title: How to find nothing.
abstract: Hypothesis testing can be misused and misinterpreted in various ways. Limitations in the research design, for example, can make it almost impossible to reject the null hypothesis that a policy has no effect. This article discusses two examples of such experimental designs and analyses, in which, unfortunately, the researchers touted their null results as strong evidence of no effect.
authors.affiliation: Health Policy and Management, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: David
authors.initials: D
authors.lastname: Hemenway
mesh_terms: D002140:California; D003132:Commerce; D003627:Data Interpretation, Statistical; D005389:Firearms; D006708:Homicide / Q000639:trends; D006801:Humans; D009014:Morals; D009026:Mortality; D012107:Research Design; D013781:Texas