Onderzoek Naar Oorzaken van 'Differential Item Functioning' in de Eindtoets Basisonderwijs

Previous research has shown that the Dutch 'Final Test of Primary Education' contains a number of unintentionally and therefore unwanted, difficult test items, leading to Differential Item Functioning (DIF) for immigrant minority students whose parents' dominant language is Turkish or Arab/Berber. Two statistical procedures were used to identify DIF-items in the Final Test of 1997. Subsequently, five experiments were conducted to detect causes of DIF, revealing a number of hypotheses concerning possible linguistic, cultural, and textual sources. These hypotheses were used to manipulate original DIF-items into intentionally DIF-free items. The article discusses three possible sources of DIF: (1) the use of fixed (misleading) answer-options and (2) of misleading illustrations (both in the disadvantage of the minority students), and (3) the fact that questions concerning past tense often lead to DIF (in their advantage).