“…All but one of the 12 studies produced a positive average effect with the range of average effect sizes being from -0.05 to 0.99. A summary of the findings for this analysis and for a combination of this and the Baker and Popowicz (1983) analyses appears in Tables 1 and 2 Johnson, 1980Randolph & Grantham, 1973Regehr & Herman, 1981Swails & Herr, 1976Thoresen & Hamilton, 1972Weeks, Thornburg, & Little, 1977Wilson & Daniel, 1981Yongue, Todd, & Burton, 1981 Average effect size Overall Average effect size Johnson, Johnson, & Yates, 1981Meir & Shiran, 1979Motsch, 1980O'Bryant & Corder-Bolz, 1978Prediger & Noeth, 1979 not used by Baker and Popowicz, the effect sizes reported in the current tables will be slightly lower.…”