Since Carwyn Jones announced that he would stand down as Welsh Labour leader and First Minister before the end of the year, only one person has declared their candidacy for the race to succeed – Jones’ Welsh cabinet colleague, Mark Drakeford. While others have indicated that they are considering standing, or might stand, everything suggests that Drakeford will start the race as strong favourite.

But there are two good reasons to be cautious about assuming that we already know the identity of the next first minister of Wales. The first is simply the length of the envisaged contest. A lot can go wrong in seven months – and particularly if you are the front runner, whose every action will be scrutinised closely, and every slight mistake seized upon by critics and opponents.

The other reason to be cautious, however, is simply that certainty is never wise when the available evidence is not good enough. And the available evidence about the current state of the Welsh Labour leadership race, never mind where it will be by December, is limited and of rather poor quality.

We don’t yet know the full field of candidates. We also don’t know what the electoral system will be. The recent Welsh deputy leader contest was conducted under an electoral college system, in which the rank-and-file party membership were given only one-third of the total vote. However, this resulted in the winner, Carolyn Harris, receiving less votes from party members than her defeated rival, Julie Morgan. Meanwhile, the last two UK-wide Labour leadership contests used the One Member One Vote (OMOV) system (albeit with some complications regarding affiliate members and registered supporters).

Which electoral system should be used in future is now a matter of substantial internal party debate. If Welsh Labour is to move to OMOV to elect their new leader, the rule book will need to be rapidly rewritten.

Then there is the view of the electorate itself, although it is weighted towards party members. We currently have little hard evidence on its preferences. And we are unlikely to be able to get much more high-quality evidence over the next few months.

If the new leader is chosen via an electoral college, one-third of the total vote will go to elected Labour parliamentarians: the 29 Welsh Labour assembly members, the 28 Welsh Labour members of the UK parliament, and the party’s sole member of the European Parliament. Many of these 58 people can be expected to make public declarations of support.

Although we have no guarantee that what is said in public will match what is done in the privacy of the postal ballot, past experience suggests that public declarations of support are an accurate guide to the views of this part of the electorate. In the 2009 Welsh Labour leadership contest, which also used an electoral college, the level of public endorsements from parliamentarians closely matched the actual vote shares (see the below table).

Candidate N of Endorsements (%) % Election Vote Carwyn Jones 24 (50.0%) 50.9% Edwina Hart 13 (27.1%) 28.3% Huw Lewis 11 (22.9%) 20.8%

Public declarations of support from fellow politicians should give a good indication of how a particular candidate is likely to fare in that part of the electoral college – if that is the electoral system that Welsh Labour ends up using.

But another one-third of the vote in any electoral college would be with “affiliated organisations” – mainly trade unions that are affiliated to the Labour party. Unions no longer cast a block vote on behalf of their members, but instead run their own ballots of members who have paid a political levy.

In 2009, 11 unions or other affiliated organisations publicly endorsed candidates: however, their endorsements did not necessarily match the vote share enjoyed by the candidates through the union ballot.

Candidate N of Endorsements (%) % Election Vote Carwyn Jones 4 (36.4%) 51.3% Edwina Hart 6 (54.5%) 33.9% Huw Lewis 1 (9.1%) 14.8%

The number of union endorsements may be a poor guide to how a candidate would do in this part of the electoral college, but adjusting for the size of the unions endorsing candidates would not get us much further. In 2009, one of the two largest unions, Unite backed Edwina Hart, while the other – Unison – endorsed Carwyn Jones.

Labour party members in Wales will also have a major say in the choice of their new leader. At the very least, they will constitute one-third of the electorate, and under OMOV rules they (along with political levy-paying trade union members who chose to take part in the ballot) would comprise all of the electorate.

In the last two UK Labour leadership contests, YouGov polls of party members have proven to be strikingly accurate. However, there will be no such evidence available in Wales this time. While the YouGov panel in Wales is the largest of any online political pollster, it does not include enough Labour party members for any serious polling to be done.

Might there be other sources about the views of the membership? Individual Labour constituency parties may offer endorsements of leadership candidates. However, these may prove a rather poor guide to the views of the rank-and-file. In 2009, in Wales, the pattern of constituency party endorsements did not match closely the membership ballot:

Candidate N of Endorsements (%) % Election Vote Carwyn Jones 5 (33.3%) 53.7% Edwina Hart 6 (40.0%) 25.3% Huw Lewis 4 (26.7%) 21.0%

More recent evidence from the last two UK Labour leadership contests suggests something similar. The tables below show the patterns of constituency party endorsements in both 2015 and 2016 compared to the actual vote shares in the leadership election (please note that I have used here the reported vote-shares among party members only, and have not included votes from registered supporters or affiliate members):

2015

Candidate N of Endorsements (%) % Election Vote Jeremy Corbyn 152 (39.0%) 49.6 Andy Burnham 111 (28.4%) 22.7 Yvette Cooper 109 (27.9%) 22.2 Liz Kendall 18 (2.6%) 5.5

2016

Candidate N of Endorsements (%) % Election Vote Jeremy Corbyn 285 (84.3%) 59.0 Owen Smith 53 (15.7%) 41.0

In short, constituency party nominations appear to have only a very loose relationship to how the party members actually vote in Labour leadership elections.

Mark Drakeford is clearly the current favourite to succeed Carwyn Jones. But that standing is based, in the main, on quite poor quality evidence: gossip, rumour, and the public declarations of support of several assembly colleagues. There is no substantial evidence favouring any of his potential rivals. But the wisest course is probably still to view the eventual outcome of the Welsh Labour leadership contest as being uncertain, no matter who ends up in the race.