IMA Conference 2024
January 12, 2024
Just on the way back from the 9th World Congress of the International Microsimulation Association in Vienna. Northumbria allowed Howard Reed and me to go to present our NIHR work.
It was fun. Met some good people, heard some interesting papers, and our presentations went fine, I think.
I did two. First was a 1 1/2 hour pre-conference hands on thing introducing microsimulation in Julia, then Howard and I presented the NIHR work.
Live Coding A Tax Benefit Model.
I volunteered for this! I’d imagined 4 or 5 people but the room was packed out. I’m just really lucky to be surrounded by the best people. Judith ran through the whole thing the day before, made some really useful notes - the upshot was I was planning on taking them through far too much stuff and should cut down drastically. On the day J and H stopped me panicking on the day about screens, networks and all the things I always panic over, and H kept an eye on things during the presentation and stopped me making some silly mistakes like not saving files. And my son sneaked it - he’s doing is International Law masters at the University.
The material is on Github. Some thoughts:
- Pluto works really well in this context;
- A rehearsal really helps, even it you’re not planning on sticking to a script;
- I used that repository to encourage people to pre-load the right Julia version and some packages before the event, but not everyone saw it;
- you can hide if not actually prevent the time to first plot (TTFP) thing by loading packages incrementally: so just Pluto in the REPL, start that, then just enough to get some data, talk a bit, then plots and whaterver else. TTFP means essentially that Julia buys its very fast runtimes at the expense of slow startup times, and you don’t want to have to wait 10 minutes in a live class while packages compile if you can avoid it;
- I had a real worry with the data because the conditions the Archive put even on publicly available teaching datasets are pretty hard to comply with in a setting where I couldn’t know who was turning up. Fortunately I’d been experimenting with SynthPop and SimPop, two R packages for generating synthetic datasets that resemble some true target dataset. Of the two, SynthPop is much the easiest to use though SimPop has useful features like being able to mimic household structures over multiple records. So I took an old UKDS teaching LCF subset, aggregated some of the records, ran it through SynthPop and we were good to go. I’m not 100% sure what SynthPop is doing, but the marginal distrubutions are remarkably close to the base data. The R code is in the repo and the synthetic dataset is here;
- the Blue Peter approach of building something and getting everyone to play along works well: better than explaining some long list of language features I think;
- people had problems with getting Wifi, with having old Julia versions installed and other stuff but it was lovely to see people helping each other out. It was J who reminded me to build in slack for all this.
In src there’s the more complicated model I’d planned to use and also the drastically stripped down one I ended up live-coding and walking people through. There’s a lesson there.
I think people enjoyed it - going slow through a very simple example meant that most people got the model we were building to work, and that’s a pretty satisfying feeling for everyone, I hope.
TriplePC/NIHR
On the Tuesday we had our TriplePC presentation. Howard did most of it and I ren though a live model demo. Howard is a very good presenter, the model didn’t fall over, and I can wave my arms around, so all in all it went OK. Here’s the presentation. There were 4 presentations in 1 1/2 hours including questions, so it’s all pretty compressed. The more presentations I do, the more I want to cut things out and simplify; just get a few messages across.
The rest of the conference
The conference was really well organised: very Austrian. Martin Spielauer, the main organiser, was very accomodating & friendly and the University tech staff were great for us - not always a given.
I liked a lot of the papers I went to. I’ve always wanted to get into Agent Based Modelling so I went to a session on that. Interesting, but pretty uncompromising presentations with pages of small-multiple graphs, lots of maths, hard to read text. Slow down! The papers in our session were well presented but sometimes it was hard to see what they were trying to achieve. I went to some straight tax-benefit papers and some labour supply/dynamics things. A recurring theme is that things get a bit off whenever Euromod is involved - remarkable organisation/Grant extraction system, but well dodgy software, super-overconfident researchers. The paper that impressed me most was a relatively straighforward one on projecting family care in Germany. I think my students would like that one.
The Policy Engine people went all in and staged their own fringe event, with pizza and wine, in a rental office down by Prater. Lots to think about there and worth a post of its own.
Downside was I came down with some horrible non-covid thing which had everything: nosebleeds, hacking cough, diarrhea.. Adrenaline gets you through doing the presentations but I’m pretty exhausted now & I bunked off straight after our 2nd presentation so missed a lot of socialising and the whole of the final day.
So that’s Vienna for a while. I love that place.