The Problem of Measurement Equivalence or Invariance in Instruments

The purpose of this study is to discuss the validity of equivalence in the sample groups of young and adult; females and males in the scale of assessing the attitudes towards foreign language skills and to offer the researchers that will use this scale certain evidence based on data. No measurement equivalence/invariance was found in adult and young groups. Consequently, measurement equivalence/invariance based on gender variable was not present, either. The absence of measurement equivalence/invariance is in fact a fundamental proof that the measurement instrument is specific to the group that it is intended for. For this reason, researchers should evaluate cross-validity or multi-group analyses on the basis of the traits that are measured using the measurement instrument. It is not always negative not to have measurement equivalence/invariance during the process of gathering validity evidences.