As evaluations of CCTV camera systems have increased and improved methodologically over the years (see Piza et al. 2019), one striking development has been a focus on the use of microunits of analysis (see Chapter 2, Topic 2.3 in the current volume). Crucial to the evaluation of CCTV is the use of control areas that are comparable to the treatment areas receiving the intervention. Systematic reviews of the effects of CCTV on crime have shown that the minimum acceptable evaluation design involves measures of crime before and after the program in treatment and comparable control areas (Piza et al. 2019). This design rules out many threats to internal validity, allowing for—in the absence of random allocation—a fair comparison of like with like.