“Reasonably exhaustive” research as a process of elimination

One of the most difficult concepts to grasp, when we strive to meet the Genealogical Proof Standard, is the “reasonably exhaustive search.” This requirement demands that we conduct thorough research, scouring every possible source of relevant information touching upon our research question.

The following steps present one way to think about this requirement, as a process of reduction, beginning with a large pool of possible sources and systematically eliminating those that cannot hold relevant information.

(1) Imagine every possible source for information (meaning every written record or artifact that holds information from any location or time period throughout history). This initial pool contains billions (or more) possible records.

(2) Eliminate records that could not possibly hold information about the subject–for example, a record from ancient Egypt or medieval France could not possibly hold information relevant to the life of an African American born in the late nineteenth century in Charleston, South Carolina.

(3) Eliminate records that are unlikely to hold information about the subject–for example, records in states that neither he nor any of his family members (including hypothetical ancestors or descendants), business associates, neighbors, ever visited.

(4) Identify what records remain–what records ever existed in the times and places in which the subject lived–which of these records are currently accessible, and how and where.

So far, this process of elimination still leaves a large pool of possible sources. Examining all of them would clearly constitute exhaustive research. Exhaustive research, however, is not the standard. The standard is to conduct thorough or reasonably exhaustive research. Another way to phrase this standard would be to substitute the term “reasonably” with “rationally.” In other words, we should think rationally about our research question, our research subject, and the historical context of the problem (time and place).

(5) Systematically examine every record within this pool of potential sources. Start with the most common records from the remaining pool–census records, vital records, land records, probate records, etc. As more information about the subject becomes available you may have to add or subtract records from the pool. Be liberal in adding and conservative in subtracting. For example, a deed from 200 years later could provide a title history that includes an originally unrecorded transaction. If three census records provide three separate states of birth for the research subject, expand the pool of potential sources to include all three states.

Again, we must use our ability to think rationally and reasonably to build a case. Several points should bear directly on our use of sources:

  • Be sure to examine any record suggested by information in any examined record. So if a census record states that someone owned land or served in the military, check the land records and military records.
  • Give priority to original records and records holding primary information. This is not to say that we should ignore derivative records or authored works, nor that we should ignore secondary information. During the process of analysis and correlation of the collected evidence we will determine which information appears most reliable.
  • Ease of access is not the deciding factor when considering what sources we use. Records that do not appear online may be available on microfilm that can be rented from the Family History Library or borrowed through interlibrary loan from another repository. Original records that have not been microfilmed may be obtained through the mail directly from the repository or through the use of a local hired agent.

Finally, how do we know when we have completed the process? Is it when every single item on the list has been crossed off?

Sometimes. Again, we have to use our reason and rational thought. If we are trying to identify the father of John Smith and we have conclusive evidence that his father was James, then we can stop the search. For example, suppose we have found the following records through our initial research:

  • A death certificate identifying John Smith’s father as James Smith–the informant being John’s eldest son William;
  • A marriage record, informed by John Smith himself, identifying John’s father as James Smith;
  • Three federal census records, in which John was aged 2 years, 12 years, and 22 years, respectively, living in households headed by James Smith;
  • A will written by James Smith in which he identifies his son John Smith;
  • A church baptismal record that provides John Smith’s date of birth and identifies his father as James Smith;
  • A tombstone, containing the date of birth as presented in the baptismal record and the date of death as presented in the death certificate, thus connecting the two records as pertaining to the same individual.

It is probably safe, in this scenario, to stop searching. We are unlikely to locate further information that will contradict the conclusion that John Smith was the son of James Smith. We do not have 100% certainty of course. A court record or DNA testing could reveal that John Smith had been adopted. Perhaps it is reasonably (and therefore necessary) to search these additional records, depending on the collected evidence in the case. On the other hand, it may exceed the standard, depending on the collected evidence, and therefore be unnecessary. Some of the other relevant evidence that should be considered in this case are the norms of the location, family oral tradition (if any), the socioeconomic status of the family, the birth order of John among the other children of James and his wife, etc.

The successful genealogist must have a developed sense of reason. Most problems that we encounter will not be as clear-cut and simple as the case of John Smith son of James Smith. Far more often we will encounter families where these relatively reliable sources of direct evidence were never created or do not survive. These cases require thoughtful and insightful use of vast amounts of indirect evidence. For these more complex cases, we will have to search many more sources to meet the standard of reasonably exhaustive. We often have to collect and correlate material relevant to every aspect of our subject’s life as well as investigating the lives (and records) of known family members and associates. We must be able to recognize when we have examined enough evidence to make a reasoned conclusion possible.

12 thoughts on ““Reasonably exhaustive” research as a process of elimination

  1. Michael, this is an excellent post. I am putting this into my file to refer to later, for you have taken it down to a personal level instead of just finding the names and dates of ancestors.

    This is wonderful!

  2. The John Smith example illustrates the perils of relying on the array of documentary evidence all of which could be expected to follow if John had been conceived by a different man, either without James being aware or agreeing to conceal that fact.

    Helen Leary wrote in http://www.bcgcertification.org/skillbuilders/learyevidencepf.html that “Because we cannot be absolutely certain of genealogical facts without the aid of DNA tests, the statements we make are assertions of what we believe to be true.” When DNA tests are relevant, and they are now entirely practicable, there is no longer any legitimate reason to exclude them from a reasonably exhaustive search and the evidence supporting what we believe to be true.

    • John,
      You’ll note that I acknowledged the possibility that DNA results could potentially overturn the conclusion. However, suppose that John Smith was an only child born in 1765, and had only daughters who themselves had only daughters. No DNA test on the market today would provide any relevant evidence in this case. We must therefore rely on the documentary evidence, which is generally conclusive.

  3. While I have seen estimates of non-paternity events in each male generation of 5% used for purposes of illustration, which when extrapolated would give a 40% probability of such an event within 10 generations of a male line, there is no reliable way that I have seen to accurately benchmark such probabilities in general, though there may be for certain populations.

    It should be noted that many possible male lines may continue to the present day from such a John Smith, and I would think that more than one would have to be tested since a break may only be in one such sub-line. Furthermore there is the problem that such DNA determinations rely on comparisons with the putative lines of other, different and same surname lines, which may have been shoddily researched.

    Also, and this comment is not aimed at the commentators above, I would suspect that many who advocate DNA testing being an essential part of a reasonably exhaustive search do not both test more than one sub-line, and also perform a truly reasonably exhaustive search in the records, instead seeing DNA as a shortcut to avoid same.

  4. Thank you for an outstanding and very understandable explanation. I’m going to include this as a reference in the presentation I am preparing for our local society on reasonably exhaustive research.

  5. Pingback: What Constitutes a “Reasonably Exhaustive” Search? | Genealogy Update

  6. Pingback: Two pension cards, one cousin George Frederick Ashley…solving a genealogical puzzle… – writing my past

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