lCohen (1977): .2
= small

.5 = moderate

.8 = large

lWolf (1986):
.25 = educationally

significant

significant

.50 = practically signficant

(therapeutic)

(therapeutic)

lESs are proportional, e.g.,

.40 is twice as much change as .20

.40 is twice as much change as .20

Interpreting Effect Size (*d*)