Caplan Notes 3/29, Pub Choice II

Official course notes reference. Related: My proof of markets as an optimal voting system.

Important note: His version of ‘expressive voting’ is not the same as the concept (of the same label) which I learned in undergrad from Jonathan Slapin. Caplan’s expressive voting means non-instrumental voting, while Slapin’s expressive voting means voting in a way that communicates your desires more precisely.

Caplan’s version can be found going back to Brennan and Buchanan (1984). More recent discussion is found in Mackie (2011). It says ‘instrumental voting is voting to affect policy, but expressive voting results in utility gains for other reasons.’ So people don’t vote for instrumental reasons in this sense, but they vote for utility from expression.

Slapin gave sources at the time of his class but I don’t recall them. Retrospectively, I found some sources which leverage this concept, but I think Slapin’s sources were older. Voteup, Heather et al (2010), and perhaps Smith (2000) seem to use the term in the Slapin way. Hillinger (2004) seems to use the Slapin idea but gives a different label for the concept: Evaluative voting or utilitarian voting. My preference would be to use the term ‘evaluative voting’ for the Slapin concept, since multiple terms will prevent confusion and the other term was already claimed by Brennan and Buchanan.

I don’t want to call the Slapin concept ‘utilitarian voting’ because it does not in fact logically optimize on utility. It can overcommunicate preference in an unconstrained way which is interesting and revealing, but not socially optimal. Socially optimal voting, in the way an economist thinks about it, would require individual-level budget constraints. The effect would be to weight each voter by their constrained willingness to pay. This would optimize social calculation as it in effect weights the votes of more productive folks more heavily, resulting in socially optimal calculation. Group calculation would be worse if those with low willingness to pay were weighted heavily because that low willingness indicates that they don’t care or they aren’t very productive. Either of those two states would correlate with a person less able to make a good calculation, so their votes should be discounted.

Without constraining the vote according to willingness to pay (that is, without using a market), a voter can express unconstrained preference. Unconstrained preferences are cool because we may get a better idea of an individual’s bliss point. The bliss point may not be revealed when the budget constraint is enforced. However, unconstrained preferences at the individual level lead to inefficient allocation at the social level. A person may vote for a pro-life candidate, revealing an enormous value of human life, perhaps to the tune of millions per life saved. However, if they really had millions they could save many lives by donating to the local hospital. The “problem” is that they don’t have millions…but this is not usually a problem as their lack of millions is (by correlation, not necessity) an indication that they are probably not very accurate in their calculations anyway.

More notes on voting:

  1. I previously thought that expressive voting shows degree of preference in contrast to ordinary voting which only shows fact of preference, not magnitude (eg continuous indicator vs boolean/dummy).
    1. I thought of expressiveness in other words as ‘the ability of a particular method of voting to disclose the exact desires of a voter.’
    2. eg Jim and John want X, but Jim wants more than John. This can’t be revealed under ordinary voting in the US, but can be by an expressive system like range, rank, or other kinds of voting. As mentioned above, I will now prefer to call this evaluative voting.
  2. I think the market is the ideal method of utilitarian voting
    1. And utilitarian voting is better than any other kinds of voting: Expressive ignores instrumental effects and leads to rational irrationality. Evaluative gives calculations based on unconstrained preference which leads to overvaluing pretty much everything. Utilitarian voting administers the budget constraint to preferences, forcing the individual to decide between trade-offs.

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