To map a collection means asking: Which coded characteristics in the cataloging record will find the greatest number and most relevant resources that support the research and teaching of a given subject field?
In cases of collection analysis, this means ignoring overlap. Unlike budget analysis, wherein one cannot count and allocate more funds than are available, collection analysis can allow for double counting. We can say that we subscribe to the Journal of Gender and Development to support the work of scholars in Gender Studies, Political Science, and Economics. (Just don't aggregate it all together.)
Interdisciplinarity, multidisciplinarity, electronic resources, and outdated but in-use classification systems all make collection assessment a tremendously more complex and difficult task. There is a great need to cast a wider net to measure Library support for contemporary fields of study. The act of mapping collections to academic departments is the best first step to making this endeavor possible.
When library resources are matched to academic departments, you can:
There is not always—if there ever was—a straight line between the interests of academic departments and a range of Dewey or LC classification numbers. This is true even in the case of traditional fields; some English departments now emphasize film as well as written literature. For less traditional fields, the move from academic interest to library classification system is even more difficult; the needs and interests of Cognitive Sciences cannot be captured within a single classification range. Hence, if you want to assess your collection via call numbers, it may be desirable to re-map classifications to match the needs of departments rather than rely on the broad ranges set out by LC and Dewey.
All endeavors to map call numbers to collections must be local, reflecting the local interests of the academic departments involved. The mapping projects below will not fit every library. On the other hand, why reinvent the wheel? These sources can assist you in getting a good start on identifying call numbers for specific collections. Depending on the situation at your library, you might also have an interest in mapping Dewey to LC or vice versa; these resources can assist you in that work, too.