This is the phase of the Labour leadership contest in which people try and guess at what the candidates believe via means other than what they say. In some ways, that’s understandable: the hustings format, four 40-second answers to identical questions, is dull and unenlightening. Instead, commentators look at what they’ve said in the past; how they’ve voted in the past; the company they keep and who supports them; what they look like; and the state of their hair. I’m joking, of course: most are going by the hair.

In fairness, all the other data yields confusing or, at best, inconclusive results. The most that you can tell about voting record is that Rebecca Long-Bailey was by far the most Corbyn-loyal of the candidates: yet if you put loyalty to Jeremy Corbyn as the top priority, then many criticisms of Keir Starmer – that he was temporarily against freedom of movement, for instance – melt away, since that stance was the price of frontbench loyalty. Unions have broken every way but Emily Thornberry’s (Unite for Long-Bailey; Unison and Usdaw for Starmer; GMB for Lisa Nandy) and classic evaluations of tribes within the parliamentary Labour party don’t really work for Starmer or Nandy, neither of whom fit neatly into any faction.

Jess Phillips threw a spanner in the consensus when, upon withdrawing, she threw her support behind Nandy, who thereby became de facto the candidate of the centre (history doesn’t relate how she felt about this favour). Many still hold Starmer as the natural centrist, his popularity a sign that “sensible Labour” (as Paddy Ashdown used to call it) is returning to its senses and dominance. This is mainly visual. He has none of the sartorial cues of radicalism – Michael Foot chic, if you like – therefore, if he says anything radical, then he’s taken to be strategically tilting left. This analysis offers no clue as to why he never says anything remotely centrist.

The cliches around remain are another complicating cross-current; a pro-EU stance is read as a centrist signifier. The idea that anyone could be leftwing and remain, let alone hard left and hard remain, has been completely erased from the narrative of Brexit; despite the fact that this was pretty much the entire Labour party. Anyway, add that in, and the centre-to-left spectrum goes Thornberry, Starmer, Long-Bailey, Nandy. Which of course capsizes all previous readings.

There are known unknowns, principally which way new joiners will jump, since they weren’t allowed to vote on nominations

It is worth considering, here, how the Labour members see things – partly because it’s quite different, mainly because they will be the ones voting for the leader. Starmer currently enjoys a convincing lead among constituency Labour party nominations. The deadline isn’t until Valentine’s Day; so far 231 CLPs have nominated (233 have nominated for deputy), and Starmer has a clear lead, with 138 nominations, and that seems to be accelerating: three-quarters of the local parties that declared over the weekend chose him. Long-Bailey has 58, Nandy 26, Thornberry nine. Historical loyalty to Corbyn (if we can call the past five years a history) is no definite indicator of a nomination for Long-Bailey: North Norfolk and Brent Central nominated Corbyn in both 2015 and 2016, and went for Starmer, while North Devon and Elmet and Rothwell, with the same 2015-16 pattern, chose Long-Bailey. Constituency parties simply don’t shake down in predictable ways: so there are CLPs that nominated Andy Burnham or Yvette Cooper in 2015, but Corbyn rather than Owen Smith a year later and – more strangely – those who nominated Liz Kendall in 2015, but nobody at all in 2016. Members nominate and vote on criteria much more detailed than factional allegiance.

There are some known knowns: Thornberry, if trends continue, won’t make the ballot. The only group with whom Long-Bailey has a lead over Starmer is members who voted for Corbyn in 2016 (for the superstitious, this lead is the dreaded 52:48).

And there are known unknowns, principally which way the 100,000 new joiners will jump, since they weren’t allowed to vote on nominations, but will be allowed to vote on the leader. Internal polling and general hunches suggest that they will be voting against Long-Bailey, on the basis that if you wanted a Corbyn continuity candidate, you’d need a very good reason not to have already been a member.

Nevertheless, Long-Bailey is considered very unlikely to finish third; MPs are barred from using party data, so the only phone-banking muscle at play is that of Momentum and Unite, both of which, of course, will be campaigning for her. But that’s actually better for Starmer supporters than they might suppose, since something interesting happens when Long-Bailey comes third, as she did in the Vauxhall CLP meeting last week: her second preferences overwhelmingly favoured Nandy, who duly beat Starmer to the nomination. Starmer is in a far stronger position in a runoff against Long-Bailey, since he and Nandy’s second preferences tend to go to one another. But reverse that and put Nandy in a runoff against Long-Bailey and her prospects are nothing like as strong as Starmer’s, with 74% of the 2016 Corbyn voters favouring Long-Bailey. Thornberry’s second preferences – and this data has been haphazardly rather than officially passed on to the CLP nominations Twitter account, which itself isn’t what you’d call official – are, confusingly, splitting pretty evenly between Starmer and Long-Bailey.

But if the preference system of voting is as capable of delivering shocks and surprises as it’s ever been, the real unpredictability here is that the old faultlines have been superseded. If the “centre” ever had an organised and coherent core, it was as a remnant of Blairism, which no longer carries the same force (as evinced by the unpreparedness of the candidate that centre landed on). Leave and remain constitute no clear dividing line, either. It’s become a platitude for candidates to promise an end to factionalism; but it feels like members are ending it for themselves.

• Zoe Williams is a Guardian columnist