] Financial institutions assimilate the evidence provided by their fundamental and chartist researchers into one note to provide a final projection on the currency in question.[4]

Forecasting has also been used to predict the development of conflict situations.[5] Forecasters perform research that uses empirical results to gauge the effectiveness of certain forecasting models.[6] However research has shown that there is little difference between the accuracy of the forecasts of experts knowledgeable in the conflict situation and those by individuals who knew much less.[7] Similarly, experts in some studies argue that role thinking — standing in other people's shoes to forecast their decisions — does not contribute to the accuracy of the forecast.[8]

An important, albeit often ignored aspect of forecasting, is the relationship it holds with planning. Forecasting can be described as predicting what the future will look like, whereas planning predicts what the future should look like.[6] There is no single right forecasting method to use. Selection of a method should be based on your objectives and your conditions (data etc.).[9] A good place to find a method, is by visiting a selection tree. An example of a selection tree can be found here.[10]

Forecasting has application in many situations:

Forecasting as training, betting and futarchy edit

In several cases, the forecast is either more or less than a prediction of the future.

In Philip E. Tetlock's Superforecasting: The Art and Science of Prediction, he discusses forecasting as a method of improving the ability to make decisions. A person can become better calibrated[citation needed]i.e. having things they give 10% credence to happening 10% of the time. Or they can forecast things more confidently[citation needed] — coming to the same conclusion but earlier. Some have claimed that forecasting is a transferable skill with benefits to other areas of discussion and decision making.[citation needed]

Betting on sports or politics is another form of forecasting. Rather than being used as advice, bettors are paid based on if they predicted correctly. While decisions might be made based on these bets (forecasts), the main motivation is generally financial.

Finally, futarchy is a form of government where forecasts of the impact of government action are used to decide which actions are taken. Rather than advice, in futarchy's strongest form, the action with the best forecasted result is automatically taken.[citation needed]

Forecast improvements edit

Forecast improvement projects have been operated in a number of sectors: the National Hurricane Center's Hurricane Forecast Improvement Project (HFIP) and the Wind Forecast Improvement Project sponsored by the US Department of Energy are examples.[12] In relation to supply chain management, the Du Pont model has been used to show that an increase in forecast accuracy can generate increases in sales and reductions in inventory, operating expenses and commitment of working capital.[13]

Categories of forecasting methods edit

Qualitative vs. quantitative methods edit

Qualitative forecasting techniques are subjective, based on the opinion and judgment of consumers and experts; they are appropriate when past data are not available. They are usually applied to intermediate- or long-range decisions. Examples of qualitative forecasting methods are[citation needed] informed opinion and judgment, the Delphi method, market research, and historical life-cycle analogy.

Quantitative forecasting models are used to forecast future data as a function of past data. They are appropriate to use when past numerical data is available and when it is reasonable to assume that some of the patterns in the data are expected to continue into the future. These methods are usually applied to short- or intermediate-range decisions. Examples of quantitative forecasting methods are[citation needed] last period demand, simple and weighted N-Period moving averages, simple exponential smoothing, Poisson process model based forecasting[14] and multiplicative seasonal indexes. Previous research shows that different methods may lead to different level of forecasting accuracy. For example, GMDH neural network was found to have better forecasting performance than the classical forecasting algorithms such as Single Exponential Smooth, Double Exponential Smooth, ARIMA and back-propagation neural network.[15]

Average approach edit

In this approach, the predictions of all future values are equal to the mean of the past data. This approach can be used with any sort of data where past data is available. In time series notation:

  [16]

where   is the past data.

Although the time series notation has been used here, the average approach can also be used for cross-sectional data (when we are predicting unobserved values; values that are not included in the data set). Then, the prediction for unobserved values is the average of the observed values.

Naïve approach edit

Naïve forecasts are the most cost-effective forecasting model, and provide a benchmark against which more sophisticated models can be compared. This forecasting method is only suitable for time series data.[16] Using the naïve approach, forecasts are produced that are equal to the last observed value. This method works quite well for economic and financial time series, which often have patterns that are difficult to reliably and accurately predict.[16] If the time series is believed to have seasonality, the seasonal naïve approach may be more appropriate where the forecasts are equal to the value from last season. In time series notation:

 

Drift method edit

A variation on the naïve method is to allow the forecasts to increase or decrease over time, where the amount of change over time (called the drift) is set to be the average change seen in the historical data. So the forecast for time   is given by

  [16]

This is equivalent to drawing a line between the first and last observation, and extrapolating it into the future.

Seasonal naïve approach edit

The seasonal naïve method accounts for seasonality by setting each prediction to be equal to the last observed value of the same season. For example, the prediction value for all subsequent months of April will be equal to the previous value observed for April. The forecast for time   is[16]

 

where  =seasonal period and   is the smallest integer greater than  .

The seasonal naïve method is particularly useful for data that has a very high level of seasonality.

Deterministic approach edit

A deterministic approach is when there is no stochastic variable involved and the forecasts depend on the selected functions and parameters.[17][18] For example, given the function

 


The short term behaviour   and the is the medium-long term trend   are

 

where   are some parameters.

This approach has been proposed to simulate bursts of seemingly stochastic activity, interrupted by quieter periods. The assumption is that the presence of a strong deterministic ingredient is hidden by noise. The deterministic approach is noteworthy as it can reveal the underlying dynamical systems structure, which can be exploited for steering the dynamics into a desired regime.[17]

Time series methods edit

Time series methods use historical data as the basis of estimating future outcomes. They are based on the assumption that past demand history is a good indicator of future demand.

e.g. Box–Jenkins
Seasonal ARIMA or SARIMA or ARIMARCH,

Relational methods edit

Some forecasting methods try to identify the underlying factors that might influence the variable that is being forecast. For example, including information about climate patterns might improve the ability of a model to predict umbrella sales. Forecasting models often take account of regular seasonal variations. In addition to climate, such variations can also be due to holidays and customs: for example, one might predict that sales of college football apparel will be higher during the football season than during the off season.[19]

Several informal methods used in causal forecasting do not rely solely on the output of mathematical algorithms, but instead use the judgment of the forecaster. Some forecasts take account of past relationships between variables: if one variable has, for example, been approximately linearly related to another for a long period of time, it may be appropriate to extrapolate such a relationship into the future, without necessarily understanding the reasons for the relationship.

Causal methods include:

Quantitative forecasting models are often judged against each other by comparing their in-sample or out-of-sample mean square error, although some researchers have advised against this.[21] Different forecasting approaches have different levels of accuracy. For example, it was found in one context that GMDH has higher forecasting accuracy than traditional ARIMA.[22]

Judgmental methods edit

Judgmental forecasting methods incorporate intuitive judgement, opinions and subjective probability estimates. Judgmental forecasting is used in cases where there is a lack of historical data or during completely new and unique market conditions.[23]

Judgmental methods include:

Artificial intelligence methods edit

Often these are done today by specialized programs loosely labeled

Geometric extrapolation with error prediction edit

Can be created with 3 points of a sequence and the "moment" or "index". This type of extrapolation has 100% accuracy in predictions in a big percentage of known series database (OEIS).[24]

Other methods edit

Forecasting accuracy edit

The forecast error (also known as a residual) is the difference between the actual value and the forecast value for the corresponding period:

 

where E is the forecast error at period t, Y is the actual value at period t, and F is the forecast for period t.

A good forecasting method will yield residuals that are uncorrelated. If there are correlations between residual values, then there is information left in the residuals which should be used in computing forecasts. This can be accomplished by computing the expected value of a residual as a function of the known past residuals, and adjusting the forecast by the amount by which this expected value differs from zero.

A good forecasting method will also have zero mean. If the residuals have a mean other than zero, then the forecasts are biased and can be improved by adjusting the forecasting technique by an additive constant that equals the mean of the unadjusted residuals.

Measures of aggregate error:

Scaled-dependent errors edit

The forecast error, E, is on the same scale as the data, as such, these accuracy measures are scale-dependent and cannot be used to make comparisons between series on different scales.

Mean absolute error (MAE) or mean absolute deviation (MAD):  

Mean squared error (MSE) or mean squared prediction error (MSPE):  

Root mean squared error (RMSE):  

Average of Errors (E):  

Percentage errors edit

These are more frequently used to compare forecast performance between different data sets because they are scale-independent. However, they have the disadvantage of being extremely large or undefined if Y is close to or equal to zero.

Mean absolute percentage error (MAPE):  

Mean absolute percentage deviation (MAPD):  

Scaled errors edit

Hyndman and Koehler (2006) proposed using scaled errors as an alternative to percentage errors.

Mean absolute scaled error (MASE):  

where m=seasonal period or 1 if non-seasonal

Other measures edit

Forecast skill (SS):  

Business forecasters and practitioners sometimes use different terminology. They refer to the PMAD as the MAPE, although they compute this as a volume weighted MAPE. For more information, see Calculating demand forecast accuracy.

When comparing the accuracy of different forecasting methods on a specific data set, the measures of aggregate error are compared with each other and the method that yields the lowest error is preferred.

Training and test sets edit

When evaluating the quality of forecasts, it is invalid to look at how well a model fits the historical data; the accuracy of forecasts can only be determined by considering how well a model performs on new data that were not used when fitting the model. When choosing models, it is common to use a portion of the available data for fitting, and use the rest of the data for testing the model, as was done in the above examples.[25]

Cross-validation edit

Cross-validation is a more sophisticated version of training a test set.

For cross-sectional data, one approach to cross-validation works as follows:

  1. Select observation i for the test set, and use the remaining observations in the training set. Compute the error on the test observation.
  2. Repeat the above step for i = 1,2,..., N where N is the total number of observations.
  3. Compute the forecast accuracy measures based on the errors obtained.

This makes efficient use of the available data, as only one observation is omitted at each step

For time series data, the training set can only include observations prior to the test set. Therefore, no future observations can be used in constructing the forecast. Suppose k observations are needed to produce a reliable forecast; then the process works as follows:

  1. Starting with i=1, select the observation k + i for the test set, and use the observations at times 1, 2, ..., k+i–1 to estimate the forecasting model. Compute the error on the forecast for k+i.
  2. Repeat the above step for i = 2,...,T–k where T is the total number of observations.
  3. Compute the forecast accuracy over all errors.

This procedure is sometimes known as a "rolling forecasting origin" because the "origin" (k+i -1) at which the forecast is based rolls forward in time.[25] Further, two-step-ahead or in general p-step-ahead forecasts can be computed by first forecasting the value immediately after the training set, then using this value with the training set values to forecast two periods ahead, etc.

See also

Seasonality and cyclic behaviour edit

Seasonality edit

Seasonality is a characteristic of a time series in which the data experiences regular and predictable changes which recur every calendar year. Any predictable change or pattern in a time series that recurs or repeats over a one-year period can be said to be seasonal. It is common in many situations – such as grocery store[26] or even in a Medical Examiner's office[27]—that the demand depends on the day of the week. In such situations, the forecasting procedure calculates the seasonal index of the “season” – seven seasons, one for each day – which is the ratio of the average demand of that season (which is calculated by Moving Average or Exponential Smoothing using historical data corresponding only to that season) to the average demand across all seasons. An index higher than 1 indicates that demand is higher than average; an index less than 1 indicates that the demand is less than the average.

Cyclic behaviour edit

The cyclic behaviour of data takes place when there are regular fluctuations in the data which usually last for an interval of at least two years, and when the length of the current cycle cannot be predetermined. Cyclic behavior is not to be confused with seasonal behavior. Seasonal fluctuations follow a consistent pattern each year so the period is always known. As an example, during the Christmas period, inventories of stores tend to increase in order to prepare for Christmas shoppers. As an example of cyclic behaviour, the population of a particular natural ecosystem will exhibit cyclic behaviour when the population decreases as its natural food source decreases, and once the population is low, the food source will recover and the population will start to increase again. Cyclic data cannot be accounted for using ordinary seasonal adjustment since it is not of fixed period.

Limitations edit

Limitations pose barriers beyond which forecasting methods cannot reliably predict. There are many events and values that cannot be forecast reliably. Events such as the roll of a die or the results of the lottery cannot be forecast because they are random events and there is no significant relationship in the data. When the factors that lead to what is being forecast are not known or well understood such as in stock and foreign exchange markets forecasts are often inaccurate or wrong as there is not enough data about everything that affects these markets for the forecasts to be reliable, in addition the outcomes of the forecasts of these markets change the behavior of those involved in the market further reducing forecast accuracy.[2]

The concept of "self-destructing predictions" concerns the way in which some predictions can undermine themselves by influencing social behavior.[28] This is because "predictors are part of the social context about which they are trying to make a prediction and may influence that context in the process".[28] For example, a forecast that a large percentage of a population will become HIV infected based on existing trends may cause more people to avoid risky behavior and thus reduce the HIV infection rate, invalidating the forecast (which might have remained correct if it had not been publicly known). Or, a prediction that cybersecurity will become a major issue may cause organizations to implement more security cybersecurity measures, thus limiting the issue.

Performance limits of fluid dynamics equations edit

As proposed by Edward Lorenz in 1963, long range weather forecasts, those made at a range of two weeks or more, are impossible to definitively predict the state of the atmosphere, owing to the chaotic nature of the fluid dynamics equations involved. Extremely small errors in the initial input, such as temperatures and winds, within numerical models double every five days.[29]

See also edit

References edit

  1. ^ French, Jordan (2017). "The time traveller's CAPM". Investment Analysts Journal. 46 (2): 81–96. doi:10.1080/10293523.2016.1255469. S2CID 157962452.
  2. ^ a b Forecasting: Principles and Practice.
  3. ^ Helen Allen; Mark P. Taylor (1990). "Charts, Noise and Fundamentals in the London Foreign Exchange Market". The Economic Journal. 100 (400): 49–59. doi:10.2307/2234183. JSTOR 2234183.
  4. ^ Pound Sterling Live. "Euro Forecast from Institutional Researchers", A list of collated exchange rate forecasts encompassing technical and fundamental analysis in the foreign exchange market.
  5. ^ T. Chadefaux (2014). "Early warning signals for war in the news". Journal of Peace Research, 51(1), 5-18
  6. ^ a b J. Scott Armstrong; Kesten C. Green; Andreas Graefe (2010). (PDF). Archived from the original (PDF) on 2012-07-11. Retrieved 2012-01-23.
  7. ^ Kesten C. Greene; J. Scott Armstrong (2007). (PDF). Interfaces: 1–12. Archived from the original (PDF) on 2010-06-20. Retrieved 2011-12-29.
  8. ^ Kesten C. Green; J. Scott Armstrong (1975). "Role thinking: Standing in other people's shoes to forecast decisions in conflicts". International Journal of Forecasting. 39: 111–116. SSRN 1596623.
  9. ^ "FAQ". Forecastingprinciples.com. 1998-02-14. Retrieved 2012-08-28.
  10. ^ "Selection Tree". Forecastingprinciples.com. 1998-02-14. Retrieved 2012-08-28.
  11. ^ J. Scott Armstrong (1983). "Relative Accuracy of Judgmental and Extrapolative Methods in Forecasting Annual Earnings" (PDF). Journal of Forecasting. 2 (4): 437–447. doi:10.1002/for.3980020411. S2CID 16462529.
  12. ^ Department of Energy, The Wind Forecast Improvement Project (WFIP): A Public–Private Partnership Addressing Wind Energy Forecast Needs, published 30 October 2015, accessed 9 December 2022
  13. ^ Logility, Inc. (2016), Beyond Basic Forecasting, accessed 9 December 2022
  14. ^ Mahmud, Tahmida; Hasan, Mahmudul; Chakraborty, Anirban; Roy-Chowdhury, Amit (19 August 2016). A poisson process model for activity forecasting. 2016 IEEE International Conference on Image Processing (ICIP). IEEE. doi:10.1109/ICIP.2016.7532978.
  15. ^ Li, Rita Yi Man; Fong, Simon; Chong, Kyle Weng Sang (2017). "Forecasting the REITs and stock indices: Group Method of Data Handling Neural Network approach". Pacific Rim Property Research Journal. 23 (2): 123–160. doi:10.1080/14445921.2016.1225149. S2CID 157150897.
  16. ^ a b c d e 2.3 Some simple forecasting methods - OTexts. Retrieved 16 March 2018. {{cite book}}: |website= ignored (help)
  17. ^ a b Stoop, Ruedi; Orlando, Giuseppe; Bufalo, Michele; Della Rossa, Fabio (2022-11-18). "Exploiting deterministic features in apparently stochastic data". Scientific Reports. 12 (1): 19843. doi:10.1038/s41598-022-23212-x. hdl:11311/1233353. ISSN 2045-2322.
  18. ^ Orlando, Giuseppe; Bufalo, Michele; Stoop, Ruedi (2022-02-01). "Financial markets' deterministic aspects modeled by a low-dimensional equation". Scientific Reports. 12 (1): 1693. doi:10.1038/s41598-022-05765-z. hdl:20.500.11850/531723. ISSN 2045-2322.
  19. ^ Steven Nahmias; Tava Lennon Olsen (15 January 2015). Production and Operations Analysis: Seventh Edition. Waveland Press. ISBN 978-1-4786-2824-8.
  20. ^ Ellis, Kimberly (2008). Production Planning and Inventory Control Virginia Tech. McGraw Hill. ISBN 978-0-390-87106-0.
  21. ^ J. Scott Armstrong and Fred Collopy (1992). (PDF). International Journal of Forecasting. 8: 69–80. CiteSeerX 10.1.1.423.508. doi:10.1016/0169-2070(92)90008-w. Archived from the original (PDF) on 2012-02-06.
  22. ^ 16. Li, Rita Yi Man, Fong, S., Chong, W.S. (2017) Forecasting the REITs and stock indices: Group Method of Data Handling Neural Network approach, Pacific Rim Property Research Journal, 23(2), 1-38
  23. ^ 3.1 Introduction - OTexts. Retrieved 16 March 2018. {{cite book}}: |website= ignored (help)
  24. ^ V. Nos (2021-06-02). "Probnet: Geometric Extrapolation of Integer Sequences with error prediction". Hackage. Haskell.org. from the original on 2022-08-14. Retrieved 2022-12-06.
  25. ^ a b 2.5 Evaluating forecast accuracy | OTexts. Retrieved 2016-05-14. {{cite book}}: |website= ignored (help)
  26. ^ Erhun, F.; Tayur, S. (2003). "Enterprise-Wide Optimization of Total Landed Cost at a Grocery Retailer". Operations Research. 51 (3): 343. doi:10.1287/opre.51.3.343.14953.
  27. ^ Omalu, B. I.; Shakir, A. M.; Lindner, J. L.; Tayur, S. R. (2007). "Forecasting as an Operations Management Tool in a Medical Examiner's Office". Journal of Health Management. 9: 75–84. doi:10.1177/097206340700900105. S2CID 73325253.
  28. ^ a b Overland, Indra (2019-03-01). "The geopolitics of renewable energy: Debunking four emerging myths". Energy Research & Social Science. 49: 36–40. doi:10.1016/j.erss.2018.10.018. ISSN 2214-6296.
  29. ^ Cox, John D. (2002). Storm Watchers. John Wiley & Sons, Inc. pp. 222–224. ISBN 978-0-471-38108-2.

Sources edit

  • Armstrong, J. Scott, ed. (2001). Principles of Forecasting: A Handbook for Researchers and Practitioners. Norwell, Massachusetts: Kluwer Academic Publishers. ISBN 978-0-7923-7930-0.
  • Ellis, Kimberly (2010). Production Planning and Inventory Control. McGraw-Hill. ISBN 978-0-412-03471-8.
  • Geisser, Seymour (June 1993). Predictive Inference: An Introduction. Chapman & Hall, CRC Press. ISBN 978-0-390-87106-0.
  • Gilchrist, Warren (1976). Statistical Forecasting. London: John Wiley & Sons. ISBN 978-0-471-99403-9.
  • Hyndman, Rob J.; Koehler, Anne B. (October–December 2006). "Another look at measures of forecast accuracy" (PDF). International Journal of Forecasting. 22 (4): 679–688. CiteSeerX 10.1.1.154.9771. doi:10.1016/j.ijforecast.2006.03.001.
  • Makridakis, Spyros; Wheelwrigt, Steven; Hyndman, Rob J. (1998). Forecasting: Methods and Applications. John Wiley & Sons. ISBN 978-0-471-53233-0.
  • Malakooti, Behnam (February 2014). Operations and Production Systems with Multiple Objectives. John Wiley & Sons. ISBN 978-0-470-03732-4.
  • Kaligasidis, Angela Sasic; Taesler, Roger; Andersson, Cari; Nord, Margitta (August 2006). "Upgraded weather forecast control of building heating systems". In Fazio, Paul (ed.). Research in Building Physics and Building Engineering. Taylor & Francis, CRC Press. pp. 951–958. ISBN 978-0-415-41675-7.
  • Kress, George J.; Snyder, John (May 1994). Forecasting and Market Analysis Techniques: A Practical Approach. Quorum Books. ISBN 978-0-89930-835-7.
  • Rescher, Nicholas (1998). Predicting the Future: An Introduction to the Theory of Forecasting. State University of New York Press. ISBN 978-0-7914-3553-3.
  • Taesler, Roger (1991). "Climate and Building Energy Management". Energy and Buildings. 15 (1–2): 599–608. doi:10.1016/0378-7788(91)90028-2.
  • Turchin, Peter (2007). "Scientific Prediction in Historical Sociology: Ibn Khaldun meets Al Saud". History & Mathematics: Historical Dynamics and Development of Complex Societies. Moscow: KomKniga. pp. 9–38. ISBN 978-5-484-01002-8.
  • US patent 6098893, Berglund, Ulf Stefan & Lundberg, Bjorn Henry, "Comfort control system incorporating weather forecast data and a method for operating such a system", issued August 8, 2000 .

External links edit

  •   Media related to Prediction at Wikimedia Commons
  • Forecasting Principles: "Evidence-based forecasting"
  • International Institute of Forecasters
  • Introduction to Time series Analysis (Engineering Statistics Handbook) - A practical guide to Time series analysis and forecasting
  • Time Series Analysis
  • Global Forecasting with IFs
  • Earthquake Electromagnetic Precursor Research
  • Forecasting Science and Theory of Forecasting

forecasting, other, uses, forecast, process, making, predictions, based, past, present, data, later, these, compared, resolved, against, what, happens, example, company, might, estimate, their, revenue, next, year, then, compare, against, actual, results, crea. For other uses see Forecast Forecasting is the process of making predictions based on past and present data Later these can be compared resolved against what happens For example a company might estimate their revenue in the next year then compare it against the actual results creating a variance actual analysis Prediction is a similar but more general term Forecasting might refer to specific formal statistical methods employing time series cross sectional or longitudinal data or alternatively to less formal judgmental methods or the process of prediction and resolution itself Usage can vary between areas of application for example in hydrology the terms forecast and forecasting are sometimes reserved for estimates of values at certain specific future times while the term prediction is used for more general estimates such as the number of times floods will occur over a long period Risk and uncertainty are central to forecasting and prediction it is generally considered a good practice to indicate the degree of uncertainty attaching to forecasts In any case the data must be up to date in order for the forecast to be as accurate as possible In some cases the data used to predict the variable of interest is itself forecast 1 A forecast is not to be confused with a Budget budgets are more specific fixed term financial plans used for resource allocation and control while forecasts provide estimates of future financial performance allowing for flexibility and adaptability to changing circumstances Both tools are valuable in financial planning and decision making but they serve different functions Contents 1 Applications 2 Forecasting as training betting and futarchy 3 Forecast improvements 4 Categories of forecasting methods 4 1 Qualitative vs quantitative methods 4 2 Average approach 4 3 Naive approach 4 4 Drift method 4 5 Seasonal naive approach 4 6 Deterministic approach 4 7 Time series methods 4 8 Relational methods 4 9 Judgmental methods 4 10 Artificial intelligence methods 4 11 Geometric extrapolation with error prediction 4 12 Other methods 5 Forecasting accuracy 5 1 Scaled dependent errors 5 2 Percentage errors 5 3 Scaled errors 5 4 Other measures 5 5 Training and test sets 5 6 Cross validation 6 Seasonality and cyclic behaviour 6 1 Seasonality 6 2 Cyclic behaviour 7 Limitations 7 1 Performance limits of fluid dynamics equations 8 See also 9 References 10 Sources 11 External linksApplications editForecasting has applications in a wide range of fields where estimates of future conditions are useful Depending on the field accuracy varies significantly If the factors that relate to what is being forecast are known and well understood and there is a significant amount of data that can be used it is likely the final value will be close to the forecast If this is not the case or if the actual outcome is affected by the forecasts the reliability of the forecasts can be significantly lower 2 Climate change and increasing energy prices have led to the use of Egain Forecasting for buildings This attempts to reduce the energy needed to heat the building thus reducing the emission of greenhouse gases Forecasting is used in customer demand planning in everyday business for manufacturing and distribution companies While the veracity of predictions for actual stock returns are disputed through reference to the efficient market hypothesis forecasting of broad economic trends is common Such analysis is provided by both non profit groups as well as by for profit private institutions citation needed Forecasting foreign exchange movements is typically achieved through a combination of chart and fundamental analysis An essential difference between chart analysis and fundamental economic analysis is that chartists study only the price action of a market whereas fundamentalists attempt to look to the reasons behind the action 3 Financial institutions assimilate the evidence provided by their fundamental and chartist researchers into one note to provide a final projection on the currency in question 4 Forecasting has also been used to predict the development of conflict situations 5 Forecasters perform research that uses empirical results to gauge the effectiveness of certain forecasting models 6 However research has shown that there is little difference between the accuracy of the forecasts of experts knowledgeable in the conflict situation and those by individuals who knew much less 7 Similarly experts in some studies argue that role thinking standing in other people s shoes to forecast their decisions does not contribute to the accuracy of the forecast 8 An important albeit often ignored aspect of forecasting is the relationship it holds with planning Forecasting can be described as predicting what the future will look like whereas planning predicts what the future should look like 6 There is no single right forecasting method to use Selection of a method should be based on your objectives and your conditions data etc 9 A good place to find a method is by visiting a selection tree An example of a selection tree can be found here 10 Forecasting has application in many situations Supply chain management and customer demand planning Forecasting can be used in supply chain management to ensure that the right product is at the right place at the right time Accurate forecasting will help retailers reduce excess inventory and thus increase profit margin Accurate forecasting will also help them meet consumer demand The discipline of demand planning also sometimes referred to as supply chain forecasting embraces both statistical forecasting and a consensus process Studies have shown that extrapolations are the least accurate while company earnings forecasts are the most reliable clarification needed 11 Economic forecasting Earthquake prediction Egain forecasting Energy forecasting for renewable power integration Finance against risk of default via credit ratings and credit scores Land use forecasting Player and team performance in sports Political forecasting Product forecasting Sales forecasting Technology forecasting Telecommunications forecasting Transport planning and forecasting Weather forecasting flood forecasting and meteorologyForecasting as training betting and futarchy editIn several cases the forecast is either more or less than a prediction of the future In Philip E Tetlock s Superforecasting The Art and Science of Prediction he discusses forecasting as a method of improving the ability to make decisions A person can become better calibrated citation needed i e having things they give 10 credence to happening 10 of the time Or they can forecast things more confidently citation needed coming to the same conclusion but earlier Some have claimed that forecasting is a transferable skill with benefits to other areas of discussion and decision making citation needed Betting on sports or politics is another form of forecasting Rather than being used as advice bettors are paid based on if they predicted correctly While decisions might be made based on these bets forecasts the main motivation is generally financial Finally futarchy is a form of government where forecasts of the impact of government action are used to decide which actions are taken Rather than advice in futarchy s strongest form the action with the best forecasted result is automatically taken citation needed Forecast improvements editForecast improvement projects have been operated in a number of sectors the National Hurricane Center s Hurricane Forecast Improvement Project HFIP and the Wind Forecast Improvement Project sponsored by the US Department of Energy are examples 12 In relation to supply chain management the Du Pont model has been used to show that an increase in forecast accuracy can generate increases in sales and reductions in inventory operating expenses and commitment of working capital 13 Categories of forecasting methods editQualitative vs quantitative methods edit Qualitative forecasting techniques are subjective based on the opinion and judgment of consumers and experts they are appropriate when past data are not available They are usually applied to intermediate or long range decisions Examples of qualitative forecasting methods are citation needed informed opinion and judgment the Delphi method market research and historical life cycle analogy Quantitative forecasting models are used to forecast future data as a function of past data They are appropriate to use when past numerical data is available and when it is reasonable to assume that some of the patterns in the data are expected to continue into the future These methods are usually applied to short or intermediate range decisions Examples of quantitative forecasting methods are citation needed last period demand simple and weighted N Period moving averages simple exponential smoothing Poisson process model based forecasting 14 and multiplicative seasonal indexes Previous research shows that different methods may lead to different level of forecasting accuracy For example GMDH neural network was found to have better forecasting performance than the classical forecasting algorithms such as Single Exponential Smooth Double Exponential Smooth ARIMA and back propagation neural network 15 Average approach edit In this approach the predictions of all future values are equal to the mean of the past data This approach can be used with any sort of data where past data is available In time series notation y T h T y y 1 y T T displaystyle hat y T h T bar y y 1 y T T nbsp 16 where y 1 y T displaystyle y 1 y T nbsp is the past data Although the time series notation has been used here the average approach can also be used for cross sectional data when we are predicting unobserved values values that are not included in the data set Then the prediction for unobserved values is the average of the observed values Naive approach edit Naive forecasts are the most cost effective forecasting model and provide a benchmark against which more sophisticated models can be compared This forecasting method is only suitable for time series data 16 Using the naive approach forecasts are produced that are equal to the last observed value This method works quite well for economic and financial time series which often have patterns that are difficult to reliably and accurately predict 16 If the time series is believed to have seasonality the seasonal naive approach may be more appropriate where the forecasts are equal to the value from last season In time series notation y T h T y T displaystyle hat y T h T y T nbsp Drift method edit A variation on the naive method is to allow the forecasts to increase or decrease over time where the amount of change over time called the drift is set to be the average change seen in the historical data So the forecast for time T h displaystyle T h nbsp is given by y T h T y T h T 1 t 2 T y t y t 1 y T h y T y 1 T 1 displaystyle hat y T h T y T frac h T 1 sum t 2 T y t y t 1 y T h left frac y T y 1 T 1 right nbsp 16 This is equivalent to drawing a line between the first and last observation and extrapolating it into the future Seasonal naive approach edit The seasonal naive method accounts for seasonality by setting each prediction to be equal to the last observed value of the same season For example the prediction value for all subsequent months of April will be equal to the previous value observed for April The forecast for time T h displaystyle T h nbsp is 16 y T h T y T h m k 1 displaystyle hat y T h T y T h m k 1 nbsp where m displaystyle m nbsp seasonal period and k displaystyle k nbsp is the smallest integer greater than h 1 m displaystyle h 1 m nbsp The seasonal naive method is particularly useful for data that has a very high level of seasonality Deterministic approach edit A deterministic approach is when there is no stochastic variable involved and the forecasts depend on the selected functions and parameters 17 18 For example given the function f n x t 1 1 x t n n N x R displaystyle begin aligned f n x t dfrac 1 1 x t n qquad n in mathbb N x in mathbb R end aligned nbsp The short term behaviour x t displaystyle x t nbsp and the is the medium long term trend y t displaystyle y t nbsp are x t 1 a f n x t g y t d y t 1 b y t m x t h displaystyle begin aligned left begin array ll x t 1 alpha f n x t gamma y t delta y t 1 beta y t mu x t eta end array right end aligned nbsp where a g b m h displaystyle alpha gamma beta mu eta nbsp are some parameters This approach has been proposed to simulate bursts of seemingly stochastic activity interrupted by quieter periods The assumption is that the presence of a strong deterministic ingredient is hidden by noise The deterministic approach is noteworthy as it can reveal the underlying dynamical systems structure which can be exploited for steering the dynamics into a desired regime 17 Time series methods edit Time series methods use historical data as the basis of estimating future outcomes They are based on the assumption that past demand history is a good indicator of future demand Moving average Weighted moving average Exponential smoothing Autoregressive moving average ARMA forecasts depend on past values of the variable being forecast and on past prediction errors Autoregressive integrated moving average ARIMA ARMA on the period to period change in the forecast variable e g Box Jenkins Seasonal ARIMA or SARIMA or ARIMARCH Extrapolation Linear prediction Trend estimation predicting the variable as a linear or polynomial function of time Growth curve statistics Recurrent neural networkRelational methods edit Some forecasting methods try to identify the underlying factors that might influence the variable that is being forecast For example including information about climate patterns might improve the ability of a model to predict umbrella sales Forecasting models often take account of regular seasonal variations In addition to climate such variations can also be due to holidays and customs for example one might predict that sales of college football apparel will be higher during the football season than during the off season 19 Several informal methods used in causal forecasting do not rely solely on the output of mathematical algorithms but instead use the judgment of the forecaster Some forecasts take account of past relationships between variables if one variable has for example been approximately linearly related to another for a long period of time it may be appropriate to extrapolate such a relationship into the future without necessarily understanding the reasons for the relationship Causal methods include Regression analysis includes a large group of methods for predicting future values of a variable using information about other variables These methods include both parametric linear or non linear and non parametric techniques Autoregressive moving average with exogenous inputs ARMAX 20 Quantitative forecasting models are often judged against each other by comparing their in sample or out of sample mean square error although some researchers have advised against this 21 Different forecasting approaches have different levels of accuracy For example it was found in one context that GMDH has higher forecasting accuracy than traditional ARIMA 22 Judgmental methods edit Judgmental forecasting methods incorporate intuitive judgement opinions and subjective probability estimates Judgmental forecasting is used in cases where there is a lack of historical data or during completely new and unique market conditions 23 Judgmental methods include Composite forecasts citation needed Cooke s method citation needed Delphi method Forecast by analogy Scenario building Statistical surveys Technology forecastingArtificial intelligence methods edit Artificial neural networks Group method of data handling Support vector machinesOften these are done today by specialized programs loosely labeled Data mining Machine learning Pattern recognitionGeometric extrapolation with error prediction edit Can be created with 3 points of a sequence and the moment or index This type of extrapolation has 100 accuracy in predictions in a big percentage of known series database OEIS 24 Other methods edit Granger causality Simulation Prediction market Probabilistic forecasting and Ensemble forecastingForecasting accuracy editThe forecast error also known as a residual is the difference between the actual value and the forecast value for the corresponding period E t Y t F t displaystyle E t Y t F t nbsp where E is the forecast error at period t Y is the actual value at period t and F is the forecast for period t A good forecasting method will yield residuals that are uncorrelated If there are correlations between residual values then there is information left in the residuals which should be used in computing forecasts This can be accomplished by computing the expected value of a residual as a function of the known past residuals and adjusting the forecast by the amount by which this expected value differs from zero A good forecasting method will also have zero mean If the residuals have a mean other than zero then the forecasts are biased and can be improved by adjusting the forecasting technique by an additive constant that equals the mean of the unadjusted residuals Measures of aggregate error Scaled dependent errors edit The forecast error E is on the same scale as the data as such these accuracy measures are scale dependent and cannot be used to make comparisons between series on different scales Mean absolute error MAE or mean absolute deviation MAD M A E M A D t 1 N E t N displaystyle MAE MAD frac sum t 1 N E t N nbsp Mean squared error MSE or mean squared prediction error MSPE M S E M S P E t 1 N E t 2 N displaystyle MSE MSPE frac sum t 1 N E t 2 N nbsp Root mean squared error RMSE R M S E t 1 N E t 2 N displaystyle RMSE sqrt frac sum t 1 N E t 2 N nbsp Average of Errors E E i 1 N E i N displaystyle bar E frac sum i 1 N E i N nbsp Percentage errors edit These are more frequently used to compare forecast performance between different data sets because they are scale independent However they have the disadvantage of being extremely large or undefined if Y is close to or equal to zero Mean absolute percentage error MAPE M A P E 100 t 1 N E t Y t N displaystyle MAPE 100 frac sum t 1 N frac E t Y t N nbsp Mean absolute percentage deviation MAPD M A P D t 1 N E t t 1 N Y t displaystyle MAPD frac sum t 1 N E t sum t 1 N Y t nbsp Scaled errors edit Hyndman and Koehler 2006 proposed using scaled errors as an alternative to percentage errors Mean absolute scaled error MASE M A S E t 1 N E t 1 N m t m 1 N Y t Y t m N displaystyle MASE frac sum t 1 N frac E t frac 1 N m sum t m 1 N Y t Y t m N nbsp where m seasonal period or 1 if non seasonal Other measures edit Forecast skill SS S S 1 M S E f o r e c a s t M S E r e f displaystyle SS 1 frac MSE forecast MSE ref nbsp Business forecasters and practitioners sometimes use different terminology They refer to the PMAD as the MAPE although they compute this as a volume weighted MAPE For more information see Calculating demand forecast accuracy When comparing the accuracy of different forecasting methods on a specific data set the measures of aggregate error are compared with each other and the method that yields the lowest error is preferred Training and test sets edit When evaluating the quality of forecasts it is invalid to look at how well a model fits the historical data the accuracy of forecasts can only be determined by considering how well a model performs on new data that were not used when fitting the model When choosing models it is common to use a portion of the available data for fitting and use the rest of the data for testing the model as was done in the above examples 25 Cross validation edit Cross validation is a more sophisticated version of training a test set For cross sectional data one approach to cross validation works as follows Select observation i for the test set and use the remaining observations in the training set Compute the error on the test observation Repeat the above step for i 1 2 N where N is the total number of observations Compute the forecast accuracy measures based on the errors obtained This makes efficient use of the available data as only one observation is omitted at each stepFor time series data the training set can only include observations prior to the test set Therefore no future observations can be used in constructing the forecast Suppose k observations are needed to produce a reliable forecast then the process works as follows Starting with i 1 select the observation k i for the test set and use the observations at times 1 2 k i 1 to estimate the forecasting model Compute the error on the forecast for k i Repeat the above step for i 2 T k where T is the total number of observations Compute the forecast accuracy over all errors This procedure is sometimes known as a rolling forecasting origin because the origin k i 1 at which the forecast is based rolls forward in time 25 Further two step ahead or in general p step ahead forecasts can be computed by first forecasting the value immediately after the training set then using this value with the training set values to forecast two periods ahead etc See also Calculating demand forecast accuracy Consensus forecasts Forecast error Predictability Prediction intervals similar to confidence intervals Reference class forecastingSeasonality and cyclic behaviour editSeasonality edit Main article Seasonality Seasonality is a characteristic of a time series in which the data experiences regular and predictable changes which recur every calendar year Any predictable change or pattern in a time series that recurs or repeats over a one year period can be said to be seasonal It is common in many situations such as grocery store 26 or even in a Medical Examiner s office 27 that the demand depends on the day of the week In such situations the forecasting procedure calculates the seasonal index of the season seven seasons one for each day which is the ratio of the average demand of that season which is calculated by Moving Average or Exponential Smoothing using historical data corresponding only to that season to the average demand across all seasons An index higher than 1 indicates that demand is higher than average an index less than 1 indicates that the demand is less than the average Cyclic behaviour edit The cyclic behaviour of data takes place when there are regular fluctuations in the data which usually last for an interval of at least two years and when the length of the current cycle cannot be predetermined Cyclic behavior is not to be confused with seasonal behavior Seasonal fluctuations follow a consistent pattern each year so the period is always known As an example during the Christmas period inventories of stores tend to increase in order to prepare for Christmas shoppers As an example of cyclic behaviour the population of a particular natural ecosystem will exhibit cyclic behaviour when the population decreases as its natural food source decreases and once the population is low the food source will recover and the population will start to increase again Cyclic data cannot be accounted for using ordinary seasonal adjustment since it is not of fixed period Limitations editLimitations pose barriers beyond which forecasting methods cannot reliably predict There are many events and values that cannot be forecast reliably Events such as the roll of a die or the results of the lottery cannot be forecast because they are random events and there is no significant relationship in the data When the factors that lead to what is being forecast are not known or well understood such as in stock and foreign exchange markets forecasts are often inaccurate or wrong as there is not enough data about everything that affects these markets for the forecasts to be reliable in addition the outcomes of the forecasts of these markets change the behavior of those involved in the market further reducing forecast accuracy 2 The concept of self destructing predictions concerns the way in which some predictions can undermine themselves by influencing social behavior 28 This is because predictors are part of the social context about which they are trying to make a prediction and may influence that context in the process 28 For example a forecast that a large percentage of a population will become HIV infected based on existing trends may cause more people to avoid risky behavior and thus reduce the HIV infection rate invalidating the forecast which might have remained correct if it had not been publicly known Or a prediction that cybersecurity will become a major issue may cause organizations to implement more security cybersecurity measures thus limiting the issue Performance limits of fluid dynamics equations edit As proposed by Edward Lorenz in 1963 long range weather forecasts those made at a range of two weeks or more are impossible to definitively predict the state of the atmosphere owing to the chaotic nature of the fluid dynamics equations involved Extremely small errors in the initial input such as temperatures and winds within numerical models double every five days 29 See also editAccelerating change Cash flow forecasting Cliodynamics Collaborative planning forecasting and replenishment Computer supported brainstorming Earthquake prediction Economic forecasting Energy forecasting Forecasting bias Foresight future studies Frequency spectrum Futures studies Futurology Kondratiev wave Least squares Least squares spectral analysis Optimism bias Planning Prediction Predictive analytics Risk management Scenario planning Spending wave Strategic foresight Technology forecasting Thucydides Trap Time series Weather forecasting Wind power forecastingReferences edit French Jordan 2017 The time traveller s CAPM Investment Analysts Journal 46 2 81 96 doi 10 1080 10293523 2016 1255469 S2CID 157962452 a b Forecasting Principles and Practice Helen Allen Mark P Taylor 1990 Charts Noise and Fundamentals in the London Foreign Exchange Market The Economic Journal 100 400 49 59 doi 10 2307 2234183 JSTOR 2234183 Pound Sterling Live Euro Forecast from Institutional Researchers A list of collated exchange rate forecasts encompassing technical and fundamental analysis in the foreign exchange market T Chadefaux 2014 Early warning signals for war in the news Journal of Peace Research 51 1 5 18 a b J Scott Armstrong Kesten C Green Andreas Graefe 2010 Answers to Frequently Asked Questions PDF Archived from the original PDF on 2012 07 11 Retrieved 2012 01 23 Kesten C Greene J Scott Armstrong 2007 The Ombudsman Value of Expertise for Forecasting Decisions in Conflicts PDF Interfaces 1 12 Archived from the original PDF on 2010 06 20 Retrieved 2011 12 29 Kesten C Green J Scott Armstrong 1975 Role thinking Standing in other people s shoes to forecast decisions in conflicts International Journal of Forecasting 39 111 116 SSRN 1596623 FAQ Forecastingprinciples com 1998 02 14 Retrieved 2012 08 28 Selection Tree Forecastingprinciples com 1998 02 14 Retrieved 2012 08 28 J Scott Armstrong 1983 Relative Accuracy of Judgmental and Extrapolative Methods in Forecasting Annual Earnings PDF Journal of Forecasting 2 4 437 447 doi 10 1002 for 3980020411 S2CID 16462529 Department of Energy The Wind Forecast Improvement Project WFIP A Public Private Partnership Addressing Wind Energy Forecast Needs published 30 October 2015 accessed 9 December 2022 Logility Inc 2016 Beyond Basic Forecasting accessed 9 December 2022 Mahmud Tahmida Hasan Mahmudul Chakraborty Anirban Roy Chowdhury Amit 19 August 2016 A poisson process model for activity forecasting 2016 IEEE International Conference on Image Processing ICIP IEEE doi 10 1109 ICIP 2016 7532978 Li Rita Yi Man Fong Simon Chong Kyle Weng Sang 2017 Forecasting the REITs and stock indices Group Method of Data Handling Neural Network approach Pacific Rim Property Research Journal 23 2 123 160 doi 10 1080 14445921 2016 1225149 S2CID 157150897 a b c d e 2 3 Some simple forecasting methods OTexts Retrieved 16 March 2018 a href Template Cite book html title Template Cite book cite book a website ignored help a b Stoop Ruedi Orlando Giuseppe Bufalo Michele Della Rossa Fabio 2022 11 18 Exploiting deterministic features in apparently stochastic data Scientific Reports 12 1 19843 doi 10 1038 s41598 022 23212 x hdl 11311 1233353 ISSN 2045 2322 Orlando Giuseppe Bufalo Michele Stoop Ruedi 2022 02 01 Financial markets deterministic aspects modeled by a low dimensional equation Scientific Reports 12 1 1693 doi 10 1038 s41598 022 05765 z hdl 20 500 11850 531723 ISSN 2045 2322 Steven Nahmias Tava Lennon Olsen 15 January 2015 Production and Operations Analysis Seventh Edition Waveland Press ISBN 978 1 4786 2824 8 Ellis Kimberly 2008 Production Planning and Inventory Control Virginia Tech McGraw Hill ISBN 978 0 390 87106 0 J Scott Armstrong and Fred Collopy 1992 Error Measures For Generalizing About Forecasting Methods Empirical Comparisons PDF International Journal of Forecasting 8 69 80 CiteSeerX 10 1 1 423 508 doi 10 1016 0169 2070 92 90008 w Archived from the original PDF on 2012 02 06 16 Li Rita Yi Man Fong S Chong W S 2017 Forecasting the REITs and stock indices Group Method of Data Handling Neural Network approach Pacific Rim Property Research Journal 23 2 1 38 3 1 Introduction OTexts Retrieved 16 March 2018 a href Template Cite book html title Template Cite book cite book a website ignored help V Nos 2021 06 02 Probnet Geometric Extrapolation of Integer Sequences with error prediction Hackage Haskell org Archived from the original on 2022 08 14 Retrieved 2022 12 06 a b 2 5 Evaluating forecast accuracy OTexts Retrieved 2016 05 14 a href Template Cite book html title Template Cite book cite book a website ignored help Erhun F Tayur S 2003 Enterprise Wide Optimization of Total Landed Cost at a Grocery Retailer Operations Research 51 3 343 doi 10 1287 opre 51 3 343 14953 Omalu B I Shakir A M Lindner J L Tayur S R 2007 Forecasting as an Operations Management Tool in a Medical Examiner s Office Journal of Health Management 9 75 84 doi 10 1177 097206340700900105 S2CID 73325253 a b Overland Indra 2019 03 01 The geopolitics of renewable energy Debunking four emerging myths Energy Research amp Social Science 49 36 40 doi 10 1016 j erss 2018 10 018 ISSN 2214 6296 Cox John D 2002 Storm Watchers John Wiley amp Sons Inc pp 222 224 ISBN 978 0 471 38108 2 Sources editArmstrong J Scott ed 2001 Principles of Forecasting A Handbook for Researchers and Practitioners Norwell Massachusetts Kluwer Academic Publishers ISBN 978 0 7923 7930 0 Ellis Kimberly 2010 Production Planning and Inventory Control McGraw Hill ISBN 978 0 412 03471 8 Geisser Seymour June 1993 Predictive Inference An Introduction Chapman amp Hall CRC Press ISBN 978 0 390 87106 0 Gilchrist Warren 1976 Statistical Forecasting London John Wiley amp Sons ISBN 978 0 471 99403 9 Hyndman Rob J Koehler Anne B October December 2006 Another look at measures of forecast accuracy PDF International Journal of Forecasting 22 4 679 688 CiteSeerX 10 1 1 154 9771 doi 10 1016 j ijforecast 2006 03 001 Makridakis Spyros Wheelwrigt Steven Hyndman Rob J 1998 Forecasting Methods and Applications John Wiley amp Sons ISBN 978 0 471 53233 0 Malakooti Behnam February 2014 Operations and Production Systems with Multiple Objectives John Wiley amp Sons ISBN 978 0 470 03732 4 Kaligasidis Angela Sasic Taesler Roger Andersson Cari Nord Margitta August 2006 Upgraded weather forecast control of building heating systems In Fazio Paul ed Research in Building Physics and Building Engineering Taylor amp Francis CRC Press pp 951 958 ISBN 978 0 415 41675 7 Kress George J Snyder John May 1994 Forecasting and Market Analysis Techniques A Practical Approach Quorum Books ISBN 978 0 89930 835 7 Rescher Nicholas 1998 Predicting the Future An Introduction to the Theory of Forecasting State University of New York Press ISBN 978 0 7914 3553 3 Taesler Roger 1991 Climate and Building Energy Management Energy and Buildings 15 1 2 599 608 doi 10 1016 0378 7788 91 90028 2 Turchin Peter 2007 Scientific Prediction in Historical Sociology Ibn Khaldun meets Al Saud History amp Mathematics Historical Dynamics and Development of Complex Societies Moscow KomKniga pp 9 38 ISBN 978 5 484 01002 8 US patent 6098893 Berglund Ulf Stefan amp Lundberg Bjorn Henry Comfort control system incorporating weather forecast data and a method for operating such a system issued August 8 2000 External links edit nbsp Look up predict in Wiktionary the free dictionary nbsp Look up forecast in Wiktionary the free dictionary nbsp Media related to Prediction at Wikimedia Commons Forecasting Principles Evidence based forecasting International Institute of Forecasters Introduction to Time series Analysis Engineering Statistics Handbook A practical guide to Time series analysis and forecasting Time Series Analysis Global Forecasting with IFs Earthquake Electromagnetic Precursor Research Forecasting Science and Theory of Forecasting Retrieved from https en wikipedia org w index php title Forecasting amp oldid 1194274453, wikipedia, wiki, book, books, library,

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