Review of previous RCTs assessing child cognitive development and music lessons.

Note. Studies are reviewed in chronological order, from 1999 [5] to 2011 [9]. Standard deviations, where available, are in parentheses. This table was completed with the generous assistance of the authors of each of the above papers, who helped clarify a variety of relevant statistics from their work.1As of November 2013, from Google Scholar.2Value represents an estimate; exact value was not available from the author(s).3The effect size reported in [7] is d = .35, a figure calculated in terms of the pooled standard deviation of children's increases in IQ score. However, the relevant effect size is in terms of the standard deviation of the test itself, not that of gain scores (see, e.g., [56]). Thus, we recalculated the effect size using the standard deviation of the WISC-III's reference population (fifteen IQ points [10]) and report this figure above.