Reading for January 8

1. In two papers have the author claimed that initial measurements and relative change/change scores are negatively correlated. My simple simulations indicate that this is not always the case.

2. Clarification needed when using change scores (paper 4): Does the author imply that the common way of defining Treatment_Effect =(average change score in Treatment group)- (average change score in Control group)? I do not understand his claim that this treatment effect is affected by regression toward the mean if baseline imbalance exists.

3. Regarding "Analysing controlled trials...": the author appeared a strong advocate for using ANCOVA. However, I feel he does not emphasize enough, for the intended audience, that several strong assumptions must be satisfied. It would be interesting to investigate the Type I error (Ho:no treatment effect) of ANCOVA vs using change scores when the ANCOVA assumption of homogeneity of regression slope is incorrect.