April 2012 Archives


April 9, 2012

The IETF RTCWEB WG has been operating on a fast track with an interim meeting between each IETF meeting. Since we needed to schedule a lot of meetings, thought it might be instructive to try to analyze a bunch of different locations to figure out the best strategy. Here's a lightly edited version of my post to the RTCWEB WG trying to address this issue.

Note that I'm not trying to make any claims about what the best set of venues is. It's obviously easy to figure out any statistic we want about each proposed venue, but how you map that data to "best" is a much more difficult problem. The space is full of Pareto optima, and even if we ignore the troubling philosophical question of interpersonal utility comparisons, there's some tradeoff between minimal total travel time and a "fair" distribution of travel times (or at least an even distribution).

The data below is derived by treating both people and venues as airport locations and using travel time as our primary instrument.

  1. For each responder for the current Doodle poll, assign a home airport based on their draft publication history. We're missing a few people but basically it should be pretty complete. Since these people responded before the venue is known, it's at least somewhat unbiased.
  2. Compute the shortest advertised flight between each home airport and the locations for each venue by looking at the shortest advertised Kayak flights around one of the proposed interim dates (6/10 - 6/13), ignoring price, but excluding "Hacker fares". [Thanks to Martin Thomson or helping me gather these.]

This lets us compute statistics for any venue and/or combination of venues, based on the candidate attendee list.

The three proposed venues:

  • San Francisco (SFO)
  • Boston (BOS)
  • Stockholm (ARN)

Three hubs not too distant from the proposed venues:

  • London (LHR)
  • Frankfurt (FRA)
  • New York (NYC) (treating all NYC airports as the same location)
Also, Calgary (YYC), since the other two chair locations (BOS and SFO) were already proposed as venues, and I didn't want Cullen to feel left out.

Here are the results for each of the above venues, measured in total hours of travel (i.e., round trip).

Venue         Mean         Median           SD
SFO           13.5             11         12.2
BOS           12.3             11          7.5
ARN           17.0             21         10.7
FRA           14.8             17          7.3
LHR           13.3             14          7.5
NYC           11.5             11          5.8
YYC           14.9             13         10.2
SFO/BOS/ARN   14.3             13          3.6
SFO/NYC/LHR   12.7             11.3        3.7
XXX/YYY/ZZZ is a three-way rotation of XXX, YYY, and ZZZ. Obviously, mean and median are intended to be some sort of aggregate measure of travel time. I don't have any way to measure "fairness", but SD is intended as some metric of the variation in travel time between attendees.

The raw data and software are attached. The files are:

home-airports: the list of people's home airports
durations.txt: the list of airport-airport durations
doodle.txt: the attendees list
pairings: the software to compute travel times
doodle-out.txt -- the computed travel times for each attendee

This was a quick hack, so there may be errors here, but nobody has pointed out any yet.

Obviously, it's hard to know what the optimal solution is without some model for optimality, but we can still make some observations based on this data:

  • If we're just concerned with minimizing total travel time, then we would always in New York, since it has both the shortest mean travel time and the shortest median travel time, but as I said above, this arguably isn't fair to people who live either in Europe or California, since they always have to travel.
  • Combining West Coast, East Coast, and European venues has comparable (or at least not too much worse) mean/median values than NYC with much lower SDs. So, arguably that kind of mix is more fair.
  • There's a pretty substantial difference between hub and non-hub venues. In particular, LHR has a median travel time 7 hours less than ARN, and the SFO/NYC/LHR combination has a median/mean travel time about 2 hours less than SFO/BOS/ARN (primarily accounted for by the LHR/ARN difference). [Full disclosure, I've favored Star Alliance hubs here, but you'd probably get similar results if, for instance, you used AMS instead of LHR.]
  • Obviously, your mileage may vary based on your location and feelings about what's fair, but based on this data, it looks to me like a three-way rotation between West Coast, East Coast, and European hubs offers a good compromise between minimum cost and a flat distribution of travel times.