On Wed, Jul 21, 2010 at 2:36 PM, Jakob <[email protected]>wrote:
> Hi, > > Talking about identifiers for bibliographic records I just want to > stress one crucial point: > > > This gives us the following key, guaranteed to be unique: > > KangHsuKrajbich20091011b > > There is absolutely no such thing as a "guaranteed unique identifier" > that can be derived from existing metadata. You will *always* have > false positives (different publications get the same identifier [1]) > and false negatives (same publication has different identifiers [2]). > Fuzzy identifiers even occur if they are created by the publisher or > author himself (for instance duplicate ISBNs for definitely different > editions or even totally different books). If you argue about > identifiers please keep in mind that you *always* talk about > heuristics but not about something "unique per se". Existing > identifiers only differ in the ratio of false positives and false > negatives. > > The only way you may get unique identifiers is to assign your own > identifiers that are *not* derived from the content - such as > auto-incremented record ids in a database. Even then they are not > unique if you change the content because the identity of the object > may change. A MD5 or SHA-sum on the full content [3] or the version id > in a versioning database (like MediaWiki) is unique but not practical > if you want to change content. A solution to this problem is to let > people decide in every single case about how an identifier looks like > and when it should change (example: Wikipedia article titles). But > then the identifiers are not permanent (records may split and join and > be renamed). > > That's the way it is. You have to decide which problem to solve with > an identifier and then be aware of its limitations. As Brooks [3] > wrote there is no silver bullet - so there is no silver identifier. > > Cheers > Jakob > > [1] For instance if you have a common name and a general title or if > you want to distinguish the printed version and the presentation > slides of the same publication etc. > > [2] For instance different ways to abbreviate and/or write the name of > an author and/or title, different years (year of preprint vs year of > printed version) etc. > > [3] See http://en.wikipedia.org/wiki/No_Silver_Bullet which cites an > article that has been published in 1986 and 1987, and probably > reprinted in another year - so what's the identifier? ;-) > > Hi Jakob, I would like to counter this point with the following rule: There is always a way to adjudicate ambiguity. It is easy to create a rule that works in 90% of cases: Author1Author2Author3EtAl10 It is easy to modify this rule to work in 99% of cases: Author1Author2Author3EtAl20101011b Modifying the rule to work in 100% of cases requires a community of users to adjudicate the relatively small number of special cases. Brian
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