Source A: The mean outcome score improved after the intervention.
Source B: Variability was high, and some participants' scores got worse.
Source C: Benefit depended on participants' baseline severity.
Using the sources, to what extent can we conclude that the intervention improves outcomes for everyone?
Essay preview
We can conclude only to a limited extent that the intervention improves outcomes for everyone. The strongest support for the claim comes from Source A, which states that “the mean outcome score improved after the intervention”. This suggests that, overall, the intervention had a positive effect at the group level. If t