“…Studies used convenience samples of available examiners, and no study used power calculations to calculate the number of examiners actually needed to detect desired differences in effect size from the intervention. Trends toward overall improvement were found in some studies 30,35,36,38,41 ; however, notably, no effect was found even in the largest study, which used a multiple-intervention design over a longer period of time. 44 Second, short intervals (months for most studies) may detect changes that are not sustainable over time.…”