The Shared cM Project (ScP) is a collaborative data collection and analysis project created to understand the ranges of shared cM associated with various known relationships. The ScP has been very successful, with more than 60,000 submissions from amazing genealogists like YOU! To add your data, the Submission Portal is HERE. I am always collecting data, and hopefully the next update will have more than 100,000 submissions!
The full PDF for Version 4.0 of the Shared cM Project is here and it is ESSENTIAL that you read the full PDF for all the details from the project: The Shared cM Project Version 4.0 (March 2020).
Today, the most recent version of the ScP, Version 4.0, goes live. I’ve taken nearly 60,000 submissions and analyzed the data for almost 50 different relationships. For each relationship the 100s or 1000s of submissions were analyzed to remove outliers, to provide minimum, maximum, average, and standard deviation values, and to generate a histogram for the distribution of the submissions. Here are some of the other differences between this new Version 4.0 and the previous version (click to enlarge):
Note that there ARE going to be some big changes to the minimum, maximum, and average values for some relationships compared to the previous version, as more data equals better data. From page 54 of the full PDF:
There are many changes to the minimum, average, and maximum values for relationships in Version 4.0 of the Shared cM Project relative to the prior Version 3.0. As the number of submissions for a relationship grows, the distribution of cM values for that relationship is more clearly defined. This allows for improved definition and elimination of outliers for each relationship. In some cases, the very large increase in submissions moved the minimum and/or maximum values further outward for a broader distribution in this version, and in other cases it moved the minimum and/or maximum values inward for a tighter distribution in this version.
There’s a table on pages 55 and 56 that show the percentage change for the minimum, maximum, and average values for the different relationships.
There is of course a brand new Relationship Chart with all of the new ranges and averages (click to enlarge):
Be sure to look for the gray bar at the top of the graphic that says “Version 4.0 (March 2020).” That’s how you’ll know you’re using the most recent version of the chart.
There are many more graphs and charts in the full PDF, so be sure to check it out!
The Interactive Shared cM Project at DNA Painter
In addition to the full report and the updated Relationship Chart, there’s another incredibly valuable aspect of this update. Since September 2017, Jonny Perl has hosted a web-based version of the ScP at DNA Painter. It allows you to put in a cM value and see which relationships that cM value falls into.
Jonny has graciously updated the tool with the new numbers, AND has added new features! If you click a relationship box, the histogram for that relationship will show in a pop-up! The histograms are now available for every relationship in the Relationship Chart, without having to refer back to the full ScP report.
Jonny has a blog post about the update with much more information at “Introducing the updated shared cM tool.”
It looks amazing and contains an incredible amount of information right at your fingertips. Thank you Jonny!
Obviously, this project couldn’t happen without YOU! Every person that has ever submitted even a single relationship has helped create this tool for the benefit of the entire community. And I am will continue to collect data indefinitely, so feel free to visit the Submission Portal HERE. Again, a huge thank you to each and every one of you.
Please also be sure to check out page 4 of the full ScP report for some special thank yous.
I hope you enjoy the update! Thank you!