WorldCat is a wonderful resource, and I don’t know where we’d be without it in interlibrary loan. Most of the member libraries at the Mass Library System rely on it to search for resources of all kinds, so they can fill in as many fields as possible in their Clio requests.
But we’ve noticed that sometimes confusion arises about the results our members see in WorldCat: often the OCLC number we’re given refers to a record that has little or no holdings, or refers to libraries outside the United States (we can borrow from abroad, by the by, but it involves complicated things like IFLA vouchers, and usually costs well over $40).
One of my coworkers has come up with a good example that illustrates one of the key difficulties in refining WorldCat results to retrieve only what you want. Say you want to see which libraries own only the Stephen Fry editions of the audiobooks of the Harry Potter books (an oft-requested item). You can click on Advanced Search in WorldCat, and fill in the field for title, author, and format. But even after using the facets to the left, and paring results down even more precisely by format (Harry Potter on CD, not audiocassette), WorldCat blithely tells you that hundreds, perhaps thousands, of libraries own this item. “Great!” you think. But wait… They’re actually giving you all the libraries that own all editions of that title. To take your search just one step farther, click on the tiny blue link on the right-hand side that reads “just this edition.” Sadly, usually only libraries in Europe own these particular versions of the beloved series on audiobook.
This is an extreme example – not many libraries in the U.S. have purchased the Stephen Fry audiobooks of Harry Potter – but it is a good idea to refine searches as much as possible, and dig deeper to find exactly what you need. And we appreciate it, too!