Author Archive

Do government agencies know enough about the limits of anonymization?

Monday, January 18th, 2010 by Don McIntosh

There is a new wave of open government data scheduled to crash over the US on January 22 resulting from the government’s Open Government Directive. Is the government paying enough attention to data privacy issues that this deluge could trigger, and how aware are agencies of the well-established fact that anonymizing data is often an inadequate means of protecting privacy in public sector information, and that in many cases more “scrubbing” of the data is needed before any part of it can be safely released for public use?

Until recently, many government agencies have not been motivated to provide data transparency. Compared with the work that directly aligns with their mission and funding being a visionary supporter of the principles of transparent government is not really high on the agenda. In fact, in many cases, the message from up high hasn’t really reached them at all (one senior US government official’s take on Gov 2.0 was “oh, that’s a subset of Web 2.0 isn’t it?”). If you add to this reluctance the quite significant disincentives such as the risks of being too transparent, inadvertent privacy breaches, and plain and simple costs, then it’s not surprising that the average department hasn’t been as enthusiastic as the Gov 2.0 activist community might like them to be. And if the ROI on the whole deal is often external, why bother?

Well, there’s nothing like a directive straight from the top to get things moving. As of December 8, U.S. federal agencies had 45 days to get three “high-value datasets” published online and available through data.gov. Wow! Having worked with national statistics agencies for many years, I have some grasp of how long they typically take to publish data and it’s often longer than this, especially when you are dealing with data that has not previously been published. Of course, the data in some cases might be basic lists of non-sensitive material, in which case perhaps it is not too much extra work to make it suitable for public access. What I’m interested in examining is what it will take for agencies that don’t have it that easy, who will need to derive statistics from their data, or reduce it in some way to make it “safe” for public consumption.

Firstly, why bother publishing statistics if the raw data is available? Isn’t the open data community interested in getting “raw data now”, so that it’s quick for the agency and promises maximum flexibility for users? The reality in many cases — and one that seems to still be ignored by some who work in Information Management — is that even after you “de-identify” data by stripping obviously identifying attributes from it such as names, addresses, SSNs, etc, it does not necessarily protect privacy. It can still be a fairly trivial exercise for an ill-meaning data analyst, or even a non-technical person in many cases, to re-identify many of the people in the list. That is why in many cases we’ll see statistics being released about the data, rather than the raw data itself.

Associate Professor of Law Paul Ohm from the University of Colorado released a paper about the “Surprising Failure of Anonymization” last year, citing some prominent cases where anonymized data was re-identified and pointing out that there are many laws and regulations that are based on the false assumption of anonymization being a panacea for data privacy protection. In one example he describes, a researcher demonstrated how 87.1% of people in the U.S. were uniquely identified by their combined ZIP code, birth date, and sex. He also covers the AOL search data scandal, where individuals were identified from vast volumes of data by their unique search habits, uncovering some embarrassing personal information along the way.

While the individual agencies may not all have a clear understanding of all the potential privacy issues related to open data, at least the federal administration does have a focus on this. The directive itself states that data can only be made available “subject to valid privacy, confidentiality ….. restrictions”. In addition, the “Concept of Operations” paper for data.gov does have privacy in its sights, stating that there will be working groups looking into privacy issues arising from how data is mashed up and/or used in applications. I would point out that these groups could make an early head start simply by reading Paul Ohm’s paper, and not wait until after this round of data has been released. It seems that for the moment at least, the idea of what constitutes adequate privacy protection for open data is really up to each agency to decide.

While the working groups deliberate how privacy issues that result from data mashups and the like should be addressed, many datasets will be posted to data.gov and despite the proven limits of the effectiveness of anonymization, the experience that my colleagues and I have gained from talking with people who work in Information Management in government is that key staff in at least some agencies are not sufficiently aware of this, and that in their view, anonymization is essentially all you need to do to make data safe for release. I’d be interested to know if this agrees with others’ observations.

My observation regarding government’s understanding of data privacy issues is based largely on anecdotal evidence collected by myself and my colleagues. Perhaps I am overstating things and agencies do have the required skills and knowledge to release data safely. It would be good to hear about how different agencies are dealing with the Open Data Directive and what you think about the challenges of releasing useful data without unduly compromising privacy.

Note: Ohm’s paper is fairly lengthy. For a very interesting summary of the paper, you can check out this post on ars technica, which sparked a lot of debate regarding the importance of privacy.

Gov 2.0 for Koalas - Community vs. Government Data

Thursday, December 3rd, 2009 by Don McIntosh

koala3

I heard a debate on the radio on Tuesday about whether koalas should be classified as an endangered species. There’s an article from ABC news from last month that covers the issue quite well. Oddly enough, I was reminded of it when I had a chat with Gartner analyst Andrea Di Maio that same evening when he pointed out what he called the asymmetry of Gov 2.0. What he was referring to was the fact that many communities have data of their own, and that the standards that we are demanding of government are in no way being reciprocated in terms of what is expected of communities. A question for us and for our customers (typically government agencies) is what should government do with data owned and collected by the community?

How many koalas are there? Are they a threatened species, or endangered? What do we need to do to make sure that Australia retains a diverse, healthy population of koalas? This is a hotly debated topic, with the government accused of siding with property developers at the expense of many hectares of koala habitat. As much as I’m worried about predictions of extinction of koalas within 30 yrs, I’m not trying to push either side of the argument in this post. I’ll leave that to those who are better informed about this. What I do want to do is explore what should be done with “unofficial” statistics.

So here’s the problem: we have official statistics produced by government derived from data that is objectively collected, categorized and disseminated in keeping with scientific survey practices. And then on the flip side, we have passionate communities conducting their own research which increasingly seems to involve collecting data and producing statistics. In terms of quality, I imagine that the output varies a lot. But it is data, and potentially useful data. How should government deal with that, especially where they plan or need to have data that clearly overlaps with what already exists? Could government help turn them into official statistics? I would suspect that in many cases the answer would be a rather emphatic no. However, perhaps there would be cases where there may be some benefit to government to be gained from acknowledging and making some use of community-sourced data.

At the front end of the statistical business process model published by the UNECE, there is a planning phase where existing data sources are considered for inclusion in official collections. Here’s what the UNECE says in step 1.5:

Check Data Availability: This sub-process checks whether current data sources could meet user requirements, and the conditions under which they would be available, including any restrictions on their use. An assessment of possible alternatives would normally include research into potential administrative data sources and their methodologies, to determine whether they would be suitable for use for statistical purposes. When existing sources have been assessed, a strategy for filling any remaining gaps in the data requirement is prepared…”

I’d take away from that that the authors had absolutely no thought in their minds about community data. So, if I was a community activist, I’d say that means that there is room for it to happen. After all, it doesn’t explicitly preclude a statistician from asking around to see if anyone else is out there counting our cuddly little Aussie icons. Perhaps there would be valid cases where government could collaborate in some way so that either the quality of the output is improved, or at the very least it can be better understood and therefore used appropriately.

There are a couple of issues that spring to mind…

  • Biased and/or poor quality evidence. Communities are typically passionate and biased to a particular point of view. With no standards or checks in place to determine data quality, the government would be right to be highly skeptical of any “facts” presented. The CEO of the Australian Koala Foundation (AKF) noted that over 20 years, 2000 field sites have been looked at and over 80,000 trees. Is that enough? For what? Should the government do more? Well, at the very least, they should do some due diligence, or even better, demand a bit of transparency of the AKF, which I suspect they would be quite willing to provide. It’s right that we demand transparency of the government, but it is equally right that community groups offering evidence to support their claims should be held to a similar standard. Maybe government departments need to band together to demand Community 2.0 ?
  • Inappropriate use of anecdotal evidence. Let’s face it, right now there are no doubt many policies that are based on little more than personal opinions of government executives rather than any solid evidence. People regularly draw conclusions based on direct experiences, or from stories of those they trust. Here’s a simple case in point from a comment on the ABC’s article: “Last year in the Otways I saw koalas where I had never seen them before. Seems to me that their numbers are increasing and a good thing too.” Let’s hope that’s not from environment minister Peter Garrett. This is a great evolutionary attribute that allows us to form opinions on things that might actually affect us but it doesn’t serve us well when we choose to use it to form a model of complex, widespread populations with many different local influences at play. I hardly need to point out what a huge role data can play when it comes to making informed decisions.
  • Real experts in the public ready to make a contribution. There are many informed and passionate members both within the official communities, as well as in the public at large. What if we could give them a little bit more in the way of facts and figures to work with? As it is, there is a fair bit of scientific knowledge introduced by commenters. One knowledgeable commenter had a fascinating insight into the problem: “Koala populations are notoriously difficult to monitor. They are such a specialized animal that a minor change in habitat can lead to local extinctions in one area while they pop up somewhere else where they haven’t been seen in living memory.” Well, it sounds like he knows about it. It would be helpful if there was a way for him to easily reference credible evidence to back that up.

As one commenter noted: “At least it’s a positive step to have some dialogue over koala population density, and clearly there are big differences in estimates.” Yep, that pretty much sums it up. The question is, how do we get to the next step? Personally, I don’t know. I think that Andrea got it right when he said that government should acknowledge the existence of the community data sources. What they do next is an open question. Having surveys with tens of thousands of data points may still be unreliable depending on the use, but it may be better than making conclusions based on what Fred saw on his weekend trip to the Otways. I’d love to hear what other community vs government data debates people have had, and what the outcome was.

Australian Privacy Awards 2009 - “Hey, that’s just what we do!!”

Friday, November 13th, 2009 by Don McIntosh

Most people have an opinion about privacy these days, from Scott McNealy’s memorable throw away line “You have zero privacy. Get over it”, to the fierce concerns many people have around how much information Google stores about each and every one of us. Well, I certainly feel it’s important and it was great to have the opportunity to meet many other like-minded people at the Australian Privacy Awards dinner last night.

Special Minister of State and Cabinet Secretary Senator Joe Ludwig started the night with a good overview of the state of play, with many people and organisations struggling to come to terms with technology advances such as social networking that have such far-reaching effects on privacy. He mentioned the need for balancing government transparency and protecting personal information so many times that I felt like jumping up and saying “Hey, that’s just what we do!!

It certainly was an honour to receive the “highly commended” award in our category on Space-Time Research’s behalf and I’d like to thank the Office for the Privacy Commissioner for giving us the opportunity to be part of the whole event, and to meet and talk with so many people who work in this area. However, what I really wanted to mention in this post was a couple of award winners that I found particularly interesting.

Dr Roger Clarke was a worthy winner of the Australian Privacy Medal. Dr Clarke used his speech to remind the audience that there was a lot of real work that needed to be done, and that that he felt his medal was a little tarnished, because some people including some of the award winners were essentially just window dressing (not his terms - but I think that was the gist of it), and not really applying a genuine effort to promote privacy. Rooms are typically politely quiet when people give speeches but I think in this case it was a pregnant, slightly awkward kind of quiet.

There’s some great information on Dr Roger Clarke’s website about information privacy. In fact, I came across one note where he mentioned data protection that has made me rethink why we are using this term. He makes a really good point that many laws focus on data protection, where the focus is protecting data about people. As he explains, the real issue is to protect the people and you do that by considering what information might be derived from the data, rather than just protecting the data itself. Very good point.

Another winner I really liked was the Victorian Department of Justice (and not just because they are our customer). Who would have thought promoting privacy practices could be so fun or entertaining? Well, the people at Department of Justice certainly do. As an example, their most recent idea is to put together a radio show based on the X-Files concept. It will be called the P-files, with some really witty variations on Scully and Mulder’s names that have totally slipped my mind. One way or another, they plan to slip in the line “is that a USB stick in your pocket or are you just pleased to see me?” It was really refreshing to hear about their work and I do hope they have inspired many people there to take an equally innovative and enthusiastic response not just to promoting privacy practices, but to many other aspects of their work. I’m sure that even Dr Clarke would agree that they were really deserving winners.

Until 18 mths ago, I’d never heard of the office of the Privacy Commissioner. Now I know a whole community of people who are working to help Australians find the right balance and have some control of what parts of their lives are public knowledge. Privacy may not seem like an important issue to many in this age of Facebook and with the attitudes of Gen Y but I think Roger summed it up very nicely in his speech: “Privacy doesn’t matter until it does.”

Australian Privacy Awards 2009

Protecting confidentiality - some real life examples

Sunday, November 1st, 2009 by Don McIntosh

This post blog is on how we are enabling our customers to disseminate detailed information while protecting the privacy of individuals. In the context of being providers of Official statistics, making data more available, and making governments more transparent, we show that it *can* be done - you *can* release data.

We are currently engaging with three customers and developing new requirements around the area of privacy protection on their data. For two of the three, the main goal is to deliver more detailed, useful data to their customers without compromising privacy concerns. The other key goals are around reducing the risk of accidentally releasing sensitive data (a goal of increasing importance given the Gov 2.0 fueled demand for more open data), and reducing costs associated with the application of privacy protection. I thought I’d write a short note to summarise our work in this area of late.

We have an API plugin architecture for applying disclosure control. Basically, you can build your own modules that do things like adjust, conceal, and/or annotate cell values based on certain rules, or reject a query if it’s deemed too sensitive for whatever reason. You can also record query details and use them to monitor for potential privacy intrusions.

The work we are looking at doing in relation to current customer requests includes the following:

  • Implementing plugins with customised rounding and concealment rules. This is straight forward work as far as our current architecture is concerned, and helps our customers with these requirements to implement rules that maximise the data they can make available. For one customer, we have written a plugin that will suppress numbers less than a certain value, and any related totals. So for example, if you were suppressing all numbers in a table less than or equal to 3, a simple table would show suppression of that cell, plus any totals containing that cell. The example table demonstrates how a returned table would look. By suppressing the totals, you are preventing someone from back-calculating a value that has been suppressed.
Suppressed Table

Suppressed Table

  • Allowing custom selection of different rule combinations for testing and more advanced use of disclosure control. This is useful especially where you have a few in-house specialists who are authorised to be more lenient in terms of what rules need to be applied when responding to ad hoc information requests.
  • Extending confidentiality to apply to the output of calculations (SuperSTAR field derivations). For example, you might have a function that in some cases returns “..C” instead of a real value for certain cells as per the example above. Confidentiality can be extended to work with derived data. For example, it would be useful for determining a statistical mean or median and concealing the result if there was less than a certain number of contributors.

We are really keen to hear from our customers and other interested parties. If you have some recent experience in using confidentiality in SuperSTAR or elsewhere, or would like to give us any kind of related feedback, please do feel free to leave a comment or contact us directly.