Saturday, July 25, 2009

Sensys 2009 PC meeting

The Sensys'09 PC meeting was held here at Harvard a couple of Saturdays ago. I meant to post about this earlier, but a little something got in the way.

This year we had 119 full paper submissions (down a bit from last year) and accepted 21 papers, for an acceptance ratio of 17.6%. This is similar to the acceptance ratio for previous years, and I think it represents a healthy level of competition for the conference. Personally, I would have preferred that we accepted closer to 25 papers, but at some point there's only so much pressure one can put on the program committee to make that happen. The full list of accepted papers is here. It is a very strong program and Jie and I are both extremely appreciative of the program committee for all of their hard work.

Overall, I was very happy with the reviewing process this year. The model we used for Sensys was similar to other top-flight systems conferences: PC members do the reviewing themselves (rather than farming out to external people or students); they write detailed reviews; and everyone has to attend the PC meeting in person. The program committee did a fantastic job and worked very hard to make this happen. On average each PC member reviewed 22 papers. We reviewed papers in two rounds. All papers were assigned three reviews in the first round. Roughly 50% of the papers were considered in the second round and got at least two additional reviews, sometimes more.

During the PC meeting, we grouped papers roughly by topical area, rather than simply ordering them globally by score. This made it possible to directly compare multiple papers on, say, time synchronization during the discussion. I think this worked very well as it provided more context for the discussion on a given paper and often some of the same PC members were involved in reviewing papers in a given area. At the end of the first pass we had roughly 15 papers in the "accept" list and about the same number in the "maybe" category. We then went through a second pass on the "maybe" papers to come up with the final list. The PC was generally very positive during the discussion; and in a few cases a reviewer with an initially negative reaction to a paper was able to reconsider as the rest of the program materialized.

One thing I am mindful of is that it is sometimes harder to accept a paper when it has "too many" reviews. At SIGCOMM, NSDI, and other conferences, I've seen papers get 7 or more reviews in the final round. My concern is that beyond a certain point enthusiasm for a good paper tends to wither with more reviewers weighing in on it. We recognize that no paper is perfect and the question was which papers were both technically sound and interesting enough to constitute a good program. The two-round process seemed to strike the right balance. I did not feel that we were accepting or rejecting papers based on not enough information.

We also had a fairly diverse program committee this year, including some folks representing areas not traditionally associated with Sensys. Part of our goal here was to ensure that the PC was not too insular and that we got a broad range of opinions. We also wanted to broaden the scope of the conference to encompass non-conventional sensor networks. We have a few good papers involving application case studies as well.

It should be an exciting conference - hope to see you in Berkeley in November!


  1. Matt, I notice you are an author on a paper. What is your thinking on a PC chair having a paper in their own conference? How did you handle conflict of interest?

  2. That's right, I do have a paper in the conference. So does Jie Liu, my co-chair.

    We had a long discussion with others, including the SenSys Steering Committee and organizers of other conferences, before deciding to allow Program Chairs to submit to the conference. SenSys, along with many other conferences, has traditionally allowed Program Chairs to submit papers. We felt that it would be unfair to our students and collaborators to suddenly change this practice for this year. If you look back on past SenSys conferences, the program chairs are often fairly active members of the community and it is not unusual for them to publish papers in the conference when they are chairing it.

    It is always a tricky issue as it is important to avoid any kind of conflict of interest. In this case, the Program Chair papers were handled completely outside of the regular reviewing system and as a result Jie and I never had any knowledge of or influence over the identity of the reviewers. The reviewers were no doubt aware that these were PC authored papers and we hope they held these papers to a very high standard. Jie and I both left the room during the discussion of these papers and delegated the "chair" role to another PC member.

    I'm happy to answer any questions about the process as we think it's important to be as transparent as possible!


Startup Life: Three Months In

I've posted a story to Medium on what it's been like to work at a startup, after years at Google. Check it out here.