Angola 2022: What (effective) seat product and impact on the outcome?

Earlier this week, in trying to understand the Angolan electoral system, I was unsure whether the allocation of the national list seats was compensatory, or in parallel to the provincial district results. In the comments, Miguel was kind enough to quote the relevant sections of the electoral law, confirming that allocation is parallel.

The results show the ruling MPLA won 51% of the vote and the main opposition UNITA 44%. I will take these as given, and not speculate on whether they are the “real” vote totals or a product of “electoral alchemy.” Rather, I am interested in whether the translation of these votes into seats suggests the MPLA chose a system that would benefit it considerably, or not.

The MPLA has won 124 of the 220 seats. That is 56.3% of the seats, for an advantage ratio (%seats/%votes) of 1.10. How does this compare with an “average” electoral system? I checked my dataset, restricting it to “simple” systems, even though Angola’s is not simple, and to those that are not FPTP or other M=1. The average across 377 such elections is… 1.12.

In other words, if the MPLA was trying to give itself a considerable seat advantage from this electoral system design, it kind of failed.

There is certainly one aspect of the electoral system design that looks like “rigging” via the rules: The provincial tier is highly malapportioned. The 18 provinces vary widely in population, yet each elects five members. See the images with preliminary vote totals in another comment from Miguel or see the CNE site, which also includes seats now. Given the use of D’Hondt at this level and the ample margins in rural provinces, the MPLA won 4-1 in several districts (and 5-0 in one)1 and 3-2 in all others aside from the three where UNITA was ahead. (UNITA won 4-1 in Cabinda.)

What undermines the MPLA’s own advantage considerably is the nationwide list component, which constitutes just under three fifths of all the seats (and uses Hare quota and largest remainders). If the MPLA had really wanted to create a system to advantage itself, it could have done so by making this tier smaller, or by various other designs.

I do note that UNITA is somewhat underrepresented. Its 90 seats is 40.9%. Given 44% of the votes, its advantage ratio is 0.928. Across a subset of electoral systems fitting the criteria I referred to above, this is quite low. In fact, the average for second parties is 1.075. (Subset because my dataset does not currently have second party shares for all elections; there are 147 elections here.)

In this sense, the electoral system’s design did indeed punish the main opposition. So if this was the MPLA goal, mission accomplished. The malapportionment must be a main cause of this, combined with the parallel (non-compensatory) allocation of the national seats. It should be noted as well, however, that with only two big parties, if one is overrepresented even a little bit (as the MPLA was), the second will probably be more underrepresented than would be the case in a multiparty system more typical of PR electoral systems.

Interestingly, much of the disadvantage to UNITA went to the advantage of smaller parties instead of to MPLA. There were three other parties, each of which won 2 seats. Two seats is 0.91% of the assembly; these parties had from 1.14% to 1.02% of the votes apiece. These small parties won only in the national district, where the only threshold was that a party could not win a seat by remainder unless it had already won a seat.2 Given that the national district is 130 seats, it could easily have supported even more parties than the five that won at least 2 seats. The largest party to win no seats had 0.75%. A simple quota for this district would be 0.769%, so this party was below the weak threshold anyway.

The effective numbers of parties were 2.20 by votes and 2.06 by seats–note not much difference there.3 The deviation from proportionality (Gallagher’s “least squares index”) was 4.44%. The latter figure, using again my set of simple non-FPTP systems, is not much different from average (4.87%). So all in all, despite the unusual electoral system, it is not a terribly remarkable result in terms of election indices.

As far as the effective seat product is concerned, for a parallel system I have found the satisfactory method is to take the geometric mean of what we would get if the basic tier were the entire system and what we would get if the system were compensatory. The seat product of the basic tier of this system is straightforward: district magnitude of 5, times tier size of 90 gives us 450. The formula for compensatory based on these parameters (an update and slight modification of a method I have shown here before) would yield an effective seat product of 3844. But because it is actually parallel, we take the geometric average of these values, which is 1315.

An effective seat product of 1315 is in the general range of the simple seat product Norway had (1297) before it adopted a small compensatory tier after 1985, or Peru’s in 1980 or 1985 (1296), and also not much smaller than Switzerland’s (1540).4

The disproportionality we should expect from an effective seat product of of 1315 would be around three percent; the actual 4.4% is thus not too much higher. The seat share of the largest party in this election is about 1.4 times expectation5 from such a seat product and the effective number of seat-winning parties is about 0.62 the expectation. Obviously, this is due to MPLA political dominance. Or perhaps due to unfair vote reporting. That I can’t say. What I can say is that, despite a fairly unusual combination of extreme malapportionment in one tier and a greater than 50% parallel national tier, the impact this electoral system had on the seat allocation and disproportionality was not anything too out of the ordinary.

Finally, an interesting question but one I will not attempt to answer is whether, had UNITA won a narrow plurality of the nationwide vote, could the MPLA have retained a plurality or even majority of the assembly seats? Given the malapportionment and parallel allocation, I will say maybe. However, once again, I will point out that if they had wanted to ensure they could “win by losing,” the design they came up with was perhaps a little too “fair” to really be in their best (presumed to be anti-democratic) interest. On the other hand, if they are open to a gradual transition to democracy, and perhaps losing a fair election in five or ten years’ time, the system isn’t too bad. It plays to the MPLA’s regional strength yet does not overrepresent it greatly, and it creates space for the opposition, both UNITA and other parties, to operate.



  1. MPLA won 4-1 in Cuanza Sul, Moxico, Namibe, Huíla, and Cuando Cubango. It won 5-0 in Cunene (where the votes split 82.9%–14.4%). It is really striking that most of these strong MPLA districts are in the south, where UNITA was most present in the civil war. Meanwhile, the UNITA pluralities are Luanda (the capital and largest by far), Cabinda (the non-contiguous oil-rich enclave in the far north which has had a separatist movement) and Zaire (also in the northwest).
  2. It is not clear to me if this means a party could have won a provincial seat and thus been eligible for a remainder seat in the national district, or it had to have won a quota of nationwide votes. In any case, as all provincial seats were won by MPLA or UNITA, this detail would not have affected the results of this election.
  3. If I knew nothing other than that the effective number of vote-earning parties in some election was 2.2, I would expect the effective number of seat-winning parties to be around 1.72, based on logically derived, and empirically supported, formulas in Votes from Seats.
  4. By comparison, if we used the “as if compensatory” estimate of 3844, we would be in roughly the range of single-tier systems like Finland (3076 in 2019) or another former Portuguese colony, East Timor (4225). Indonesia is also in this seat-product neighborhood (4134), as was the French PR system of 1986 (3174).
  5. A ratio of actual to expected of 1.38 is near the 90th percentile for over a thousand elections, simple and complex, in the dataset (and would be about the same if I looked at just the simple non-FPTP subset).

10 thoughts on “Angola 2022: What (effective) seat product and impact on the outcome?

  1. A question related to this sentence: “The seat share of the largest party in this election is about 1.4 times expectation5 from such a seat product and the effective number of seat-winning parties is about 0.62 the expectation.” I understand from your previous post that “the voters have only one vote, and that the leader of the party with the most votes becomes president”. Couldn’t that be the reason the effective number of parties lower than expected and the share of the largest party bigger than expected? There is strong political incentive for parties to coalesce into 2 major blocks in the parliamentary elections, in order to increase their chances of winning the executive.
    This is also interesting in a completely different context: Israeli electoral change proposals. Yet another such proposal – proposed by the NGO “Israeli Democracy Institute” was to have the leader of the largest party in the Knsesset after the elections, become prime minister automatically. This is thought to encourage the exact same result – coalescing of the parties into 2 major blocks, the larger of which would win the executive and avoid the prolonged political crisis. I wonder if that is a good idea and what the Angolan example can teach us about its possible outcomes.


    • It is possible, but I would not have any such strong expectation. I suspect if there had been separate votes, it would not have made a great deal of difference to the sizes of MPLA and UNITA, because these are the two major political forces in the country.

      To put it another way, even if allowing ticket-splitting had the effect you ask about, I’d guess the MPLA would have been larger than expected from the seat-product model (albeit perhaps by a lesser degree).

      As for the IDI’s proposal, I’ve told some friends there that I think this is somewhere between a bad and a no-effect idea. Bad in that if it “works” it becomes a new form of direct election. No-effect in that the proposals I have seen still allow a majority of the Knesset that prefers a different PM to put their candidate in office immediately after the election–as indeed it must unless one wants to adopt a presidential system. I doubt it would have much effect on voting patterns or outcomes, although it might “re-presidentialize” the leading parties, which would be a bad thing.


      • Thank you for your reply. I get that the political landscape was already dominated by 2 parties, but I still wonder if the single ballot could not have influenced voter preference even more towards those 2 parties. When the leader of the largest party becomes president, voting for a minor party is in fact abstaining from voting for the presidency, so your vote “counts” less. It seems a powerful incentive to vote for one of the major parties, closer to your political preference, even if otherwise you would have preferred a more niche party, which, with a large proportional representation national level, could have been a meaningful vote if not for the issue of electing a president at the same ballot. I wonder if there is evidence of such an effect in other single-ballot systems, if such exists.

        Liked by 1 person

        • Thank you; I appreciate the question. As I said in the previous response, I agree with the possible effect. I just do not think we should assume it is a large effect in general, and even less should we assume it was a significant factor in the Angolan situation.

          Evidence would be hard to come by, because the fused ballot is fairly uncommon in presidential systems, and it would also be hard to draw inferences even from the cases and changes in rules that we have. For instance, it is true that the first election (or perhaps the first in several cycles) in the Dominican Republic that did not have the fused ballot also featured closer three-way competition than previous elections with fused ballots. But is that a causal relationship? And if so, are we sure the causality did not run the other way? (I.e., perhaps the ruling party–which had a majority at the time–changed the electoral law because it saw a third-party challenge coming and expected to benefit from strategic split-ticket voting in the presidential contest.)

          If I get a chance, I am going to try to look into this a little further. You are not the only person who raised this (the other was on Twitter). There may be more to it than I am assuming, although a couple things should be kept in mind: (1) ticket splitting in concurrent presidential–assembly elections is not usually very high, and (2) three-way races are entirely possible, and indeed quite common, under plurality presidential elections. So it is not as if plurality suppresses other parties all that effectively when there is demand for other options, and I am skeptical that a fused ballot is anywhere near as important as other factors that shape the number of serious competitors.


        • I had a chance to look into this question. As I said in the comment above, fused ballots are rather rare, and may be adopted/abolished by ruling parties/coalitions based on expectations of advantage. In other words, the direction of causality between party-system outputs and rules is more ambiguous than usual. With such caveats reiterated, here is what I find.

          This is for pure presidential systems, only because I am not aware of cases of semi-presidential systems that fuse presidential and assembly votes. (In parliamentary systems, the option does not arise, or in a sense the vote is always fused. I did not include the brief case in Israel of separate and direct election of an executive who was still responsible to the parliamentary majority.)

          My outcome of interest is the ratio of expected effective number of seat-winning parties (Ns) or seat share of the largest party (s1) to the expectation, given the seat product of the assembly (first chamber) electoral system.

          For Ns, the ratio in non-fused cases is 1.13, for fused it is 0.927. This looks like good news for the hypothesis that fused ballots restrict party systems more than the separate vote does. However, the difference is not close to significant (p=0.12).

          For s1, the ratio in non-fused is 1.012, and in fused it is 1.047. Obviously that’s not significant. (Also, the seat product model is pretty good–even for presidential systems!)

          Note that for Ns, the mean assembly party system in a presidential democracy tends to be more fragmented than expected from its electoral system. Probably not what most people expect. Perhaps this is driven by the unusually fragmented case of Brazil. If I take it out, the ratios in non-fused are 1.083 for Ns and 1.031 for s1. So not much impact.

          Perhaps one should drop Uruguay from the set of fused cases. Not because ballots are not clearly fused, but because the electoral system is so different. Before 1999, parties could present multiple presidential candidates (and pool votes at party level for determining which party would win), and since then the fused ballot is only for the first round of a two-round presidential election. However, if we do this, we have only four cases left, so it is kind of meaningless. For the record, we would then have about a p=0.1 signifiant result in the expected direction. But I would put no stock in a result comparing four elections (in two countries) in one group to over 150 in the other group!

          This is the list of cases with fused ballots that I am using. If I missed some, please let me know. (Angola, the topic of this thread, is not in the dataset, nor are other countries that are not generally classified as democratic.)

                country   year  
          Dominican Rep   1978  
               Honduras   1993  
               Honduras   1997  
               Honduras   2001  
                Uruguay   1989  
                Uruguay   1994  
                Uruguay   1999  
                Uruguay   2004  
                Uruguay   2009  
                Uruguay   2014  
                Uruguay   2019  

          To this list could be added Bolivia. However, I did not include it because elections for president were not direct before 2005 (congress chose from top three if the popular vote did not yield a majority) and since 1997 the fusion has been only between the presidential vote and the party list vote of an MMP system.


        • I do not have Guyana as semi-presidential, no. Nor did the late Robert Elgie.

          We discussed this rather unusual system in a previous planting. I am not sure we really resolved how to classify it, but it is evidently not semi-presidential.


  2. Pingback: The effects (or their lack) of fused presidential–assembly ballots | Fruits and Votes

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