Important 2019 updates:
December 2019: GEDmatch has been purchased by a forensic testing company that works with law enforcement. As usual, The Legal Genealogist Judy G. Russell did an excellent job of explaining things. I strongly encourage you to read the announcement and Judy’s explanation so you can make the decision that’s best for you about whether to use GEDmatch—and so you can speak with any relatives whose DNA you may have uploaded to GEDmatch so THEY can decide what they want done with their DNA.
May 2019: GEDmatch opt-in for law enforcement use
What is GEDmatch?
GEDmatch is a mostly-free online tool where anyone with autosomal DNA test results from 23andMe, FTDNA, and AncestryDNA can meet and share information. All you need to do is download your data from your testing company and upload it into your newly created GEDmatch account.
GEDmatch is set up just like your testing company in that it provides two kinds of reports: ethnicity results and a match list. Remember that ethnicity results, meaning those pie charts that report you are 15% Italian and 32% Irish, are based on two factors: a reference population and fancy math. GEDmatch has gathered data from multiple academic sources to provide you with several different iterations of ethnicity reports. This is like getting a second (and third and fourth, etc) opinion on a science that is still emerging. It is a fun exercise, but will likely not impact your genealogy research very much.
Your GEDmatch match list
The more important match list allows you to see genetic cousins who have tested at other companies and who have entered their results into GEDmatch. This means GEDmatch has the potential to expand your pool of genetic cousins, increasing your chances of finding someone to help you track down that missing ancestor.
Many also flock to GEDmatch because they were tested at AncestryDNA and thus do not have access to a chromosome browser:
A chromosome browser allows you to visualize the physical locations that you share with someone else. Some find this to be a helpful tool when analyzing their DNA matches, though in my opinion it is not essential.
More great GEDmatch DNA tools
GEDmatch also has some great genealogy features that let you analyze your pedigree against someone else’s, as well as the ability to search all the pedigree charts in their system so you can look specifically for a descendant of a particular relative.
However, even with all of these great features, GEDmatch is still yet another website you have to navigate, and with that will be a learning curve, and certainly some frustration. So, is it worth it? If you are fairly comfortable with the website where you were tested, and you are feeling both curious and patient, I say go for it.
Originally published August 2016 on genealogygems.com.