Abstract: DIF is likely to occur in international surveys. What is needed is a statistical approach that takes DIF into account, while at the same time allowing for meaningful comparisons between countries. Zwitser,
Glaser, and Maris (2016) discuss some existing approaches and provide an alternative based on market
basket scoring (Mislevy, 1998). The core of this approach is to define the construct as a large set of items,
and to report in terms of summary statistics. Since the data are incomplete, measurement models are
used to complete the incomplete data. For that purpose, different models can be used across countries.
This talk will further discuss this approach. As part of that, the distinction between modeling DIF with,
for instance, country-specific parameters, and correcting for DIF in the scoring rule will be emphasized.
The method will be illustrated with PISA�s reading literacy data.

Keywords: basket scoring, DIF, modeling DIF