Evidence-based practice (EBP) comprises a number of “tools” in its toolbox. These include (1) being able to phrase a question in such a way that you can carry out a useful literature search; (2) knowing how to do the search; and (3) having an understanding of the basic terminology, such as absolute risk reduction (ARR) and number needed to treat (NNT). This paper introduces the concepts of ARR and NNT and explains why they are necessary to supplement the more widely used statistic, the relative benefit ratio. Using an example of a realistic clinical question, we show how to conduct a literature search to find the best available evidence and how to translate the findings into a meaningful decision about the effectiveness of a therapeutic intervention. Next, we show how a secondary analysis of an administrative database of 2,525 psychiatric inpatients can be used to identify self-harm risk factors in a group of suicidal substance-abusing patients. Finally, we examine significant findings among the 740 former patients who were readmitted within 31 days of discharge, owing to evidence of clear and present risk of harm to self or others.