The GenTech Genealogical Data Model Project
devised a theoretical genealogical data model that also accommodates the genealogical research process.
One of useful determinations made in the GenTech model is that the same information can be recorded or presented in the exact same genealogical software package in different ways and still be completely valid and acceptable. Recognizing and embracing this is absolutely crucial to any effort to try to map genealogical data in the real world to a standardized framework. There will be differences and discrepancies, and that's ok. In fact, one of the most common shortcomings in genealogical software is in the accommodation of divergent information and theories
Download links and other references about GenTech are available at the blog, see "GenTech," //Build A Better GEDCOM// blog
Fundamental Principles of the GenTech Data Model
From the description document of the data model:
The intention of the group was to create a data model that would support the following four principles.
- The purpose of the genealogical data model is to support the genealogical research process.
- There is one and only one place to put each piece of data, and there exists a place for every piece of genealogical data.
- Some researchers will not produce all the data that rigorous pursuit of the process will produce.
- Actual software systems based on the data model should teach, encourage, remind, and assist users to follow the research process to create high quality genealogical research that can be communicated to others.
Note how different these goals are from the BetterGEDCOM project's initial project. The genealogical research process more closely encompasses a subsequent project of BetterGEDCOM we usually refer to as the genealogical workspace.
More on Assertions
[My problem with the official GENTECH Data Model is that I can't understand "assertions" from it. This may be because I can't find the full explanation, or any one of a number of explanations. However, at some point I managed to find and save this article, which makes a better job of explaining the concept. The article is pasted in as found, so the tenses, etc, are way out of date. I also have no idea whether this article was superseded by any of the formal data model. Adrian B
Dick Eastman and John Wylie, "Concepts from the GenTech Lexicon Data Model
, 15 Aug 1998, Coverpages.org, ("GenTech -- Genealogical Data Model -- Article"
: 15 Dec 2010), cites a now broken link to www.gentech.org.
The heart of the Data Model is the ASSERTION. ... The ASSERTION records the act of analyzing evidence and coming to a conclusion about that evidence. While ASSERTIONs initially address evidence, they can also address prior ASSERTIONs. We often talk in genealogy about the need to cite sources, and use evidence. The ASSERTION is the basic tool for recording that analysis. Except when addressing previous ASSERTIONs, it will usually address the lowest level of SOURCE. This is sometimes called a snippet. It may be that part of a source that addresses a particular person (what we call a PERSONA). For example, the will of a fictitious John Smith, executed on 1 May 1850, may say "...and to my daughter Polly Adams, I give $100." From this I could assert that: John had a daughter called Polly. She was alive on 1 May 1850. And that she married an Adams. From another source, my knowledge of genealogy, I could also assert that this Polly was the same person as his daughter Mary (Polly being a common nickname for Mary.) Note that these ASSERTIONs will have different levels of surety, and when combined with other ASSERTIONs that address Polly/Mary SMITH/ADAMS, will document an ancestor.
ASSERTION is linked to many other entities: SOURCE, EVENT, GROUP, PERSONA, PLACE, CHARACTERISTIC, SURETY, RESEARCHER and another ASSERTION. One can see that software that implements the Data Model would be very powerful. With all this detail recorded (or at least recordable) and linked at the lowest level, we can audit (or backtrack) on all of the hundreds of decisions we make when we enter data into our software. We can also find the decisions of those from whom we import data. Using just the links I've listed above, there are nine relationships other data may have to an ASSERTION. With the important recursive power of ASSERTIONs (that is ASSERTIONs about ASSERTIONs) this becomes the fundamental tool for documenting the genealogical process and in strengthening genealogy software: the ultimate goal of the entire project, and the reason GENTECH took on this task in the first place.