Who Needs Linear Equating Under the NEAT Design?

摘要

If a measurement invariant latent variable model does not underlie the data, then the entire equating procedure comes down to skating on very thin ice; for it is, in that case, not clear what one is actually doing (certainly not equating the responses of the different groups). In this case, therefore, the linear equating methods proposed would seem to be useless. However, if a measurement invariant latent variable model does underlie the data, then (a) the assumptions of the linear methods are unlikely to be met and (b) there are easier and more appropriate ways of handling the situation, namely through an IRT analysis. The only use we can imagine for linear equating methods of the kind investigated by Kane et al. in the present papers is as first-order approximations to the proper analysis through IRT. To investigate the appropriateness of these approximations, however, one would need to do the IRT analysis anyway, and if one has done that analysis, the linear equating methods are no longer necessary.