Mathematically modelling the Labour leadership nomination race

No politics here – just some maths.

But if we use a Zipf distribution (see here for more about that) we get a pretty good fit for the three front runners – Keir Starmer, who currently has 43 nominations from constituency labour parties, Rebecca Long-Bailey who has 17 and Lisa Nandy who has 10 – if we use a coefficient of 1.35 over their rank.

All three of these are on the ballot anyway because of trade union and other support, so the question is whether fourth placed candidate Emily Thornberry, currently with just three nominations, can make it.

The bad news for her is that this (admittedly simple) model suggests not. Indeed she is already seriously under-performing based on her rank. If the coefficient is correct she ought to be on 7 or 8 nominations – but right now she is performing as if she was in seventh place.

If her performance remains at this level it’s essentially mathematically impossible for her to make the ballot threshold of 33 nominations.

So – a prediction: if (around) 400 CLPs nominate then the model points to 236 for Starmer, 92 for Rebecca Long-Bailey, 53 for Lisa Nandy and 17 for Emily Thornberry.

Update: People better informed than me suggest 400 is a low figure for the number of nominating constituencies and for 500 the figures are: Keir Starmer 295, Rebecca Long-Bailey 116, Lisa Nandy 67 and Emily Thornberry 21. For Thornberry to make the field (on current performance remember) there would have to be 750 nominations – which is about 100 more than the mathematically possible maximum. So either Thornberry’s performance will have to significantly improve or she is out.


One response to “Mathematically modelling the Labour leadership nomination race”

  1. […] Zipf model I outlined here looks to be reasonably robust – though maybe the coefficient needs to drop to somewhere […]

%d bloggers like this: