Showing posts with label privacy. Show all posts
Showing posts with label privacy. Show all posts

Wednesday, October 7, 2009

Google ambitions ignore digital ephemera of yesteryear

Wired recently had an article critiquing Googles ambitious reach into digital curation of books with a reminder of the last large digital library it undertook and all but abandoned. Usenet.

First Google rescued post-1995 Usenet (a dial-up message board system founded in 1980) from Dejanews in 2001. Google later was able to add millions of posts to this from the magtape of an old Unix guru, Marc Spencer. This gave Google a digital library from over 2 decades of 700 million articles from 35,000 newsgroups.

Wired interviews the Unix guru whose archive supplies a bulk of Google groups (and can't seem to get his name right - is it Marc or Henry Spencer?). Speaking on behalf of his community of Usenet users, Mr. Spencer is very disappointed with the poor searchibility of the material he provided Google.

I would ask: Where are the finding aids? How are things catalogued? Does Google use any of the methods that have worked for traditional archives spanning hundreds of years? No, Google can't even retrieve the legendary alt.gothic flamewars of 1993.

Well, perhaps the world is a better place for that.

But in all seriousness, if anything required professional curation, Usenet could be that. Many from my generation compiled subject knowledge in the early 90s in the form of F.A.Qs, discographies, videographies, and many other encyclopediac collections of unpublished popular (or not very popular) material. Did we save it all? Probably not. There were news-groups for great swaths of information that probably did not carry over to the world wide web post 1995, or even post 2001.

Granted, an enormous amount of Usenet one would not want to have see the light of day, for reasons legal and sundry that could make Craigslist pale in comparison. Still, there are volumes of music, film, and sub-cultural anthropology I have in my file cabinets printed on dot-matrix printers in 1992 that I have yet to see mirrored online or in zines, magazines or books. As I get older and de-clutter, and deem certain material unnecessary or not keeping in with my current interests or values, that information will most likely be lost.

I think a great idea would be for there to be a way to feed and properly code Usenet material (i.e. Usenet group "such and such" date: 1996) and feed the archive anonymously into Wikipedia.

I think the anonymous Wiki framework would be the best platform to mine and add Usenet knowledge and curate it in a central way that would be searchable. Usenet entries would be date-logged as historical data, and contestation, edits and updates would need to follow the historical Usenet information. This would give Wiki a valuable historical layer that I currently find missing. There are times when Wiki feels to me like urban Las Vegas, where the old is torn down and forgotten to make room for the new. What is Wiki kept historical layers to their entries? I think it would be interesting to see a Wiki article from 7 years ago on a given topic.

Wednesday, September 16, 2009

Data Anonymization

Ohm, P. (2009). Broken promises of privacy: Responding to the surprising failure of anonymization. SSRN.


In this article the author investigates the merits of anonymization. Anonymization is a now-standard practice where datasets are stripped of personally identifiable information (PII) such that they are agreed to be suitable for sharing, whether with a private party or the public. Ohm argues that anonymization is inadequate in the face of reidentification, a strategy where datasets are combined with external data and information to yield unique data fingerprints of individuals.


The author highlights key advantages to anonymization in a social, political, and legal framework. It allows a discrete action to take place before data can be shared. It allows this action to be enforced and legislated, and so consequently allows an easy division between responsible data-sharers and irresponsible parties. Anonymization balances interests between researchers, legislators, and the public.


Key to anonymization is the idea of PII. When PII are identified in a record (perhaps a name, ZIP, birth date, etc.), those values are either suppressed (removed) or generalized (for instance a full birth date is translated to just the year of birth) so that they are no longer deemed personally identifiable values.


Ohm presents several instances where datasets anonymized in this fashion were used to very accurately identify a single person or demonstrate the ease of this task: the 2006 AOL release of 20 million search queries that identified user 4417749 as Thelma Arnold, the release of Massachusetts state employee health records by the Group Insurance Commission that revealed the governor’s own health records (diagnoses and prescriptions included), and Netflix’s release of 100 million movie ratings records in an open contest to develop a better recommendation algorithm. In the latter case UT researchers were able to demonstrate how little outside data an investigator needed to identify individual’s profiles amongst these records.


The author goes on to suggest that “anonymization” and PII are not realistic terms. The former implies absolute success without varying degrees, and the latter fails to account for the accretion of non-PII fields to constitute a unique identity, which is the primary strategy of reidentification. The author also demonstrates how attempts to extend PII fields invariably decrease the value of data: the more anonymous data becomes, the more value it loses with researchers.


On this struggle the author contrasts the US’s approach to privacy-data legislation and the EU’s. The US largely functions sector-by-sector, addressing the health profession, scientific communities, state departments, etc., in turn. EU maintains a Data Protection Directive which seeks to regulate all data everywhere for PII elements. Both have serious drawbacks, since US legislation is liable to skip or under-regulate whole industries with the idea that its data cannot be used harmfully. The EU meanwhile faces a rising tide of reidentification instances that place more data in the PII camp, thus severely limiting sharing.


Last is a consideration of alternatives to legislating privacy in datasets. The author argues that comprehensive and sector-by-sector approaches need to be combined, and that a risk-assessment of data can guide the sector-by-sector guidelines. Some of the risk factors the author lists are: data handling techniques, whether data is moving to a private or public party, the sheer quantity of the data (since reidentification benefits considerably from large datasets), and motive (academic researchers have little motive to reidentify because of rules and professionalism).


We’ve mentioned privacy briefly in class, by I think this review of anonymization is relevant to digital curation since the field hinges on the idea of mass sharing of data that’s not necessarily tracked carefully. Fortunately the field consists of academic researchers and graduate students so it seems unlikely that in private-to-private data transactions much malevolent intent will occur. Anonymization will probably be used quite a bit in curation since it allows one to “share and forget.” So long as that’s the case it’s good to acknowledge that anonymized data has only been scrubbed to a certain degree, and in conjunction with other external datasets could achieve a lot more specificity than originally intended.