One major concern when using my genealogy software program is that I can later export all the data that I entered to GEDCOM. This could be for the purpose of backup, giving to someone else who uses a different program, or possibly transferring from one program to another.
I do understand that GEDCOM does not transfer perfectly because some programs don't write it correctly and others do not read it correctly. But my concern here is whether or not all the data I enter into my program will be exported by my program into GEDCOM. If the data does not export in the first place, then it will be impossible to transfer it.
The test would be to use the program's data entry forms to put dummy data into every possible input field (maybe use the name of the input field so you can identify it again in the GEDCOM) and then see what does not make it into the GEDCOM. It would be necessary to locate every single input form, tab and window in the program where data can be entered.
I think it is very important to know what fields do not get exported to GEDCOM in the program I use. Knowing the fields that do not export will allow me to avoid bothering to enter any data into the fields.
If I decide to switch programs, I would like to see a comparison of how complete the GEDCOM exports are of those programs before I move to them.
Have there been any data "coverage" tests done on genealogy programs? Are there any vendors who have done this test on their own program and have shown that 100% of what is can be entered into it will be exported to GEDCOM?
Follow-up Dec 3: ColeValleyGirl pointed out in her comment on Arnold's answer that Family Historian stores all its data in a GEDCOM file. I checked and in fact there are no auxiliary files used. So FH is a case where 100% of its data is in the GEDCOM and it is safe to enter any information into Family Historian and not worry that you won't be able to get it out again.
The same would hold true for any program that solely uses GEDCOM for its file format. One other program I can think of that does this is Tom Wetmore's program Lifelines.
Of course, a program using GEDCOM as a database would have to either:
- Export the data for non-standard features using many user-defined tags and non-GEDCOM standard structures,
- Not include many non-standard features, or
- Do the bad thing and allow users to input the data for those features, but save them outside the GEDCOM.
1 and 2 are okay. 3 would be bad. Family Historian tends to do the number 2 thing excluding many of the useful features other programs have, such as Place-level data or citation templates.
So Family Historian and Lifelines and other such programs that use GEDCOM as their entire database would be good programs to use without the worry of entering data that will not export again.
Now that we know this, I'm still interested in knowing if anyone has done this coverage test on programs that store their data in their own proprietary database format.