Reliability Assessments

When publishing a family tree online it is useful for visitors to be able to quickly and accurately assess the validity of the claims being made. Gigatrees5 automatically calculates the reliability assessment for every claim using several pieces of data including, the source category defined for the referenced sources, the GEDCOM source reference quality tag ( QUAY ) defined within the source references for the claim, and the vendor specific GEDCOM source type tag ( _TYPE ) defined within the source itself. Gigatrees5 will display the calculated reliability assessment alongside each claim.

Gigatrees5 defines several levels of reliability: unsupported, estimated, unreliable, uncertain, proposed, reported, supported, probable, certain, questionable, proven and impossible. When multiple sources are referenced for a claim, the source with the best quality is used. If a source reference is found for a claim, but no source or source reference quality is defined, the reliability assessment will be set to uncertain. If the claim is an estimated birth year, the reliability assessment will be set to estimated. If the claim is not a birth date estimate, and no source reference is found for the claim, the reliability assessment will be set to unsupported.

Biological relationships, including child-parent relationships, are treated as claims (because they are) and are accompanied by reliability assessments. If you have not already done so, you may want to add source references to your parental association claims.

On occasion, the calculated reliability assessment may be inappropriate for the claim being made. This can be caused by improper source categorization or failure to reference all the available sources. It can also be caused by a reliable source making a unreliable claim. To override these, Gigatrees5 supports setting the reliability assessment manually to any claim by using the standard GEDCOM note tag ( NOTE ).

0 @I1@ INDI
1 BIRT
2 DATE 1 JAN 1900
2 NOTE proven

Overriding reliability assessments is the only method for directly indicating that a claim is disproven or impossible.

The reliability assessment strings are translatable so that you can use strings in your own language.

When displayed, claims always show the "best" assessment, which implies an order of precedence. In general the order of precedence always degrades from the most certain to the least certain. As shown in the table below, there are four GEDCOM data fields that affect order, the reliability assessment override field ( NOTE ) described above, the presence of a source reference ( SOUR@ ) for the claim, the source category ( _QUAL ), and the standard GEDCOM source reference quality tag ( QUAY ). Note that not all of the defined reliability assessment strings described above will be automatically determined, but can still be set using the reliability assessment override tag.

To prevent Gigatrees5 from making exaggerated reliability assessment determinations, sources that contain multiple types of evidence, should set the source category to the quality associated with the least reliable evidence. You can also break up your source into multiple sources, one for each type of evidence.

In the table below, an "x" indicates that a field must be present. An empty field indicates the the value of the field has less precedence or does not matter.

NOTE        SOUR@  category    type     QUAY  reliability
------ ---- -------- ---- ---- ---------
estimated [calculated]
[value] [value]
x 0 questionable
x dna proven
x 3 certain
x primary certain
x original certain
x 2 probable
x secondary probable
x transcript probable
x copy probable
x abstract probable
x research supported
x memoir reported
x 1 proposed
x derivative proposed
x unknown uncertain
x negative unreliable
x [value] [value]
x uncertain
unsupported

When there is no other information available to determine the reliability assessment, Gigatrees5 makes one last ditch effort by looking at the source's type ( @SOUR.TYPE or @SOUR._TYPE ) field. This is a non-standard GEDCOM field, but is used by several popular genealogy applications.