Category selection

This option is used when you have categorical variables in your data set. Select the DEA model to be used for assessing subsets of units by category and click ‘Category’. The pop up menu shown below will appear.

To add a new selection of DMUs which meet certain criteria on the categorical variables click the

icon. This will bring up a page similar to that illustrated below where the three categorical variables are ‘Location’, ‘size’ and ‘Int’ (international).

Using this screen you can choose a subset of DMUs by location, size and ‘Int’. For example if you were to highlight Loc1, Loc 2, Size 2 and both Y and N under ‘Int’ and then click on the selection automatically created the following page will be shown.

The screen above specifies the criteria the selected DMUs meet on the categorical variables. One could equally define another selection, ‘selection 2’ by say highlighting ‘Loc2’ and ‘1’ under location and size respectively. Then clicking the selection the screen will show that only DMUs in location 2 and of size 1 are selected.

If your selection is valid, 'Valid Syntax' in green as shown in the above illustration will be shown. It will also highlight if there is an error with the comment 'Invalid Syntax' allowing you to automatically change the syntax with the buttons above the window.

Once you are sure you have added the categories you wish to use correctly to a selection list you will need to press

in order to pull out the results of the categories chosen. A similar window to the one below corresponding to the categories selected will be shown.

Click on

to ensure your model changes are saved.