Over on Next Generation Catalogs for Libraries, NCSU's Emily Lynema, asked me:So I decided to see how hard it would be to write a script to compare the LibraryThing dataset against a simple export from our library system. It turns out it didn't take to long. And I have posted the perl source code on my personal website so you no longer have that as an excuse for not helping Tim out."Do you have any idea of the coverage of non-fiction, research materials in LT? Have you done any projects to look at overlap with a research institution (or with WorldCat)?"No, we haven't. And I'm dying to find out, both for academic and non-academic libraries.
Here are the stats for The University of Waikato Library:
Out of approximately 500,000 Bib records in our database I found only about 178,460 unique ISBNs. LibraryThing has 1,774,322 ISBNs so they have ten times as many as us! Note: This was found to be an error during normalisation. The number is now 292,073
UoW Library and LibraryThing have
|Database||Total ISBNs||Unique ISBNs||Percentage Unique|
|University of Waikato||292,073||218,696||74.88%|
Total ISBNs in common: 73,377
I figure since they asked the question, NCSU Libraries should be next...
Update: Updated Figures after discovering I had dropped a whole bunch of ISBN's when normalising them.