Patti, The raw DNA data from each of the 3 companies is compatible. The algorithms 23andMe, FTDNA and GEDmatch use (using data from any company) result in almost identical Matches and shared segments - only slight deviations, occasionally. The big picture is that they are all the same. However, AncestryDNA has a significantly different system. We have found some large shared segments and Matches that AncestryDNA doesn't report; and a LOT of AncestryDNA Matches that are based on relatively small (5-7cM) segments that most of us find are IBS, but AncestryDNA insists are valid based on their "population" phasing. For me, I rely on shared segments from the other companies; and use AncestryDNA Matches and shared segments when there is no other data - a recognize that the data may not be compatible. The AncestryDNA Trees, Hints, etc are helpful. Jim - www.segmentology.org > On Dec 28, 2015, at 9:58 AM, Patti Easton via <genealogy-dna@rootsweb.com> wrote: > > Good Day- > > > > Can someone explain to me why there is a significant variation in cM match > amounts from Ancestry to gedmatch, when it is the same Ancestry kit that was > uploaded to gedmatch? For instance, I have a match that shows 34cM and 3 > segments on Ancestry, but records as 46.3 cM on 3 segments on gedmatch. > Granted it is a small match, but that is a variance of 12 cM, more than 25%. > If this is how it reports, does the variance % decrease for larger matches? > > > > Thank you! > > Regards, > > Patti Easton > > > > > ------------------------------- > To unsubscribe from the list, please send an email to GENEALOGY-DNA-request@rootsweb.com with the word 'unsubscribe' without the quotes in the subject and the body of the message