In the 19 FH comparisons, FH+ status was associated with a lower overall subjective response to alcohol (i.e., across stimulation, sedation and other measures and across both limbs and the peak of the BAC curve), g = −0.24 (95% CI: −0.49, 0.00). That is, FH+ participants reported lower subjective response relative to FH− participants, although this effect was small in size. Beyond the mean point estimate of effect size, however, there was significant heterogeneity in effect sizes across studies, Qwithin(18) = 42.51, p = .001, I2 = 57.66. As indicated by the I2 statistic, between-study variability accounted for 58% of the variance in effect sizes. Rosenthal’s (1979) fail-safe N indicated that an additional 29 samples (i.e., more than 1.5 times the number of included samples) with null findings would be necessary to render the overall effect non-significantly different from zero.
