Demonstration That the Claim That Brighter Lighting Reduces Crime Is Unfounded

• NCJ Number: 206769
• Journal: British Journal of Criminology Volume: 44 Issue: 3 Dated: May 2004 Pages: 441-447
• Author(s): P. R. Marchant
• Date Published: May 2004
• Length: 7 pages
• Publication Format: Article
• Publication Type: Program/Project Evaluation
• Language: English
• Country: United Kingdom
• Note: For a response to this critique, see NCJ-206770.

Annotation

This paper critiques the methodology and findings of the British Home Office Research Study 251 (HORS 251), which is a major systematic review of studies that have examined the impact of street lighting on crime; HORS 251 concluded that claims for the effectiveness of lighting in reducing crime are justified.

Abstract

HORS 251 compared the ratio of number of crimes before and after brighter lighting was introduced in an area with the ratio of a similar ratio in a "control" area that had no change in lighting. HORS 251 calls this ratio of ratios an "odds ratio" (OR). If the OR is significantly greater than one then it might be concluded that crime has been reduced in the newly lit area compared with the control area. Data for the 13 studies included in the review produced OR's generally greater than 1, suggesting that crime declined in the newly lit areas compared with the control areas. This conclusion appears to be formally strengthened by the point labeled Mean, as this represents the weighted average of all 13 studies and shows an OR greater than 1 with a narrow confidence interval around it; however, the current critique shows that the true confidence interval should be much wider, such that it is not possible to determine whether lighting reduces or indeed increases crime. Different statistical methods are required to deal with such variability. Where it has been possible to reanalyze the data, the appropriate methods have not provided satisfactory evidence that brighter lighting reduces crime. There are also other problems with the review, including not comparing like with like for the individual studies. This is because brighter street lighting is applied to more crime-ridden areas, and the comparison areas are less crime-ridden, leading to an effect known as "regression to the mean." Other problems with HORS 251 are the unjustified exclusion from the review of small-size studies and the failure to identify the source of funding for each study (needed to determine whether bias might be injected into the study). Thus, there is currently no scientific basis for the argument that increased lighting reduces crime. 5 figures and 6 references