A post-mortem of the French 2017 presidential election, 1/2

Deux derniers billets en anglais sur l’élection présidentielle, et désolé si vous avez vu passer le brouillon de ce billet dans le flux RSS ou sur Twitter en avance de quelques jours. Aujourd’hui, première partie, où l’on apprend – scoop ! – que je n’avais pas prévu les résultats du premier tour. Suite et fin quand j’aurai terminé de trier mes sources.

tl;dr: I suck at electoral predictions, but that’s alright (and hardly new).

Before going further, let me disclose here that, after discovering that I was still registered to vote (…), I voted for Benoît Hamon, having always voted for the Socialist candidate when voting in France (I have also voted in Scotland; different story).

Let me also underline that, unlike my guesstimates, French opinion polls performed extremely well in the first round of this election, in line with their good – albeit, by some aspects, bizarre – historical record:1

The graphic above shows both governing parties (Socialists and Republicans) losing their candidate on the first round of a presidential election—which is unprecedented, and a potential transformative event for French politics, which had organised around a two-party quasi-duopoly. As of today, and for a few years at least,2 that status quo is gone:

Make sure to read Fabien Escalona and Donatien Huet’s analysis of the vote – in French, subscription required – to understand the details of the French political order.3 And to further understand how the French extreme-right Front national might now think of its position in that order, I recommend this op-ed by Florent Gougou, also in French.

Electoral post-mortem

I have blogged quite a lot about the ongoing French presidential election. Two of my earlier posts contained attempts at guessing the respective vote shares of Marine Le Pen, the candidate of the extreme-right Front national, and of Emmanuel Macron, a former minister of the outgoing government and the candidate of the centrist En Marche ! movement.

Both guesstimates were for the first round only, which is why I am posting this post-mortem now and not later. I did not produce similar second-round guesstimates because I do not believe that my guesstimation technique, which was based strictly on past electoral performance, can produce anything reliable about the second round; however, my first-round predictions should have resulted in a second round between Marine Le Pen and François Fillon, the right-wing candidate.

For more 2017 presidential election posts, click on this tag. Most topically, here are my electoral ‘pre-mortems’ (in French): pre-mortem, part 1, pre-mortem, part 2.

First-round turnout

  • Assumed 80%
  • Actual 77.7%
  • Δ = –2.7 percentage points

Both of my guesstimates assumed a turnout rate of 80%, based on the hight turnout rates of many past presidential elections. The actual turnout of 77.7% and the 950,000 blank or null votes in the first round reduced the effective electorate to 36 million voters, which is barely 200,000 more voters than the first round of the previous presidential election.

First-round vote for Marine Le Pen

  • Guesstimated 20% (lower bound)
  • Actual 21.3%
  • Δ = +1.3 percentage points

My guesstimate of Marine Le Pen’s vote share put her at a strict minimum of 19-21% of the vote, assuming a turnout rate of 80%. This guesstimate was based strictly on the past electoral performance of the Front national in 2012 and 2015.

The same blog post included a computation of the minimum raw votes for Marine Le Pen of roughly 7 million out of 45 million registered voters from the 2015 regional elections. The correct total number of registered voters in 2017 (47 million) was published only after I posted my guesstimate.

In the end, Marine Le Pen attracted 7.6 million votes, which makes my guesstimate pretty spot-on, largely thanks to the fact that my two computation mistakes (underestimated number of registered voters, overestimated turnout) partly cancelled each other out.

My guesstimate of Marine Le Pen’s vote share was conservative in comparison to what polls (and friends) announced: see, for instance, the better informed estimate of 21-28% by my dear friend-and-co-blogger Joël. Generally speaking, Marine Le Pen’s first-round electoral performance was clearly below expectations.

First-round vote for Emmanuel Macron

  • Guesstimated 18.5% (upper bound)
  • Actual 24%
  • Δ = +5.5 percentage points

My guesstimate of Emmanuel Macron’s vote share put him at a strict maximum of 7 million votes, or 18.5% of the vote, assuming a turnout rate of 80%. This guesstimate could not be based on the (non-existent) past electoral performance of Macron’s movement: instead, I used centrist ex-candidate François Bayrou‘s past record as a proxy for the Macron vote.

In the end, Emmanuel Macron attracted over 8.6 million votes, completely smashing my guesstimate and its corollary—that Emmanuel Macron would not be on the second round of the election, which the polls had – correctly – predicted for several weeks.

My guesstimate was to seriously underestimate the propensity of left-wing voters to flock towards non-Socialist candidates: the official candidate of the party, Benoît Hamon, scored barely 2.2 million votes (6.6% of the vote share), far below left-of-left competitor Jean-Luc Mélenchon, and far below Emmanuel Macron himself.

The first-time-ever component of the election – a (Socialist) president not seeking reelection – certainly played a role in making left-wing voters much more volatile than I would have ever imagined, but my guesstimation technique would probably have been excessively conservative even absent of that factor.

First-round vote for Jean-Luc Mélenchon

In the last two weeks before the first round, opinion polls announced that far-left Jean-Luc Mélenchon was doing really fine with potential voters, and could potentially steal François Fillon’s predicted third place, after Marine Le Pen and Emmanuel Macron. Some of my friends asked me about this, and asked for a guesstimate of his vote share.

To do so, I took his best electoral performance ever, which was his 2012 presidential election performance, where he received almost 4 million votes (11% of the vote share). Note that, at the time, Mélenchon was already supported by the same far-left coalition as he was in this election.

I then formulated three assumptions: stable voting behaviour among his past electorate, identical turnout, and uniform gains among newly registered voters, i.e. 11% of 80% of newly registered voters voting for Mélenchon. That gives you an estimate of 0.11 × 47 = 5.17 million votes, which is a huge increase of over 1 million of new Mélenchon voters since 2012.

This guesstimate of almost 5.2 million votes for Jean-Luc Mélenchon was my upper bound, because under lower turnout, one should expect the far-left vote to decrease, not increase. Furthermore, even a highly dynamic political party like the Front national did not register such an increase in raw votes between 2012 and 2015.

The staggering error in my guesstimate says something of how successful Jean-Luc Mélenchon was at attracting the left-wing vote in the first round of the election. The only correct part in my guesstimate was that he had no real chance of making it to the second round, and was instead competing for the third – and potential “kingmaker” – position.

Last first-round observations

The unusual setup and highly eventful nature of the French presidential election made it a very interesting event to follow, and many observers, including Alexandre Afonso, Jules Bonnard and Mathieu Gallard, provided first-class live reports of what was happening.4

My favourite visualization of the first-round results is this map by Alexandre Léchenet, which shows the modal (first-among-voters) candidate over geographic areas resized to their relative population:

This map is helpful to realise some of the most powerful social cleavages behind the vote: Emmanuel Macron clearly owes a large electoral debt to the urban middle class, which is more educated and therefore also more likely to vote.

  1. Note that my general views about opinion polls, which use nonrandom samples, are insensitive to high polling accuracy on one or more event(s). []
  2. The next ‘intermediary’ elections will take place in three years, and the next presidential and legislative elections in five. []
  3. For complements, see also this article (in French) by Simon Labouret and Florent Gougou, as well as Pierre Martin’s electoral reports (also in French), published in Commentaire. []
  4. Of course, the electoral campaign and first-round results also produced its fair share of implausible counterfactuals, useless fantasy maps and ecological fallacies. Too bad. []

2 réflexions au sujet de « A post-mortem of the French 2017 presidential election, 1/2 »

  1. Ping : A post-mortem of the French 2017 presidential election, 2/2 | Polit’bistro : des politiques, du café

  2. Ping : Dernières choses sur l’élection présidentielle 2017 | Polit’bistro : des politiques, du café

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