One conclusion is that grouping programs usually have only small effects on student self - esteem. (davidsongifted.org)
While some studies indicate that breastfeeding has only a very small effect on childhood obesity, the effect seems to be fairly persistent. (ourfamilyworld.com)
The investigated gene variants are present in around 1/3 of the population, so they are common variants with small effect size. (sciencedaily.com)