Do Peep Shows "Cause" Crime? A Response to Linz, Paul, and Yao
McCleary, Richard, Meeker, James W., The Journal of Sex Research
Government regulation of adult entertainment businesses, including peep shows, must be aimed at mitigating adverse secondary effects such as crime. To determine whether San Diego's regulations meet this Constitutional threshold, Linz, Paul, and Yao (2006) compared police calls-for-service (CFSs) in peep show and control areas. Finding no significant difference, they concluded that San Diego has no legitimate rationale for regulating any aspect of peep shows. We disagree not only with the Linz et al. finding, but also with the logical adequacy of their conclusion. Their finding is a methodological artifact, in our opinion, and their conclusion is a fallacy. Before explaining our opinion, however, we disclose two facts.
First, although Linz et al. acknowledged that their article was based on an earlier paper, they did not acknowledge a still earlier report (Linz & Paul, 2002) commissioned by the plaintiffs in a lawsuit (Mercury Books v. City of San Diego, U.S. District Court, Southern District of California, 00-CV2461). This omission does not necessarily invalidate the Linz et al. finding, but the article's ancestry may be a material fact in judging its "suitability, credibility, and validity for publication" in a peer-reviewed journal (Horton, 2004, p. 821).
Second, we were retained by the defendant in that lawsuit, the City of San Diego, to write a rebuttal report (McCleary & Meeker, 2003). We have no connection to the Community Defense Counsel of Scottsdale, Arizona, however, or to any "politically conservative religious-based organization devoted to the strict regulation or elimination of sex businesses" (Linz et al., 2006).
With these facts disclosed, the Linz et al. finding is a methodological artifact of their novel design. This empirical error is compounded by a common hypothesis testing fallacy. Although Cook and Campbell (1979, p. 30) discussed both errors as threats to statistical conclusion validity, neither is well understood, at least in reference to criminological research.
THE NULL HYPOTHESIS AND TYPE II ERRORS
Linz et al. (2006) found that peep show areas had 210.4 (or 15.7%) more CFSs than other areas. Whereas any urban police department would judge a 15.7% difference in CFSs to be substantively significant, Linz et al. argued that the difference was not statistically significant and, thus, that there was no "reliable evidence of differences in crime levels between the control and test areas" (Linz et al.). This argument reflects a misunderstanding of the logic of hypothesis testing.
Figure 1 diagrams a test of the null hypothesis, [H.sub.0]. A Yes answer to "Do peep show areas have more CFSs?" rejects [H.sub.0] but runs the risk of a Type I (or [alpha]-type) error. By a convention dating to Fisher (1925), [H.sub.0] is rejected only if the probability of a Type I error is [alpha] < 0.05. Since [alpha] = 0.533 in this instance, Linz et al. decided not to reject [H.sub.0]. Had Linz et al. stopped here, their conclusion might be defensible. But Linz et al. argued further that not rejecting [H.sub.0] implies that [H.sub.0] is true--that "crime levels" around peep shows are no higher than the levels in other areas.
[FIGURE 1 OMITTED]
The risk of a Type II (or [beta]-type) error invalidates this argument. By a convention dating to Neyman and Pearson (1928), [H.sub.0] is accepted only if the probability of a Type II error is [beta] < 0.2. Figure 2 plots the Type II error function for the parameters reported (i.e., [n.sub.1] = [n.sub.2] = 19 areas, [alpha] = .05, and s = 304.5 CFSs. The function was calculated with PASS 6.0 [Hintze, 2001].). Since the probability of a Type II error for the 15.7% difference is [beta] = .508, there is no empirical basis for believing that [H.sub.0] is true. In this instance, [H.sub.0] is neither rejectable (because [alpha] [greater than or equal to] 0.05) nor acceptable (because [beta] …
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Publication information: Article title: Do Peep Shows "Cause" Crime? A Response to Linz, Paul, and Yao. Contributors: McCleary, Richard - Author, Meeker, James W. - Author. Journal title: The Journal of Sex Research. Volume: 43. Issue: 2 Publication date: May 2006. Page number: 194+. © 2007 Taylor & Francis Group, LLC. COPYRIGHT 2006 Gale Group.
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