Logic and Reasoning in Crime Analysis

Logic and reasoning is a core skill of the applied crime analyst. Without an understanding of what constitutes good logic and critical thinking, the analyst will fail to provide sound advice or opinion, barring the most exceptional cases of luck. To do so, the analyst will use both inductive and deductive logic to develop theories and to test these theories against the evidence using the scientific method. Then, and only then, will the conclusions be sound and stand up to scrutiny. In an ideal world, one hypothesis will remain to the exclusion of all others, although this is often not possible within the boundaries of the evidence one has. In these cases, competing hypotheses can be measured against one another using Heuer's ACH methodology. This chapter discusses logic and reasoning, provides some understand of cognitive tools in the form of heuristics, and discusses some cognitive errors to be avoided.