What public libraries do is changing. We’ve known that anecdotally for some time. We have a lot of theorizing that we are or soon will change. What follows is proof.
Compared to 19 years ago, public libraries are seeing about the same amount of circulation per population served. However, we have a lot more people coming in the door, and as a consequence our circulation per visit has declined significantly.
I used the national library statistic numbers retrieved from the Institute of Museum and Library Service (IMLS) for 1992 and 2008. Those are, respectively, the oldest and most recent data sets available. From those I extracted the LSA population, the total visits, and the total circulation. I removed all libraries which had zero circulation or population to avoid divide by zero errors. For each library I then generated the visits per capita, circulation per capita, and circulation per visit. I then determined the mean and median of those three results. Finally, I determined the percent change from 1992 to 2008 in each result.
1992 | 2008 | % change | |
Mean visits per capita | 4.63 | 6.23 | 34.60% |
Median visits per capita | 3.58 | 4.9 | 36.90% |
Mean circ per capita | 7.87 | 8.44 | 7.20% |
Median circ per capita | 6.64 | 6.57 | -1.10% |
Mean circ per visit | 2.78 | 1.6 | -42.40% |
Median circ per visit | 1.78 | 1.36 | -23.60% |
As you can see, the number of visitors to libraries has increased by a third since 1992. Since circulation hasn’t changed significantly libraries are circulating significantly fewer items per visitor.
The key point to this is that one common anecdote is untrue. Public libraries are not becoming less used by the community. However, the increased use is not in the traditional area of circulation. Anecdotally the increased use is from computers. Henderson’s 1999 report indicates this might be true, and I intend to use the 2008 numbers to see if the trends he identified continued.
(I am bothered by the large difference between median and mean for the 1992 numbers. The reason is apparent in looking at the raw numbers in that some libraries have extraordinarily high visits for their sizes. A more complete treatment would be necessary to determine if these are flukes or typical. Regardless of statistic chosen, however, the trend from 1992 to 2008 is obvious and unclouded, and so for the purpose of this blog the discrepancy does not need resolved.)