Ed -- The following is in response to the CTPP listserve question about the request for Social Security Numbers on some decennial census questionnaires. Randall Neugebauer of the Planning, Research, and Evaluation Division, U.S. Census Bureau, provided me with the following information on the SSN, Privacy Attitudes, and Notification (SPAN) experiment. The SPAN is one of three panel experiments taking place concurrently with Census 2000. Each experiment looks at innovative methodologies and/or technologies that might be considered for 2010. Use of administrative records is one such notion being considered and tied to it is the collection and use of the SSN as a "match" key. The SPAN gathers data as to respondent behavior in providing the SSN. A total of 21,000 households of the mailout/mailback universe received a short form requesting the SSN. The cover letter, however, explains that providing it is voluntary. Attached is a current list of Frequently Asked Questions (FAQs) for the SPAN experiment, which I believe will address your immediate concerns. These FAQs are being used by our telephone questionnaire assistance operators to field questions on the SSN and other topics related to the SPAN experiment. (Ed's note: I converted the file to an RTF format. if your have problems with it let me know.)