We have prepared an SPSS syntax file that contains the formulas for computing IWI, plus instructions on how to prepare the indicators. With this file, IWI can without much difficulty be added to existing and new datasets.
To make things even easier, we have for a number of well-known data sources developed data files with the value of IWI for all included households. These IWI files are available for Demographic and Health Surveys, UNICEF MICS surveys, Latin America Barometers, Afro Barometers and some stand-alone surveys.
Most of these files can be freely downloaded. To obtain these files, please log in to My GDL and view the downloads page there. If you do not have a GDL account yet, you can register one for free.