Costa Rica 2022: Continued high fragmentation

Costa Rica recently (6 Feb.) held its presidential and national assembly elections. In the case of the presidency, it was the first round; a runoff will be needed (3 April), as no candidate came close to the 40% required for a first-round victory. The result shows a continuation of the impressive degree of fragmentation that has occurred in recent elections, following a prolonged period of dominance by two major parties.

I will focus first on the assembly election. The largest party in the new assembly will be the National Liberation Party (PLN), one of those formerly major two parties, but in this election it won only 24.5% of the votes for assembly party lists and 18 of the 57 seats, or 31.6%. That is a one seat gain from what it had in the outgoing assembly, elected in 2018, when it was also the largest party. No other party broke 15%. Six parties have won at least one seat, and a large number of parties obtained vote shares of around 2% or less but no seats.

In terms of effective numbers, for votes this works out to 8.3. Yes, eight point three! That is up there with the world’s highest observed values. In seats, the effective number is 5.02, which is also high but less remarkably so in world comparative terms. For comparison, the 99th percentile of effective number of vote-earning parties from over a thousand elections in the dataset I use is 8.6. On the other hand, Costa Rica’s value for seats in this election is just above the 75th percentile (which is 4.77). Another way of stating this is that Costa Rica is experiencing an unusually large gap between effective numbers of parties by votes and seats. This is not the first time, as the values in 2018 were, respectively, 7.79 and 4.78.

The precise reasons for why the votes are fragmenting so much would require someone versed in Costa Rican politics, which I certainly am not. However, it is obvious that the electoral system is struggling to accommodate the voting fragmentation that is being fed into it, and at at the same time, voters are no longer coordinating their votes around what the electoral system can sustain. That leads to a lot of wasted votes.

This is a new phenomenon for Costa Rica. Over the entire period of the current electoral system, which has been in place since 1962 (the year the current assembly size and the current mean district magnitude (8.14) went into effect), the mean effective number of vote-earning parties has been 3.67, and the mean effective number of seat-winning parties has been 2.97. The mean largest party vote share has been 0.413. The mean seat share for the largest party has been 0.453. So the recent two elections (and to some notable degree those since 2006) have been quite a break with the old “textbook” Costa Rican party system.

A point I wish to emphasize is that the old party system was what we should expect of an electoral system like Costa Rica’s. It is a proportional representation (PR) system, but one with a modest seat product. Its seat product (mean district magnitude times assembly size) is only 464, or a little higher than that of the USA (435). So it should be expected to have a party system with two major parties, one of which averages close to a majority of seats, plus some smaller parties–as indeed the USA should have! And that is what Costa Rica had. The expected outcomes of this system, from the seat product model, would be a mean effective number of seat winning parties of 2.78 (barely below the observed fifty-year mean of 2.97). For votes we should expect 3.17 (not far below the long term observed mean, 3.67). For largest party seat share, we expect 0.464 (nearly matching the observed mean of 0.453); for vote share, 0.421 (actual mean 0.413).

In other words, the longterm party system of Costa Rica is basically what we should expect to see, given the modest value of its seat product. We do not need to invoke a presidential electoral rule that allegedly supports a two-party system, as some scholars have done in the past (hey, including me!). In fact, it is not even clear that the presidential electoral system–40% or runoff–should support two-candidate competition. In some past works I classified it as close enough to plurality, which some folks allege supports two-party systems. Of course, it does. Except when it does not. And the runoff provision makes that “except when it does not” even more accurate a description of the systemic effect. Sure, if 40% in within reach for a leading contender, others may have incentive to coordinate and try to beat the leader to 40% When the PLN was politically dominant, that was exactly what the game was. But when expectations are that no one will get to 40%, all bets are off, because to a significant degree political forces can coordinate between rounds, rather than before the first one.

In Votes from Seats (2017), Taagepera and I showed that we can actually predict presidential vote fragmentation from the assembly seat product better than we can predict it from either the rule used to elect the president or the actual number of competitors in the presidential election. And Costa Rica was, until recently, a great demonstration of that effect, with (as noted) an assembly party system that was a near perfect fit for the assembly electoral system’s seat product. The presidential party system followed right along, as expected, with a mean effective number of presidential candidates of 2.5 since 1962. The predictive model Taagepera and I propose in our 2017 book suggests that with Costa Rica’s seat product, the effective number of presidential candidates should average 2.49–so there was basically perfect prediction of Costa Rican presidential competitiveness. However, something clearly has upset the old equilibrium.

In this election, the effective number of presidential candidates was 6.15! For comparison, this is almost the 99th percentile of over 200 presidential elections from around the world in the dataset (6.25). [Update: see my own first comment below.] The leading candidate, José María Figueres had only 27.3%. His opponent in the upcoming runoff, Rodrigo Chaves Robles of Social Democratic Program, won 16.7%, and three other candidates had between 12% and 14.8%. The party of outgoing President Carlos Alvarado, Citizens Action, collapsed, with its candidate getting only 0.66% of the presidential vote (and 2.2% of the assembly vote, and no seat–in 2018, despite winning the presidency it had won only 10 seats, good for third place; further, presidents are not eligible for immediate reelection in Costa Rica).

The level of fragmentation of the presidential vote in 2022 is an increase over 2018, when the effective number of presidential candidates was 5.51, and the leading candidate (who lost the runoff) had just under 25%. It is the third election in a row in which no candidate broke 31%. (In 2010, the leading candidate who was from the PLN, won without a runoff, getting just under 47%.)

While on average, the seat product model leads us to expect presidential systems to have assembly party systems similar to what their seat product predicts, and a mean presidential competition also predictable from the seat product, individual elections can upset this. That is, short term presidential politics–who is entering competition and who is seen as a viable presidential candidate–can shock the assembly party system, due to a “coattail” effect. So we generally get longterm predictability from the assembly electoral system’s seat product, but short term disruptions from “presidentialization” of competition. This is now Costa Rica’s third consecutive election with effective number of seat-winning parties over 4.5. That seems unsustainable, based on the electoral system. But at some point maybe a short-term shock settles down and becomes the new normal. I guess we will have to wait till at least 2026 to see if the seat product reasserts itself, or if fragmentation really is the norm. And not just any fragmentation, but an exceptionally high level by world standards, particularly in the votes for both assembly and president.

7 thoughts on “Costa Rica 2022: Continued high fragmentation

  1. Update after a deeper data check. The 2022 Costa Rican effective number of presidential candidates could be the highest ever. The only higher values were for Finland in the 1970s, but at that time Finland did not technically feature competition among presidential candidates. Voters voted in an election for an electoral college that was elected much like the national assembly (albeit it was larger, so its seat product was higher).

    In the dataset (for which presidential elections have not yet been updated later than about 2011 while I focus my updating on assemblies) the only cases of effective number of presidential candidates above 5.0 are Brazil 1990 and Croatia 2011. Costa Rica now would have two additions to that list.

    So what we are seeing there is truly remarkable. (See also the comment I put in immediately below this one.)


    • Correction: I just realized that France must have some even higher, but French presidential elections are not currently in the dataset I was using.

      Indeed, France reached 5.95 in 1997 and 8.65 in 2002! My presidential-elections dataset also shows a Zambian election over 5.0 (in 2001, 5.08).

      I also note some elections in Ecuador that are higher than Costa Rica 2022, including 2002 with 6.84!


  2. Costa Rica has a very small legislature considering it’s population size. According to the cubic root, it has a population of 5 million, and thus would a legislature of 171 members. Other than Belize, Costa Rica has the smallest sized legislature for a Central American country.


  3. Costa Rica has an electoral threshold equivalent to half a Hare quota in each district. Most districts outside of San Jose have a relatively low magnitude, so that causes a significant distortion in the results.


    • The low magnitude of most districts inflates disproportionally, yes, when the votes are not adjusted to the seats. As I noted in the post, they were so adjusted for many decades, resulting in both votes and seats close to prediction. Granted, the seats were already closer to expectation than the votes: ratio of actual to expected effective number being 1.07 for seats and 1.16 for votes over the long term.

      The threshold would not have much impact; 1/2M is pretty low, and in most of those low-magnitude districts would likely have no effect. However, the higher the votes fragmentation the more it could matter. This could be investigated with detailed district-level data, although I am not likely to do so myself.


  4. Great analysis! One comment: I got the same effective number with regards to seats (5.02) but the effective number for Legislative votes gives me 7.64 (Laakso and Taagepera), based on the Supreme Electoral Tribunal data.
    Are you using a different formula? Probably I’m doing something wrong. Thanks for your Fruits and Votes inside!


  5. Pingback: Biden's White House Makes a Telling Mistake – Bloomberg – UK NY news

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