Multi-item surveys are frequently used to study scores on latent factors. Such studies often include a comparison, between specific groups of individuals or residents of different countries, either at one or multiple points in time (i.e., a cross-sectional or a longitudinal comparison or both). If latent factor means are to be meaningfully compared, the measurement structures of the latent factor and their survey items should be stable, that is “invariant.”
Many studies examining MI of survey scales have shown that the MI assumption is very hard to meet. In particular, strict forms of MI rarely hold. Often, researchers just ignore MI issues and compare latent factor means across groups or measurement occasions even though the psychometric basis for such a practice does not hold. However, when a strict form of MI is not established and one must conclude that respondents attach different meanings to survey items, this makes it impossible to make valid comparisons between latent factor means.
In the current presentation I first discuss how to test for MI and what to do if this test fails using methods like partial MI, approximate MI and allignemnt. Also, we discuss what it means if you conclude groups can simply not be compared.
Every 2nd Thursday of the month, 11:30-12:30, Boothzaal, University Library Uithof.
Recording from earlier M&S powersnacks can be accessed on the Lecturenet website.