Randy over at Genea-Musings has posted another Saturday Night Genealogy Fun Challenge : determining your ancestral number. The challenge asks you to take a hard look at your ahnentafel and determine how complete your family tree really is. The challenge was based on a post by Christa Cowen entitled Family History All Done : What's Your Number?
The number of ancestors doubles each generation, and by 10 generations you have 1023 ancestors. By going back through the generations and counting how many ancestors have been identified in each generation you can get an idea of the completeness of your family tree.
After 25 years of amateur research, my number is 40.96%. I do really well until the 5th generation, where I have an illegitimacy. I hold my own for another generation at 93.75 percent, but start to fall off in the 7th and 8th generations.
Pedigree collapse becomes apparent by the 9th and 10th generation, particularly on my paternal side.
All in all, a fun exercise to see just how much more there is to research.
Click on the chart below to enlarge.