From the Library Journal article:
Toledo-Lucas County, OH, Public Library conducted a study to calculate the library’s return on investment. The study computed the value of the library’s services in two different ways: by economic impact analysis, which yielded a figure of $118.3 million, and by adding up the value of the services provided by the library, which totaled $136.1 million. (The discrepancy is because the first method includes only direct effects; the second, both direct and indirect.)
The study, conducted by Dr. Oleg A. Smirnov, Associate Professor at the Department of Economics, The University of Toledo, found that the library’s return on investment is 2.86. In other words, every dollar invested in the library returns $2.86 worth of value to the community. That rate is comparable to other libraries around the country: According to the study, the ROI for Indiana Public Libraries is 2.38; for Carnegie Library, Pittsburgh, PA, is 3.0; and for Cleveland Public Library in 2009, 2.7.
Toledo Library Studies Return on Investment
Source: Meredith Schwartz, Library Journal, July 31, 2012