Reports using past PISA data have suggested that in many of the OECD countries, immigrant students are underperforming in comparison to their non-immigrant peers. With the rapidly increasing number of immigrant students throughout Europe, these disturbing fi ndings have drawn much attention to how well various immigrantreceiving countries are addressing the needs of their immigrant student population. But how accurate are these fi ndings? In this paper, we argue that, when analyzed at the aggregate, surface level, there are three possible pitfalls that may give researchers and policymakers an incomplete or biased picture of how immigrant students in various OECD countries are faring. These shortcomings stem from 1) how immigrant students are selected or categorized, 2) the test language profi ciency level of the fi rstgeneration students, and 3) the way in which the fi rst and second generation immigrant students are grouped. In this paper, these shortcomings are addressed and possible remedies are discussed.