Digital Archive Device Market - TAM Historical Societies
Follow-up research indicates that the total number of historical societies and preservation organizations in the US can be more accurately estimated at between 10,000 and 22,000, but likely closest to 16,880. Available information suggests two key reasons why this range itself is so large, and why it varies so drastically from our initial estimate (~3,500) and your client's industry-informed impression (~40,000):
1) As you suspect, many societies from the total potential pool are likely not registered or even trackable in any meaningful way due to widespread underfunding and understaffing.
2) The most recent available data indicates there are over 35,000 active museums AND historical institutions in the US (reasonably close to your client's estimate of around 40,000). However, according to the US government, only around half of those (16,880) are historical or preservation societies.
Please read on for a more thorough discussion of this data, including assumptions and limitations.
Having dealt with many small, local historical societies in the course of my research career, I share your suspicion that many of them are likely unregistered or otherwise not easily tracked. Indeed, even the American Historical Society itself claims that "No one knows for sure how many local historical societies and small museums exist in the United States today—rough estimates place the number at over 10,000."
One of the reasons why this number may be so uncertain is that "[m]any of these societies are tiny, underfunded, and understaffed"; rapidly receding government funding and declining attendance have meant that many of these societies essentially operate on a shoestring with a handful of amateur volunteers.
A more recent estimate (2015) from the US government's Institute of Museum and Library Services found that there are over 35,000 active museums in the country, with 16,880 of those being historic societies or preservation organizations. These figures were compiled from an unprecedented collection effort that drew information from a combination of IRS forms, IMLS administrative records, and data collected by a third-party vendor. You can access the most recently available data set (FY 2015 Q3) here.
To provide further verification, I searched to see if I could find any reasonably authoritative recent directories of US historical societies. The most credible source I was able to find along these lines was the Directory of Genealogical and Historical Societies, Libraries and Museums in the US and Canada, 2016. I note that the directory appears to be independently compiled, not opt-in, meaning it is likely that smaller, understaffed/underfunded societies would have a better chance of being represented here.
The cover copy for this directory indicates that it includes over 40,000 TOTAL entries ("societies, museums, historical collections and archives" in both the US AND Canada), but only just over half of those are "genealogical and historical societies" (and, again, that figures encompasses both the US and Canada). Based on this, one could reasonably assume that the number of historical societies ONLY in the US ALONE must be UNDER 22,000 (so perhaps reasonably close to the IMLS estimate of 16,880).
limitations and suggestions for further research
Two primary limitations should be noted when reviewing these findings and applying them to your work:
1) Recency. Unfortunately, overall lack of good data on this topic meant that the most authoritative sources available (AHA, IMLS) were older than we would generally provide (2012 and 2015, respectively). However, since they are likely the most accurate sources available, and from the most authoritative, relevant institutions with likely the best access to the most data, I chose to include them for your review.
2) Lack of publicly available authoritative data. Again, due to the small number of authoritative sources available and the challenge of collecting data among these disparate, underfunded institutions, the sources I was able to cite with confidence here were few. Accordingly, for these same reasons, my findings did not yield any budget- or finance-specific data that would allow me to build upon the funding portion of our previous research.
With that said, if you want to take additional measures to pinpoint absolutely the most accurate figures available for your TAM, you may find it helpful to reach out to the following people:
1) Debbie Ann Doyle, AHA Meetings Coordinator
(202) 544-2422, ext. 104
Doyle authored the cited AHA article and may be able to give you more recent/non-public AHA data, or to connect you with experts who can give you a more definitive estimate.
2) Giuliana Bullard, IMLS Press Contact
As the IMLS press contact, Bullard may be able to give you access to more recent/non-public IMLS data, or to connect you with someone at the IMLS who can.
To sum up, a second research pass indicates that the range of historical societies and preservation organizations in the US likely varies somewhere between 10,000 and 22,000, but likely closest to 16,880. A more accurate estimate could not be pinpointed or confidently triangulated due to the dearth of reliable data in this field, due to underfunding, understaffing, and declining attendance. However, it may at least give you a clearer picture of the total market, and one that is closer to your client's estimate of 40,000.