Tuesday, February 6, 2007

California Death Index - Use Rootsweb not Ancestry!

I posted yesterday about not being able to find Joseph Carr in the CA Death Index (1940-1997) on www.ancestry.com, but I did find him in the CA Death Index (1940-1997) at http://vitals.rootsweb.com/ca/death/search.cgi on Rootsweb.

Drew Smith commented on the discrepancy, counted the total number on both sites, and is going to ask Ancestry about it.

Curiosity drove me to do some investigating, and here is what I found:

* There are 8,194,784 entries in the Ancestry database (3,812,744 females and 4,382,040 males) , and 9,366,786 in the Rootsweb database (4,235,715 females, 5,130,939 males, 132 others). That is a ratio of 0.875 of Ancestry to Rootsweb entries, or 1 in 8 entries that are on Rootsweb and not on Ancestry. Fascinating. Troubling.

* For San Diego County**, there are 561,375 on Ancestry and 629,816 on Rootsweb (0.891 ratio)

* For Los Angeles County**, there are 2,822,607 on Ancestry and 3,272,998 on Rootsweb (0.862 ratio)

* For San Francisco County**, there are 479,162 on Ancestry and 557,720 on Rootsweb (0.859 ratio)

* For Fresno County, there are 188,076 on Ancestry and 216,388 on Rootsweb (0.869 ratio)

* For Del Norte County, there are 8,123 on Ancestry and 9,078 on Rootsweb (0.895 ratio)

* For Inyo County, there are 9,832 on Ancestry and 11,132 on Rootsweb (0.883 ratio)

For the counties denoted ** above, the Rootsweb database separates them into City and County components, while the Ancestry database includes both in one listing and doesn't denote city or county in its results.

I only looked at 10 counties (out of 58, not all are above) and the ratios are all in the 0.85 to 0.90 range.

I then checked the first 100 entries on the Inyo County lists for Ancestry and Rootsweb side by side. I found that:

1) Ancestry missed several entries that are on the Rootsweb list (e.g., Charles L. Abbott, the second entry on Rootsweb). The misses seem to be random.

2) Ancestry had several entries out of alphabetical order (e.g., Acker after Ackerman)

3) Rootsweb had a few duplicate entries (e.g., Russell C. Abbott), while Ancestry had only one entry for that person.

A more detailed survey might reveal more differences, but I judged it to be an essentially non-productive effort.

My recommendation to ALL genealogy researchers is to use the FREE California Death Index database on Rootsweb at http://vitals.rootsweb.com/ca/death/search.cgi and not the index at Ancestry.com for their research of California Deaths.

Questions come to my mind:

1) Did Ancestry digitize their own index of the California Death Index or did they use an existing computer database? If so, what resource did they use?

2) Are there other Ancestry online databases with these same problems? It might be a good idea to compare some of the other vital record indexes available at Ancestry and at other web sites.

We know that the Ancestry census databases are different from the HQO/Genealogy.com census indexes, and the reason for the differences are fairly obvious - mainly different people trying to read handwriting.

I do really appreciate the online resources at Ancestry.com, but I am now a bit skeptical of the "purity" of the databases.


Hugh W said...

even more important Rootsweb is a freebie

(paid for by ancestry subscribers)

hugh W

Craig Manson said...

I do a lot of work with the CA death index (among other things, I use it to create a maiden name index), so this is very troubling. I will use Rootsweb now. Thanks for the good info.

. said...

Fascinating stats--thanks for the headsup!