Dear Jim, I agree that your cup is at least half full and is it almost completely full for your matches over 10 cMs in length. The overall percentage of my wife's and my matches that were IBD where the match was 5 cMs or longer was 69%. If I change the match criteria to those that 23andMe uses (7 cMs and 700 SNPs), then the overall the overall percentage of my wife's and my matches that were IBD was 84.6% (137/162). Everyone of the matches that were IBD that were between 3.5 and 5 cMs in length also had a larger matching segment that was IBD that was over 5 cMs. Sincerely, Tim -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Jim Bartlett Sent: Monday, January 09, 2012 3:46 AM To: [email protected] Subject: Re: [AUTOSOMAL-DNA] SUBJECT: How do you work a 5 way FF match with few clues ? Tim Even without my coffee yet, I can look at this data and say my cup is half full;>) As a genealogist, there's gold in them thar hills! Even at 4cM 1/6 are IBD. The FTDNA cutoff of 7.7cM still gives at least a 50/50 chance (probably 75%, if you draw the curve for your data), or better, that each one they report is IBD. Or 3 of 4 are probably IBD. I'm not that good with statistics. My estimate that 3/4 of FF matches are IBD, is based on the 7.7cM or more large segment each one has. I wonder how many of the other 1/4 have at least one of the smaller segments that is IBD? I thought the FTDNA algorithm included other factors, that increased the probability that our FF matches were really cousins - this would be the icing on the cake for me (and really jazz up my presentations) Tim, could you look at your data again, and see what percentage of your FF matches have no IBD segments at all?