This example of a quasi-experiment in the news gives us a lot to think about. The headline reads, "New research shows one big change when cops wear cameras." The story introduced research on seven police precincts in the US and the UK. Here's how the journalist introduced the work:
Cameras worn on police uniforms have been lauded as a possible solution to many of the problems facing officers in the line of duty, from violence against law enforcement to the unnecessary use of force.
The report continues:
Researchers used complaints against police as a proxy for the effect of the cameras, hypothesizing that one major reason for complaints is that cops behaved in a negative, avoidable way. (There are other reasons for complaints, the researchers acknowledge, given the emotionally charged nature of many interactions with police.)
Compared to the previous year when cameras were not worn, complaints across the seven regions fell by 98% over the 12 months of the experiment. The study encompassed nearly 1.5 million officer hours across more than 4,000 shifts.
The news article contained a bar graph, depicting that in the year before the cameras were used, the total number of police complaints was almost 1600. In the year after the cameras were used, the total complaints was fewer than 200.
a) This research used a quasi experimental design. What is the IV? What is the DV? Is the IV an independent groups variable or a within-groups variable?
b) What kind of design is this--nonequivalent control group posttest only, nonequivalent control group pretest-posttest, interrupted time series, or nonequivalent control group interrupted time series?
c) The authors of the report seem convinced that body cameras are the reason for the drop in police complaints seen from one year to the next. But what other possible explanations could there be? What threats to internal validity might apply here, and which could you rule out? (Consult Table 11.1 or Chapter 13.)
d) In a quasi-experiment, we use both the design and the results to see how close we can get to supporting a causal statement. What changes to this study's design might help you be more convinced that the study can support the claim that "body cameras reduce police complaints"?
Thanks to Dr. Carrie Smith (Ole Miss) for this story idea!