Monday, September 8, 2008

OneWorldTree® Dendrology 101: OneWorldTree®

OneWorldTree (OWT), like FamilySearch's Ancestral File, was an attempt to build a single, unified pedigree containing all of the people and data from's records. Computers were used to identify and merge records about the same person. When it was released in April 2004 it contained all the families that could be identified in the 1930 census plus trees submitted to Ancestry World Tree (AWT) through the website. Initial plans were to merge in all of's records, but as time passed, I believe the only other records added were AWT trees from RootsWeb and maybe family trees from World Family Tree (WFT).

The OWT database requires an subscription to use and has two different modes: classic and read-only. The classic mode allows users to clean up their view of the OWT data, adding individuals and data, choosing among conflicting parents and spouses, linking additional records to individuals and otherwise fixing mistakes. However, customers' customizations were visible only to themselves. Some of the initial messaging to customers said that user corrections and additions would periodically be incorporated into the globally-visible tree, but it was later discovered that the website Terms and Conditions did not give the right to do so, so this plan was abandoned.

OneWorldTree classic mode
OneWorldTree classic mode

When Ancestry Member Trees became available, the ability to make changes in OWT was removed, rendering it read-only to new users. Classic mode was retained for those customers that had previously made customizations. provided a migration path so these customers could move their OWT additions into a Member Tree. As far as I know, since that time has ceased improving OWT.

OneWorldTree read-only mode
OneWorldTree read-only mode; compare to classic mode

In my opinion, like Ancestral File before it and New FamilySearch's Family Tree after it, OWT suffers from unmerged-duplicates, incorrect merges, endless loops and known inaccuracies. Still, is able to use it as the basis for showing users' relations to famous individuals.


  1. I do wish ancestry would stop using OWT as a 'source'. When I'm looking for info for a person, I do not consider OWT as a reliable source and it is a waste of time to open a sourced tree only to find the source is not a census or historical document, but is instead the OWT. OWT might be considered at hint but it is IMHO not a reliable source.

  2. (Formerly Ancestry Insider) said: ". . . . OWT suffers from unmerged-duplicates, incorrect merges, endless loops and known inaccuracies."

    OWT is composed of Trees that mostly are not evidence-based. Many of the user-submitted Trees have slight variations from each other for a given purported family group. Some users even have added evidentiary notes and documents. The computer errors you speak of don't make it that much worse than the original data. How the computer selected which version or which fragment of a given Tree into OWT is a mystery.

  3. I FULLY agree with anonymous ...

    OWT is fully of errors, duplications and is known to be totally inaccurate ... why does continue push this on us as sources?

    The "View People with hints" is a nice feature in AMT, but I'd far prefer to see the ability to opt-out of seeing OWT "sources" -- at the very least -- when given hints, clarify which are from valid sources such as census reports or social security records and which are from OWT.

    I am seeing far too many hints from family trees who "source" only OWT. This is a total waste of time for those of us who care about accuracy in our records.

  4. Besides the pervasive factual errors that others have described, OWT suffers from ethical issues as well. Individuals who innocently submitted their trees to Rootsweb WorldConnect, under guarantee that they would not be copied, sold or merged with others (Rootsweb Review, Vol. 3, No. 5, 2 February 2000), now find them included in OWT which Ancestry charges people a minimum of $155 a year to see. Once Ancestry latches onto your data you lose control over it. If you later find errors and want to make changes, too bad, you're out of luck. You can change the WC tree, but the errors will have already propagated to OWT.

  5. Iam just wanting to know about my family history. most of them are from Ill. and I don't have to many left that I know of.The other part of family are in berkely calif, or there abouts.Iam in kentucky, now so it would be nice to know if I have anyfamily left.thanks patricia beach.