Who benefits from 0-seat Socialist, Nationalist or Green parties? - PollsPosition

Is one party's loss another party's gain?

What happens if the Socialists, the Greens or the Nationalists get no seat on May 26?

By Alexandre Andorra

On 04/24/2019

You probably know that a consortium of scientists managed to unveil to the world the first image of a black hole . But you may not know that this effort was made possible in large part by the python programming language - which we use to make this website and our models. As a tribute to this wonderful discovery, let us manipulate space-time and analyze parallel universes: those in which some parties get 0 seat on May 26.

We will focus on the three parties that have a substantial chance of winning 0 seat - Greens (2%), Socialists (27%), Nationalists (58%). For example, what happens in universes where Socialists (PS) have 0 seat? Who benefits from it? Does this even make a difference, given the small number of votes expected for the PS (about 6% in our model ) ?

By the way, how do we get these different universes? In short, our model simulates hundreds of thousands of elections - as if the election were taking place at the same time in hundreds of thousands of parallel universes.

Without the Socialists, the left is weaker as a whole

Let's start with the Socialist Party, because we like Latin proverbs, and who better than it illustrates the proximity of the Tarpeian rock and the Capitol? In power from 2012 to 2017, the PS now has more than a 1-in-4 chance of getting 0 seat in the European Parliament, according to our model and the available data. So what are the scenarios, if this happens? In other words, who benefits from an absent PS?

The graph below gives you a quick overview. You know it if you check our forecasts regularly, but we've added some small goodies. The dotted lines represent the range of seats that the party will get 5 out of 6 times when considering all universes. This is simply the graph you see on our forecast page: we look at the whole range of possibilities.

The solid lines, on the other hand, restrict our field of vision to universes where the PS gets 0 seat. You can quickly see the effect of his absence on the other parties, since the two confidence intervals are comparable. Finally, you can change the absent party with the small menu on the right.

Solid line: a given party's potential seats in the given universe.
Dashed line: a given party's potential seats, all universes combined.
Each line represents the range in which the true number of seats is with a 5 in 6 chance (83%).
When a party gets less than 5% of the votes it gets 0 seat, which explains the threshold observed for the trailing parties (they either get 0 seat or at least 4 seats).
Why take a 5 in 6 chance as benchmark? Look at it as the probability of getting any number but the 6 when throwing a fair die. Hover over the chart to see the details.

Now, what can we learn from them? First, the winners are the top three parties (center LREM, far-right RN and right LR), whose interval is shifted one seat to the right - for example, from [16-22] seats for LREM to [17-23]. In other words, they have the same uncertainty - the intervals’ width stays the same - but they have one more seat in the end.

It may seem counter-intuitive to see these three parties - notably LR and RN - taking advantage of the absence of the PS. But this gives me a good opportunity to highlight that we cannot establish causality here: the absence of PS does not cause the increase of the three leaders - the movements are simply correlated.

Why? Because an election is determined by many factors, which influence the result, but also interact with each other. Perhaps a world where the PS has no seat highlights a discouragement of left-wing voters? A world where they do not vote, leaving the center and the right to outperform, without the latter increasing their electoral base. In short, all parties are correlated, but they are not perfectly communicating vessels - there is loss, due to various external factors.

As a matter of fact, the other left-wing parties do not take advantage of the absence of PS: the Greens (EELV) do not move and far-left LFI sees its upper bound increasing by one seat, but its overall uncertainty increases - its confidence interval is wider than in all universes. In other words, a poor performance of PS is not necessarily good news for the rest of the left, because such a poor performance has a chance - and a great chance according to our model - of announcing a poor performance of the whole left.

Without the Nationalists, far-right RN gets stronger, while center LREM and right LR grow more confident

Nationalist DLF having the highest probability of getting 0 seat on May 26, the model logically finds more universes without DLF than, for example, without EELV. You get the paradox: if this scenario has a greater chance of emerging, it is also because DLF is weaker to begin with (about 4.6% of the votes in our model) - so we can infer that its absence will have little impact.

The graph above seems confirm it: only RN wins when the DLF is not there (+1 seat). LREM and LR do not increase but their uncertainty decreases - from 16-22 to 17-22 for LREM, from 10-15 to 11-15 for LR - while LFI, EELV and PS do not move. The "Other" category is more uncertain and potentially wins 1 seat.

In summary, in these universes, DLF voters seem to shift mainly to RN and secondarily to peripheral parties. At the same time, LR and LREM voters are less undecided, thus increasing their party's floor, but not its ceiling.

However, these impacts remain very limited, as illustrated by this table:

Chances of finishing first - difference between a given universe and all the universes (baseline)
Chances of finishing 1st (%) LREM RN
Baseline 61.5 25.7
Without PS 0.1 0.3
Without DLF 0.2 0
Without EELV 0.2 0.2

The absence of DLF does not increase the far-right’s chances of finishing first - it has a 1 in 4 chance, as in all universes. More globally, the three universes we are studying do not change much from the baseline: the favorites and the respective chances of finishing first remain the same. The main reason is probably that the leaders are too far ahead of the parties likely to obtain 0 seat, which by definition are the weakest. It would take a huge combination of circumstances, or a very big polling error in favor of the weakest parties for the favorites to be worried.

Without the Greens, the Socialists are not stronger

First, why do we include EELV in this article? The situation of the Green Party is different from that of PS and DLF, since the Greens currently have only a 2% chance of obtaining 0 seat. But they have often been criticized for not forming alliances - especially with the PS. Looking at the universes without EELV, we examine the hypothesis that ecologists steal votes from the PS - if this is the case, the PS should win in universes where EELV is absent. Of course, this comparison is open to criticism - to do it right, surveys with and without EELV would be necessary - but it is already better than doing it without any data.

Again thanks to the graph at the beginning, we can see that the situation is similar to the one where PS has 0 seat: the only ones who really benefit are the three leading parties, all moved from one seat to the right. The upper bound of RN even increases by two seats, which increases its uncertainty but makes it the biggest potential winner of a Green under-performance.

The rest of the left is in the same situation as DLF and the peripheral parties: the upper bound of PS and LFI increases, but the uncertainty increases because the lower bound is constant. To take a metaphor, imagine a room with a known floor and ceiling height. We want to know how high the first secretary of the PS - Olivier Faure for close friends - will be on May 26. What we learn in universes without EELV is that PS has a chance of finishing higher than in all universes, but we don't know more about its true position - on the contrary, since the room is now higher, there are more possible final positions.


But we can do more than dubious metaphors with this analysis of different universes - at least I hope so. In summary, according to our model and the available data:

  1. It would be surprising to see the left-wing parties outperform on May 26 if one of them under-performs. Such an under-performance would probably signal an electorate leaning to the right and center, or a demobilized left-wing electorate. In any case, a bad sign for the whole left.
  2. On the other hand, a poor performance of Nationalist DLF seems to benefit far-right RN and, to a lesser extent, the peripheral parties. In other words, this looks more like a rejection of the party and its leader than a rejection of right-wing nationalism as a whole.
  3. The three parties we studied (PS, DLF and EELV) are too small to have an impact on the hierarchy of favorites - in all universes, LREM is slightly favored, with RN in ambush. It would take several exceptional circumstances or a very big polling error in favor of the weakest parties for the favorites to be worried.
  4. A corollary of this third lesson is that, for the time being, the three favourites can only benefit from the absence of one of the parties studied - either their upper bound increases (greater potential, but greater uncertainty), or their lower bound increases (their voters are less undecided, but their potential does not move), or the whole interval is shifted to the right (net gain of seats, unchanged uncertainty).

Alexandre Andorra is a co-founder of PollsPosition.