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PDFincorrectly) yielding an underblocking rate in this
example of only .2%.
According to Biek, the sample size that he used yielded a
95% confidence interval of plus or minus 3.11%.
Edelman is a Harvard University student and a systems
administrator and multimedia specialist at the Berkman Center for Internet and Society at Harvard Law School. Despite Edelman’s young age, he has been doing consulting work on Internet-related issues for nine years, since he was in junior high school.
The archiving process in some cases took up to 48 hours
from when the page was blocked.
In October 2001, Edelman published the results of his
initial testing on his Web site. In February and March 2002 he repeated his testing of the 6,777 URLs originally found to be blocked by at least one of the blocking products, in order to determine whether and to what extent the blocking product vendors had corrected the mistakes that he publicized. Of those URLs blocked by N2H2 in the October 2001 testing, 55.10% remained blocked when tested by Edelman in March 2002. Of those URLs blocked by Websense in the October 2001 testing, 76.28% remained blocked when tested by Edelman in February 2002. Of those URLs blocked by SurfControl’s Cyber Patrol product, only 7.16% remained blocked, i.e., Cyber Patrol had unblocked almost 93% of the Web pages originally blocked. Because the results posted to his Web site were accessed by an employee of SurfControl (as evidenced by Edelman’s records of who was accessing his Web site), we infer that Cyber Patrol had determined that 93% of all 6,777 pages, or 6,302 Web pages, were originally wrongly blocked by the product.
Two other expert witnesses reviewed subsets of the list
of Web pages that Edelman compiled. Dr. Michael T. Ryan, Director of the Rare Book and Manuscript Library and of the Center for Electronic Text and Image at the University of Pennsylvania, reviewed a list of 204 sites that Edelman forwarded to him in order to determine their appropriateness and usefulness in the library setting. Because the sites that Ryan reviewed were not selected randomly (i.e., they were chosen by plaintiffs’ counsel), his study says little about the character of the set of 6,777 sites that Edelman compiled, or the total amount of overblocking by the four filtering programs that Edelman used. Anne Lipow, a practicing librarian for more than 30 years and the director of a library consulting firm, also reviewed the same list of 204 URLs from the set that Edelman had collected for their appropriateness for a library’s collection. She categorized sites in four different levels according to their appropriateness for a public library’s collection. Again, because these URLs were not selected randomly, Lipow’s study is not particularly relevant to the total set that Edelman compiled, or to the total amount of overblocking by the four filtering programs that Edelman used. Although the methodology used
According to Biek, the sample size that he used yielded a
95% confidence interval of plus or minus 3.11%.
Edelman is a Harvard University student and a systems
administrator and multimedia specialist at the Berkman Center for Internet and Society at Harvard Law School. Despite Edelman’s young age, he has been doing consulting work on Internet-related issues for nine years, since he was in junior high school.
The archiving process in some cases took up to 48 hours
from when the page was blocked.
In October 2001, Edelman published the results of his
initial testing on his Web site. In February and March 2002 he repeated his testing of the 6,777 URLs originally found to be blocked by at least one of the blocking products, in order to determine whether and to what extent the blocking product vendors had corrected the mistakes that he publicized. Of those URLs blocked by N2H2 in the October 2001 testing, 55.10% remained blocked when tested by Edelman in March 2002. Of those URLs blocked by Websense in the October 2001 testing, 76.28% remained blocked when tested by Edelman in February 2002. Of those URLs blocked by SurfControl’s Cyber Patrol product, only 7.16% remained blocked, i.e., Cyber Patrol had unblocked almost 93% of the Web pages originally blocked. Because the results posted to his Web site were accessed by an employee of SurfControl (as evidenced by Edelman’s records of who was accessing his Web site), we infer that Cyber Patrol had determined that 93% of all 6,777 pages, or 6,302 Web pages, were originally wrongly blocked by the product.
Two other expert witnesses reviewed subsets of the list
of Web pages that Edelman compiled. Dr. Michael T. Ryan, Director of the Rare Book and Manuscript Library and of the Center for Electronic Text and Image at the University of Pennsylvania, reviewed a list of 204 sites that Edelman forwarded to him in order to determine their appropriateness and usefulness in the library setting. Because the sites that Ryan reviewed were not selected randomly (i.e., they were chosen by plaintiffs’ counsel), his study says little about the character of the set of 6,777 sites that Edelman compiled, or the total amount of overblocking by the four filtering programs that Edelman used. Anne Lipow, a practicing librarian for more than 30 years and the director of a library consulting firm, also reviewed the same list of 204 URLs from the set that Edelman had collected for their appropriateness for a library’s collection. She categorized sites in four different levels according to their appropriateness for a public library’s collection. Again, because these URLs were not selected randomly, Lipow’s study is not particularly relevant to the total set that Edelman compiled, or to the total amount of overblocking by the four filtering programs that Edelman used. Although the methodology used
