Q. We're reviewing our policies on overdue fines and are looking for resources to guide our investigations. What's out there?
A. Ideally, of course, everyone borrowing a book from a library would return it on time, or even a little early, so other library users would be able to use the book. The reality is different, so libraries developed the economic incentive of the overdue fine: no cost if you return on time. We don't know how much libraries, as a whole, collect in fines, as both major statistical reports (IMLS' Public Libraries in the United States and PLA's Public Library Data Service Statistical Report) roll the amount collected as fines in with "other" sources of revenue, such as monetary gifts and donations, interest, other fees for library services, or grants--all of these totaling about 8% of library revenues, nationally.
Besides fines, libraries use other mechanisms to get their books back, including amnesty periods, where fines of any size are waived to get materials back into circulation--and perhaps reform a library user into an active user again.
Although the American Library Association does establish some policy statements having to do with "National Information Services and Responsibilities", including policy 50.3, Free Access to Information, operational policies, including those for how and when to collect fines, are established by the local libraries, through their governing boards. Several state libraries and Webjunction have assembled collections of sample policies--and these are as varied as the libraries preparing them. Yet more library policies on fines may be found with a pre-structured web search.
For additional background reading, we've gathered together resources on issues of circulation management and fines and overdues.