Treating Youth in Conflict with the Law: A New Meta-Analysis

Figure 3.1 Effect Size Distribution (Recidivism)

Figure 3.1 is a horizontal bar graph that illustrates the effect size distribution for 176 programs that directly measured the effectiveness of treatment on reducing future criminal behaviour. The x-axis represents the number of effect sizes, ranging from 0 to 45. The y-axis represents the value of the effect sizes (in intervals), ranging from -.50 to -.41 to .60 to .69. A horizontal line cuts across the centre of the graph to illustrate where the 0 value lies (all values below this line are negative effect sizes while all above the line are positive).

The results show that largest number of effect-sizes cluster in the middle of the graph, peaking at the 0.0 to .09 range (about 43) and then the distribution declines steadily towards the positive and negative ends of the graph. The resulting shape resembles a normal distribution (a bell shape), with the largest number of effect sizes occupying the centre of the graph, and then declining steadily until the distribution reaches each end of the graph, where the number of effect sizes are very low (about 4 at .60 to .69 on the positive end and about 3 at -.50 to -.41 on the negative end).

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