It is often believed that running a model historically, and comparing its results against actual historical data is a good test of model validity. Although this is not strictly true, it is useful. The menu option Open IFsBaseHist (sub-option Switch) opens up a run of the IFs model from 1960 through the base year of the model and allows this kind of analysis. It is a toggle switch and can also bring back the normal IFs forecast from the base year.
Click on Open IFsBaseHist to access the historic empirical data and the historical forecasts. It will take a moment to load all of the variables and parameters. This process of toggling to the historical base is complete when the Open IFsBaseHist prompt is replaced with the Open IFsBase prompt. You now have access to the historic run of the model for the purpose of validation and also have access to empirical historical data for comparison with the historical forecasts or for export.
When the Open IFsBaseHist/Open IFsBase is toggled to history, an additional option is loaded into the Self Managed (Full Variable/Parameter Selection) Display menu: History Variable Options. This feature allows users to organize and validate the model by comparing forecasted historic data against empirical historic data. Its sub-options are:
Select from Forecasted Historical Variables (the default)
This option allows users to display variables that are forecasted from 1960 to the base year of the model. This default option does not change the appearance of the entries in the Type Name Box; all parameters and variables are available to you, but from the historical run. When this is selected, two run-files appear in the Files Available for Display Box: 0 – Working File, based on IFsBaseHist.run and 1 – IFSBASEHIST.run.
Select from Empirical Historical Variables
This option changes the list of entries in the Type Name Box and the entries become all of the empirical series in the IFs historical database. This listing here now allows selection of historical series to compare with forecasted ones (you can add a forecasted one to the Status Box, switch to empirical historical variables and add a similar one from data, and then click on Go to Display to see the degree to which historical forecasts parallel data). You can also simply explore historical series over time for the geographic elements of interest to you, similar to what is possible in longitudinal analysis under the Data Analysis option of the Main Menu. When this option is selected, the run-file available in the Files Available for Display Box changes to -1 History Data from IFS_HistSeries.MDB.
Another useful feature of Open IFsBaseHist is the ability to export data from the IFs historic database. First of all, if you would like to choose empirical data from the IFs dataset, you must select History Variable Options and the Select from Empirical Historical Variables. This removes forecasted variable names from the Type Name Box and only displays historic, empirical data series names. Now, select a series name that you would like to export from IFs. After choosing this series, you will be prompted to choose a geographic unit. If you are selecting from countries/regions, it is possible to select all of these units simultaneously by selecting ALL, located at the bottom of the list of countries/regions that appear. Clicking on Go to Display will bring up the Display Form. From its menu, click on Table and then click on Save.
*Note: When IFsBaseHist is opened, it will remain opened until users choose to re-open IFsBase.