I have *three waves* of data for individual children:
(1) Time 0 = Kindergarten (readiness for school measure) (2) Time 1 = Grade 4 (academic achievement measure) (3) Time 2 = Grade 7 (academic achievement measure)
My ultimate interest is seeing the way in which children's developmental trajectories (from Time 0 to Time 1 to Time 2) vary across residential neighbourhoods.
Here is the rub: Because the Time 0 measure is 'non-equatable' with the Time 1&2 measures (they measure different constructs), then I *cannot* include the measures in a three-wave growth model, or else the results would simply be uninterpretable (as per Singer & Willett, 2003).
Therefore, can I instead run a regular two-level HLM model (kids within neighbouhoods) within the SEM framework, in which the Time 2 measure is my DV and the Time 0&1 measures simply serve as Level-1 predictors?
If so, can I use SEM to explore both (a) the effect of particular Level-1 mediators and (b) the role of particular Level-2 predictors?