August 2017 Update to the Shared cM Project

The Shared cM Project is a collaborative data collection and analysis project created to understand the ranges of shared centiMorgans associated with various known relationships. As of August 2017, total shared cM data for more than 25,000 known relationships has been provided. To add your data, the Submission Portal is HERE. I am always collecting data, and perhaps the next update with have 50,000 or 100,000 relationships!

This August 2017 update is the second update to the original data, released in May 2015, and includes many thousands of new submissions.

There is MUCH more about the project, including histograms and company breakdowns in the PDF download.

Figure 1. The Relationship Chart

Table 1. The Cluster Chart

Sample Histogram from the Shared cM Project (all histograms available in the PDF download):

Sample of Table 3. Analysis of endogamy and company breakdown for 1C (all company breakdowns available in the PDF download):

Sample from Table 4:







10 Responses

  1. Maureen 27 August 2017 / 10:37 am

    Wow! What a tremendous amount of work. Thank you, Blaine! I used your charts all the time.

    I have a lot of known cousins now whom I want to enter as data points into your project. But…I do not remember exactly whom I have already entered (very few I think). Will you be able to weed out duplicate entries (maybe based on my email address)? I will keep track now of whom I enter…

  2. Jim Davis 27 August 2017 / 1:58 pm

    An invaluable resource, THANK YOU!

    I haven’t read the pdf yet, but is there not enough significant difference between testing company results to warrant additional charts?

    • Jim Davis 27 August 2017 / 2:01 pm

      Ignore my question (not my thanks though). Some day I’ll learn to read a bit more before I post, lol.

  3. Curtis Rogers 27 August 2017 / 9:41 pm

    I frequently refer your chart to users of GEDmatch. This update will be a big help. It is an invaluable aid to the genealogical community and an instant classic tool .

  4. Liane Jensen 31 August 2017 / 9:14 pm

    Thank you so much for the time and effort you spend generating these references for the community.

  5. Kathy Rooney 1 September 2017 / 5:38 pm

    I have put your chart on my phone! Thank you. I have one question about the average for the 4c1r, is it supposed to be 29? That makes it higher than the 4c1r. Thank you!

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