title: How does R's clogit (Survival package) function handle incomplete groups?
body: <p>I have matched case control data - 1 case matched to two controls. My N is ~ 580 and I have 168 matched groups. About 14 of these groups are missing 1-2 members, with cases and/or controls missing. I've been trying to figure out how R's clogit function - from the Survival package - handles these missing groups, if at all, and haven't found anything. </p>