Empirical Strategies for Research on Pornography Effects
Two of the biggest challenges to estimating the effect of pornography on various outcomes are: omitted variable bias and reverse causality. Omitted variable bias occurs when some other factor influences both pornography use and the outcome of interest. Reverse causality occurs when the outcome of interest (e.g. marital quality) is affecting the use of pornography.
One way to deal with both of these problems is to identify some source of variation in pornography use that is both exogenous (unaffected by the person's decisions) and does not have a direct effect on the outcome of interest except through the use of pornography.
Our goal here is to document potential sources of variation in either access or exposure to pornography that could provide a credible empirical strategy. In each case, we briefly describe the strategy, provide links to studies using each approach and links to related data. We welcome any studies, data or empirical strategies that we have left out (firstname.lastname@example.org).
Various technologies that have provided easier access to pornography have been diffused at different rates in different parts of the country. Thus, two otherwise similar individuals may have had access to a particular technology (and hence pornography) at different points in time. These technologies include: VCRs, cable, satellite television, internet connection, and high-speed internet.Studies: Kendall (2007)—internet Data: Current Population Survey—Computer Use supplement
Post Office Boxes
"An important cost most individuals must consider when deciding how much pornography to consume is the possible embarrassment that could arise if other people find out about such personal purchases. One way of reducing this risk is by receiving pornographic material through private, semi-anonymous post office boxes. Delivery through such channels guarantees confidentiality, since it eliminates the possibility of family, friends, or neighbors inadvertently discovering the material during the process of home delivery. The availability of post offices boxes, however, varies significantly from region to region. It seems plausible, therefore, to hypothesize that areas in which post office boxes are abundantly available will on average tend to have higher levels of pornography consumption." (Wongsurawat 2006)Studies: Wongsurawat (2006) Data: currently scanning 1990—2000 (available soon)
Anti–Obscenity Laws (Comstock laws)
The Comstock Act, enacted in 1873, is a federal law that prohibits selling, lending, or distributing "any obscene book, pamphlet, paper, writing, advertisement, circular, print, picture, drawing, or other representation, figure or image on paper or other material" (Ch. 257, 17, Stat. 598). One goal of the federal law was to encourage states to enact similar laws, which many did.Studies: Bailey (2008)—[legal appendix] Data: Future project.
School Level Internet Subsidies
"As part of the Telecommunications Act of 1996, the government began actively subsidizing Internet and telecommunications in U.S. classrooms... The new initiative, known as the E-rate program, began in 1998 and provides up to $2.25 billion per year of subsidies to schools and libraries" (Goolsbee and Guryan 2006). The subsidy depends on the number of students who receive free or reduced price lunch with a subsidy rate that varies from 20-90%.Studies : Goolsbee and Guryan (2006) Data:
- 7-11's change in policy
- Copyright laws
- Digital Rights Management
- Filtering technology
- Self regulation by search engines.