标题：Occurrences and sources of Differential Item Functioning (DIF) in patient-reported outcome measures: Description of DIF methods, and review of measures of depression, quality of life and general health
摘要：Examination of the equivalence of measures involves several levels, including
conceptual equivalence of meaning, as well as quantitative tests of differential
item functioning (DIF). The purpose of this review is to examine DIF in
patient-reported outcomes. Reviewed were measures of self-reported depression,
quality of life (QoL) and general health. Most measures of depression contained
large amounts of DIF, and the impact of DIF at the scale level was typically
sizeable. The studies of QoL and health measures identified a moderate amount of
DIF; however, many of these studies examined only one type of DIF (uniform).
Relative to DIF analyses of depression measures, less analysis of the impact of
DIF on QoL and health measures was performed, and the authors of these analyses
generally did not recommend remedial action, with one notable exception. While
these studies represent good beginning efforts to examine measurement
equivalence in patient-reported outcome measures, more cross-validation work is
required using other (often larger) samples of different ethnic and language
groups, as well as other methods that permit more extensive analyses of the type
of DIF, together with magnitude and impact.
关键词：Differential Item Functioning (DIF), measurement equivalence, patient-reported
outcomes, quality of life, depression, general health
