Original sentence: To determine whether their averaging of results was hiding a meaningful benefit to more-severely depressed patients by combining their results with those of moderately and mildly depressed patients, he and his colleagues undertook another study, this time of the four new-generation antidepressants for which all (published and unpublished) trial data were available, and concluded that the difference between drug and placebo effect was greater for more-severely depressed patients, and that this difference was clinically meaningful (but still relatively small) only at the upper end of the very severely depressed category
Edited sentence: To determine whether their averaging of results was hiding a meaningful benefit to more-severely depressed patients by combining their results with those of moderately and mildly depressed patients, he and his colleagues undertook another study, this time of the four new-generation antidepressants for which all (published and unpublished) trial data were available, and found that the difference between drug and placebo effect was greater for more-severely depressed patients, and that this difference was clinically meaningful (but still relatively small) only at the upper end of the very severely depressed category