Selection Bias in Web Surveys and the Use of Propensity Scores
The most obvious potential drawback of web surveys is that they may not be representative of the population of interest because the sub-population with access to Internet is quite specific. In Selection Bias in Web Surveys and the Use of Propensity Scores (SSRN) (RAND Working Paper No. WR-279) the authors investigate propensity scores as a method for dealing with selection bias in web surveys.
Findings. The propensity adjustment works well for many but not all variables investigated. For example, they find that correcting on the basis of socio-economic status by using education level and personal income is not enough to get a representative estimate of stock ownership. This casts some doubt on the common procedure to use a few basic variables to blindly correct for selectivity in convenience samples drawn over the Internet. Alternatives include providing non-Internet users with access to the Web or conducting web surveys in the context of mixed mode surveys.
See also: Are 'Webographic' or Attitudinal Questions Useful for Adjusting Estimates from Web Surveys Using Propensity Scoring? (SSRN)(RAND Working Paper Series No. WR-506). [JH]
Iran Blocks Access to Women's Issues and Human Rights Websites
Iran's Ministry of Islamic Guidance and Culture's supervisory board for the media has decided to block access to several websites related to women's issues and human rights. Iranian Internet service providers were notified last week about the new restrictions. The Washington Post is reporting that Iranian bloggers and activists on Tuesday condemned the move as unlawful censorship. [JH]
PBWiki Hits 500,000 Users
Mashable reports that PBWiki, which will celebrate its third anniversay on May 31st, has crossed a major milestone, 500,000 users. Check out the recent Mashable interview with Chris Yeh of PBWiki (mp3) which provides an interesting overview of the hosted wiki space in general as well as a brief history of PBWiki in specific. [JH]
Save the Date for Free May 21 Blogging Webinar
"The Power of Blogging" is a free webinar on May 21st at 1 pm EDT by TypePad and Bella Web Design for businesses that want to learn how blogging can set one's company apart by generating leads and communicating with present and future clients. The webinar hosts will be Desiree Scales, CEO of Bella Web Design, and Andy Wibbels, TypePad team member and author of the book Blogwild! A Guide for Small Business Blogging. Register here. [JH]
About 25% of Am Law 200 Firms Blog
LexBlog reports that as of mid-March, 53 Am Law 200 firms were blogging in some manner. Read more about BigLaw blogging at Cutting a Winning Edge in Law Firm Blogs (American Lawyer, May 2, 2008). Hat tip to Mitch Rubinstein, Adjunct Law Prof Blog. [JH]
Drew Indicted for Computer Fraud and Abuse Act Violation
Lori Drew was indicted on Thursday for her alleged role in a hoax on MySpace directed at Megan Meier, a 13-year-old neighbor of Drew's who committed suicide in October 2006 after a "boy" she met on MySpace abruptly turned on her and ended their relationship. Drew was charged with one count of conspiracy and three counts of accessing protected computers without authorization to get information used to inflict emotional distress on the girl. Each of the four counts carries a maximum possible penalty of five years in prison. Text of Indictment (pdf), Computer Fraud and Abuse Act