The prize went to the people who kept the thing running
The 2026 Rousseeuw Prize for Statistics has gone to five people for building and maintaining R: Brian Ripley, Martin Maechler, Kurt Hornik, Peter Dalgaard, and Luke Tierney. Prizes in statistics usually reward a theorem. This one rewards a piece of software that several million people rely on and almost nobody thinks about — a much harder thing to get recognised.
Professor Ripley’s share of that work is understood to be enormous — he is reckoned to have personally written the large majority of base R’s codebase over the decades. Nobody has published an exact accounting, but the direction of it is not in dispute.
We got the broken builds first
I was a masters student in the R 0.7 era, and later Professor Ripley’s doctoral student, working on high-dimensional ordinal classification with an SVM-related algorithm. I arrived on windoze, having never touched Linux — in a statistics department at that time, a fair way behind the line. What I remember most is not a seminar. It is that pre-release builds of R would go onto the machines in the statistics laboratory, and we were expected to do our actual work on top of them, before anyone outside the department saw them.
There was nothing formal about it. No tracker, no test plan, no word like “QA”. A room full of students with real datasets and real deadlines is a very effective way of finding out what breaks, and he had one. We were a bug-testing team that mostly did not realise it was one.
The mailing list met a different man
That is not how the wider R world knew him. On the mailing lists he was blunt to the point of legend, terse in a way that got collected into a genre of its own — the “Ripley Facts”, affectionate in the way only a reputation people respect ever gets.
Lore also held that he answered posts at every hour, and the joke that he never slept was persistent enough that somebody went and checked. A 2009 analysis of R’s first 50,000 commits plotted the most prolific core developers by hour of day and asked outright — “Does Prof Ripley Ever Sleep?” — then answered with a distribution smeared across the clock where his colleagues’ were not. Timestamps record when work landed, not when anyone slept. But it is the closest the joke came to evidence, and what it measures is the volume of unpaid hours going into other people’s problems.
What the prize is actually honouring
As a supervisor, Professor Ripley was patient with me well past the point where I had earned it. I was not a great student, and I had turned up knowing none of the tools everyone else already had; he was generous with insight anyway — a few well-placed sentences that reorganised a month of work. None of that came through in three-line mailing-list replies, and it did not need to. The prize honours decades of unglamorous infrastructure work, done out of sight, that a great deal of statistics now quietly runs on.