Forecasting
Forecasting is the process of making statements about events whose actual outcomes (typically) have not yet been observed. A commonplace example might be estimation of some variable of interest at some specified future date.
Predictions of outcomes based on data and prediction models. Forecasting involves Predictive Modelling.
There are millions of datasets out there. There are thousands of models. They determine the quality of forecasts. Reducing error is always an issue.
There are various forecasting methods listed below:
Contents
Extrapolative Methods
Extrapolative methods are to infer or estimate by extending or projecting known information.
#  Method  Description  Actuary Usage  Business Usage 

1  Moving Average, Simple Moving Average  Frequently used  Widely used  
2  Exponential Smoothing 

Generally not used  Widely used for TS analysis 
3  Auto Regression Moving Average (ARMA)  Generally not used  Widely used 
Explanatory Variable Methods
Use of a variable that explains a related response variable. Often called an independent variable or predictor variable.
#  Method  Description  Actuary Usage  Business Usage 

1  Regression Analysis 

Widely used  Widely used 
2  Predictive Modeling  Gaining popularity  Widely used  
3  Artificial Neural Networks  Generally not used  Sometimes used  
4  Econometric Modeling  Generally not used  Widely used 
Simulation Modeling Methods
#  Method  Description  Actuary Usage  Business Usage 

1  Cellbased Modeling  Frequently used  Frequently used  
2  Systems Dynamics Simulation  Generally not used  Becoming more widely used  
3  Multiagent Simulation  Generally not used  Becoming more widely used 
Judgmental Methods
 Composite forecasts
 Surveys
 Delphi Method
 Scenario building
 Technology forecasting
 Forecast by analogy
Composite Methods
#  Method  Description  Actuary Usage  Business Usage 

1  Bayesian Forecasting  Generally not used  Generally not used  
2  Others?  Generally not used  Generally not used 
Forecasting
People
 Rob Hyndman  http://robjhyndman.com/
Forecasting Models
Every industry has its "models". These range in the thousands.
 520day Moving Average  Trading
 RainfallRunoff Models  Hydrology
 Logistics optimisation models
 Finance optimisation models
 Economic Models
 Finance Models
Examples
 Trading Models
 http://www.forexnet.lv/EditModule.aspx?tabid=590&mid=1044&def=News%20Article%20View&ItemId=718
 http://blogs.wsj.com/numbersguy/gradingtheforecastsofexperts182/
 http://blog.centage.com/
 http://en.wikipedia.org/wiki/Forecasting#Categories_of_forecasting_methods
 http://en.wikipedia.org/wiki/Forecasting
 http://www.ipredict.it/ForecastingMethods.aspx