Ahern, Ahearn or Van Horn?

​One of these names is not like the others.  Can you tell which one?   If you guessed Van Horn, guess again.  It’s Ahern.  Huh? Yeah… Ahern.
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For a long time (far too long!) I assumed when I typed the surname, AHERN, into the search boxes on FamilySearch.org that it would pick up not just AHERN, but also some of the common variants such as AHEARN and AHERNE.  But recently I discovered that for some inexplicable reason AHERN garners its own set of results.

I did some searches in two New Jersey record sets – “New Jersey Births and Christenings, 1660-1980” and “New Jersey, Births, 1670-1980,” limiting the results to a birthplace of Somerset County, New Jersey and birth years between 1847 and 1900.  I was looking for birth records of the children and grandchildren of my great-great grandfather, James AHERN, and his three brothers, all immigrants from Ireland.

With the search for AHERN I received 13 results.  In each of the results the surname of the child and the father was indexed with the identical spelling, AHERN.  Closer examination of these results, looking at birth and/or christening dates and parents’ names revealed some of them were duplicates of others in the batch of 13 records.  Eliminating the duplicates, I discovered six unique children. 

When I typed in AHEARN in the search box, I received 67 results.  Eliminating the duplicates, I narrowed it to 45 unique children.  Not one of those results duplicated any of the results in the AHERN search.  But if I searched for AHERNE, HEARN or HERN, I received the exact same list of 67 results.  The 67 results included surnames HORN, HERN, VAN HORN, VANHORN, HOHN, HORNE, and O’HEARN.  With each of these alternate searches, the resulting names appeared in a slightly different order, but they were the same results and none of them included any from the original AHERN search. 

I don’t know what comprises the search algorithm used by FamilySearch.org, and I have not found any guidance on their website explaining it.  But my takeaway from this exercise is that I should not make any assumptions about what alternate spellings FamilySearch searches for.  Read the results list.  If you don’t see at least one example of each alternate spelling you know could be there, experiment with all known surname variants.