Dear Seppo; My coauthors and I have been using "Unconfounded Mechanism" for survey sampling situations, which corresponds to MAR under a super-population set-up. This term was also coined by Rubin (1983) but we used it in a little bit narrower sense. Our framework is conditional on a given sample, that is, the unconfounded response mechanism is that the response probability is independent of auxiliary variables observed for the whole sample (for more detail see Lee, Rancourt, and Sarndal, 1994, JOS).
Best, Hyunshik Lee, Ph.D. Westat 1650 Research Blvd. Rockville, MD 20850 E-mail: [email protected] Tel: 301-610-5112 Fax: 301-294-2034 -----Original Message----- From: Laaksonen Seppo [mailto:[email protected]] Sent: Thursday, March 29, 2001 5:39 AM To: [email protected] Subject: IMPUTE: MAR I do not like about the term MAR, missing at random. Of course, when it has been defined, there are no problems. But the direct interpretation of that term is confusing, since missingness is not random in this case but conditionally in some sense. The term should be something like missing at random conditionally (MARC) or MAR according to covariates. I am not fully satisfied to those terms. What do you prefer? Best regards Seppo Laaksonen
