Again, today I heard about the same thing. That is, in any lab experiment, if some subjects (ex: medical patients) have 2 observations, some have 3 observations, some have 4 observations.... apparently anova/hypothesis tests dont work .... but longitudinal regression apparently can still work.
Why? Can someone explain? Why can longitudinal model work for uneven measurements for patients.... but other analysis does not? Is there some statistical assumptions here that affect this?