Friday, August 6, 2010

How Many Licks Does It...I Mean....

There are so many books out there in the world that they're more of less countless. Or so one would think.

Google, however, would not settle for such a generalization and has taken matters into their own hands, determined to figure out just how many books actually exist.

Yesterday, the Huffington Post linked to Inside Google Books, where they thoroughly explained how Google calculated this factoid and their results. It's a veryinteresting post, though be forewarned, it's not exactly simplified and it is book history :-p (Hey! Dorks like me enjoy this stuff!):

When you are part of a company that is trying to digitize all the books in the world, the first question you often get is: “Just how many books are out there?”

Well, it all depends on what exactly you mean by a “book.” We’re not going to count what library scientists call “works,” those elusive "distinct intellectual or artistic creations.” It makes sense to consider all editions of “Hamlet” separately, as we would like to distinguish between -- and scan -- books containing, for example, different forewords and commentaries.

One definition of a book we find helpful inside Google when handling book metadata is a “tome,” an idealized bound volume. A tome can have millions of copies (e.g. a particular edition of “Angels and Demons” by Dan Brown) or can exist in just one or two copies (such as an obscure master’s thesis languishing in a university library). This is a convenient definition to work with, but it has drawbacks. For example, we count hardcover and paperback books produced from the same text twice, but treat several pamphlets bound together by a library as a single book.

Our definition is very close to what ISBNs (International Standard Book Numbers) are supposed to represent, so why can’t we just count those? First, ISBNs (and their SBN precursors) have been around only since the mid 1960s, and were not widely adopted until the early-to-mid seventies. They also remain a mostly western phenomenon. So most books printed earlier, and those not intended for commercial distribution or printed in other regions of the world, have never been assigned an ISBN.


What about other well-known identifiers, for example those assigned by Library of Congress (Library of Congress Control Numbers) or OCLC (WorldCat accession numbers)? Rather than identifying books, these identify records that describe bibliographic entities.


So what does Google do? We collect metadata from many providers (more than 150 and counting) that include libraries, WorldCat, national union catalogs and commercial providers. At the moment we have close to a billion unique raw records. We then further analyze these records to reduce the level of duplication within each provider, bringing us down to close to 600 million records.

Does this mean that there are 600 million unique books in the world? Hardly. There is still a lot of duplication within a single provider (e.g. libraries holding multiple distinct copies of a book) and among providers -- for example, we have 96 records from 46 providers for “Programming Perl, 3rd Edition”. Twice every week we group all those records into “tome” clusters, taking into account nearly all attributes of each record.


So after all is said and done, how many clusters does our algorithm come up with? The answer changes every time the computation is performed, as we accumulate more data and fine-tune the algorithm. The current number is around 210 million.

Is that a final number of books in the world? Not quite. We still have to exclude non-books such as microforms (8 million), audio recordings (4.5 million), videos (2 million), maps (another 2 million), t-shirts with ISBNs (about one thousand), turkey probes (1, added to a library catalog as an April Fools joke), and other items for which we receive catalog entries.

Counting only things that are printed and bound, we arrive at about 146 million. This is our best answer today. It will change as we get more data and become more adept at interpreting what we already have.

Our handling of serials is still imperfect. Serials cataloging practices vary widely across institutions. The volume descriptions are free-form and are often entered as an afterthought. For example, “volume 325, number 6”, “no. 325 sec. 6”, and “V325NO6” all describe the same bound volume. The same can be said for the vast holdings of the government documents in US libraries. At the moment we estimate that we know of 16 million bound serial and government document volumes. This number is likely to rise as our disambiguating algorithms become smarter.

After we exclude serials, we can finally count all the books in the world. There are 129,864,880 of them. At least until Sunday.

Read the entire post HERE

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