In addition to reporting statistical significance, it is highly recommended that effect size or some measure of strength of effect be reported. The current Results section reports a basic form of effect size called Cohenís d. The general conventions for the labeling of effect sizes are as follows: .2 is small, .5 is medium, and .8 is large. Cohenís d is easily calculated by hand and the components of this calculation can be found on the SPSS Output Analysis. Essentially, Cohenís d is equal to the mean difference divided by the standard deviation. In the case of a between-subjects design, the analysis will report one standard deviation value for each of the two groups. Before dividing the mean difference by a standard deviation value, the weighted average for these two should be calculated and used as the denominator.