Analysis & Correlation

Analysis & Correlation: Digging Deep

The GPS requires thorough analysis and correlation of information. Understanding some basic terminology is necessary to effectively evaluate your research findings.


Part of developing your research plan included locating resources where you might conduct your search. Resources are places or media that house sources. Resources include libraries, repositories, courthouses, microfilm, the Internet.


Sources are the “containers” for the information you are seeking. You task is to identify the most-likely sources for the information you need, then locate the best possible resources for accessing those sources.

Three broad categories of sources exist:

  • An original source contributes written, oral or visual information not derived from a prior record. Usually (but not always) these are created close to the time of the event. Examples: death certificates, wills, land deeds.
  • A derivative source contributes information that was copied, abstracted or extracted from an original, previously existing source. These sources should be considered finding aids that lead to the original source. Examples are databases and indexes.
  • Authored works are created by someone who draws on multiple sources and presents his own conclusions. Examples: biographies, histories, blogs, etc.


Sources contain information. Information is all the different pieces of data the source provides. Not all of that information may be relevant to answering your research question.

  • Primary information, usually created close to the time of the event, comes from someone with first-hand knowledge. Generally considered more reliable, it still may be inaccurate. Example: a marriage record, created at the time, is primary information for the names of the couple and their marriage date.
  • Secondary information is usually created after the fact, by an informant with no first-hand knowledge of the event. Example: a death record may provide the birth date of the deceased, but the informant may not have been present (or even alive!) at the time of the birth, so would have only second-hand knowledge of the event.
  • Indeterminable information is just that—you can’t tell whether the information is primary or secondary. Example: with the exception of 1940, census records do not specify the informant for data provided to the enumerator. It could be a family member, landlord, or neighbor. Quality of this information cannot be reliably determined.


Evidence is comprised of the relevant pieces of data that gleaned from the information contained in the source.

  • Direct evidence answers your question outright, with no additional evidence needed to support a conclusion. Direct evidence may or may not be correct. Example: A gravestone may directly state a birth date and death date for the deceased. But we know sometimes gravestones are wrong!
  • Indirect evidence provides clues to answering your question, but more evidence is needed to support a conclusion. Example: no record states the relationship of your ancestor to his parents. But if you can find evidence to support his relationship to his siblings, and then find evidence to connect the siblings to the parents, you can build a case that your ancestor shared those same parents.
  • Negative evidence occurs when the source does not provide any evidence to answer your question. Negative evidence can be important, too. Example: Your ancestor is found in tax records for 1857 but not for 1858. Why not? The negative evidence may suggest a migration or death, and certainly indicates more research is needed.

Understanding resources, sources, information and evidence provides a solid foundation for the research process.


Once you’ve collected the evidence your sources provide, you’ll need to organize, then compare and contrast the findings. Many tools are available—experiment until you find what is most helpful for you:

Tools for Correlation

  • Arrange information chronologically in a time line
  • Arrange information by given names
  • Arrange information by location, religion, neighborhood, or any category that helps sort identities
  • Use tables or spreadsheets for correlations
  • Use discussions, figures, tables, lists, or a combination to show correlations of agreement and disagreement

Resolve Contradictions

Comparing results may reveal contradictions—continue to evaluate your sources for reliability. Broaden the field to locate new sources that might clarify or add weight to the argument for or against a particular result. Research the “FAN” club—friends, neighbors and associates of your ancestor whose own lives may shed light on your dilemma.

Reaching Conclusions—or Not!

Evidence is a tentative answer to a genealogical question. Testing that answer with analysis and correlation leads to a hypothesis. If the hypothesis passes our tests, it becomes a conclusion. Conclusions should be weighed against other conclusions before reaching a final determination.

If conflicts remain unresolved, what are your options? You might continue to research new and different types of sources or continue to explore the “FANS.” Or you might decide to set your work aside—perhaps new avenues of exploration will present themselves with the passage of time. A third option is to present your findings “as is,” explain your research, the contradictions, and why you’re stuck. That’s OK too—genealogy is a journey; somewhere down the road lies the answer you seek.