The space problem started long ago.

At ICML last year and the year before the amount of capacity that needed to fit everyone on any single day was about 1500. My advice was to expect 2000 and have capacity for 2500 because “New York” and “Machine Learning”. Was history right? Or New York and buzz?

I was not involved in the venue negotiations, but my understanding is that they were difficult, with liabilities over $1M for IMLS the nonprofit which oversees ICML year to year. The result was a conference plan with a maximum capacity of 1800 for the main conference, a bit less for workshops, and perhaps 1000 for tutorials.

Then the NIPS registration numbers came in: 3900 last winter. It’s important to understand here that a registration is not a person since not everyone registers for the entire event. Nevertheless, NIPS was very large with perhaps 3K people attending at any one time. Historically, NIPS is the conference most similar to ICML with a history of NIPS being a bit larger. Most people I know treat these conferences as indistinguishable other than timing: ICML in the summer and NIPS in the winter.

Given this, I had to revise my estimate up: We should really have capacity for 3000, not 2500. It also convinced everyone that we needed to negotiate for more space with the Marriott. This again took quite awhile with the result being a modest increase in capacity for the conference (to 2100) and the workshops, but nothing for the tutorials.

The situation with tutorials looked terrible while the situation with workshops looked poor. Acquiring more space at the Marriott looked near impossible. Tutorials require a large room, so we looked into the Kimmel Center at NYU acquiring a large room and increasing capacity to 1450 for the tutorials. We also looked into additional rooms for workshops finding one at Columbia and another at the Microsoft Technology Center which has a large public use room 2 blocks from the Marriott. Other leads did not pan out.

This allowed us to cover capacity through early registration (May 7th). Based on typical early vs. late registration distributions I was expecting registrations might need to close a bit early similar to what happened with KDD in 2014.

Then things blew up. Tutorial registration reached capacity the week of May 23rd, and then all registration stopped May 28th, 3 weeks before the conference. Aside from simply failing to meet demand this also creates lots of problems. What do you do with authors? And when I looked into things in detail for workshops I realized we were badly oversubscribed for some workshops. It’s always difficult to guess which distribution of room sizes is needed to support the spectrum of workshop interests in advance so there were serious problems. What could we do?

The first step was tutorial and main conference registration which reopened last Tuesday using some format changes which allowed us to increase capacity further. We will use simulcast to extra rooms to support larger audiences for tutorials and plenary talks allowing us to up the limit for tutorials to 1590 and for the main conference to 2400. We’ve also shifted the poster session to run in parallel with main tracks rather than in the evening. Now, every paper will have 3-4 designated hours during the day (ending at 7pm) for authors to talk to people individually. As a side benefit, this will also avoid the competition between posters and company-sponsored parties which have become common. We’ll see how this works as a format, but it was unavoidable here: even without increasing registration the existing evening poster session plan was a space disaster.

The workshop situation was much more difficult. I walked all over the nearby area on Wednesday, finding various spaces and getting quotes. I also realized that the largest room at the Crown Plaza could help with our tutorials: it was both bigger and much closer than NYU. On Thursday, we got contract offers from the promising venues and debated into the evening. On Friday morning at 6am the Marriott suddenly gave us a bunch of additional space for the workshops. Looking through things, it was enough to shift us from ‘oversubscribed’ to ‘crowded’ with little capacity to register more given natural interests. We developed a new plan on the fly, changed contracts, negotiated prices down, and signed Friday afternoon.

The local chairs (Marek Petrik and Peder Olsen) and Mary Ellen were working hard with me through this process. Disruptive venue changes 3 weeks before the conference are obviously not the recommended way of doing things:-) And yet it seems to be working out now, much better than I expected last weekend. Here’s the situation:

Tutorials ~1600 registered with capacity for 1850. I expect this to run out of capacity, but it will take a little while. I don’t see a good way to increase capacity further. The main conference has ~2200 registered with capacity for 2400. Maybe this can be increased a little bit, but it is quite possible the main conference will run out of capacity as well. If it does, only authors will be allowed to register. Workshops ~1900 registered with capacity for 3000. Only the Deep Learning workshop requires a simulcast. It seems very unlikely that we’ll run out of capacity so this should be the least crowded part of the conference. We even have some left-over little rooms (capacity for 125 or less) that are looking for a creative use if you have one.

In this particular case, “New York” was both part of the problem and much of the solution. Where else can you walk around and find large rooms on short notice within 3 short blocks? That won’t generally be true in the future, so we need to think carefully about how to estimate attendance.