READ THE DAMN DOCUMENTATION (CAREFULLY). A case study using the PISA data.

When you get access to a new dataset, do you always carefully read the documentation first? We all know we should. But – let’s be honest – it’s a lot more fun to just start playing with the data. This can however be a dangerous game to play. This paper presents a case study of this matter using the OECD’s Programme for International Student Assessment (PISA). A survey question included in this study attempts to measure student truancy across countries over time. The international survey documentation suggests an identical question has been used across countries and cycles. Yet the national documentation illustrates how a subtle – yet important – change to the wording was made in some countries in 2015. We demonstrate how researchers could easily miss this change and how this would impact inferences in changes in truancy rates before and after the COVID-19 pandemic. Attempts to use artificial intelligence and large language models to spot this problem resulted in overconfidently incorrect advice. The findings thus serve as a reminder to even the most experienced data analysts (including ourselves) – ALWAYS READ THE SURVEY DOCUMENTATION CAREFULLY.