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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">Hello!</font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">Really, a big hello to everyone. How long has it been? About a year and a half since my last post, apparently, and then a while longer since I was really a 'regular' here. If anyone feels moved to tell me what they think the most exiting developments on the list have been in the last couple of years, I would be quite interested to hear about it. (No pressure, though :-)</font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">As I've probably mentioned, I'm working on my PhD in economics, and I estimate that about half of my dissertation will focus on voting theory. (There is always the temptation to make it more than half, but I've been told that it will be harder to get a job if I don't spend a bit more time on more traditional topics.) I feel that I'm beginning to reach a stage where I ought to start sharing my work with others a bit more, and stop being stuck in my own head quite as much.</font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">So, I'm writing to say that I have a voting theory paper in a kind of advanced first-draft stage (really it's more of a tenth or twentieth draft, but it probably still has a ways to go before it's finished), and have made it available on the UCSB economics department web site, at: </font></div>
<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;"><a href="http://econ.ucsb.edu/graduate/PhDResearch/phdResearch.htm" target="_blank">http://econ.ucsb.edu/graduate/PhDResearch/phdResearch.htm</a></font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">Your comments, if you have any, will be greatly appreciated. </font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">I'll give you a quick summary here: This paper is the beginning of a project which has the overall goal of developing measures of the vulnerability that different voting methods have to strategic manipulation, that is, vulnerability to strategic voting and strategic nomination. So far, I've been using computer simulations as my primary method of study. The paper describes simulations that I've used to measure the relative strategic vulnerability of seven single-winner voting methods: </font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">plurality </font></div>
<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">two round runoff </font></div>
<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">alternative vote </font></div>
<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">minimax </font></div>
<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">Borda </font></div>
<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">approval</font></div>
<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">range </font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">The gist of my methodology is this: Using a fairly simple model, I generate candidates and voters in S-dimensional issue space. Preferences of the voters over the candidates are determined by relative proximity. To measure strategic voting vulnerability for each method, I calculate initial results based on sincere voting, and then see how often a group of voters can get a mutually preferable outcome by voting strategically. To measure strategic nomination vulnerability, I see how often the withdrawal of a non-winning candidate (or group of candidates, under certain restrictions) changes the outcome. </font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">Perhaps the most conceptually challenging part of this was to write programs for each method (I've been writing my simulations in matlab, by the way) that are able to determine, in every possible case, and for any number of candidates, whether manipulation by strategic voting is at all possible, without having an absurdly long runtime. (Before this, I was completely inexperienced in computer programming, but now I'm at least able to do simulations, if not much else.) The paper goes into some detail about how each program works; I believe that they work correctly, but am happy to hear from anyone who can find a hole somewhere. </font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">I can also tell you a little bit about my preliminary results. The orderings of the methods are somewhat sensitive to the specifications of the model (there are three parameters: N, the number of candidates, NV, the number of voters, and S, the number of issue dimensions), but it is possible to comment broadly on which methods tend to perform well or poorly. </font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">With respect to strategic voting, alternative vote (IRV) is usually the least manipulable, followed by two round runoff, then minimax, then plurality. Approval, Borda, and range voting tend to be the most manipulable, roughly in that order (going from best to worst).</font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">With respect to strategic nomination, I should first say that I didn't bother to calculate vulnerability scores for approval and range, because they are probably very close to zero (under some assumptions, exactly zero), that is, very resistant to strategy. Aside from those, minimax is clearly the best, in the specifications I looked at. Alternative vote is generally better than two round runoff, which in turn is generally better than plurality (plurality is clearly the worst). Borda occupies different places in the ranking, depending on various assumptions, but it is always better than plurality and worse than minimax. However, my simulations agree with existing intuition in finding that Borda systematically encourages more non-winning candidates to enter (what has been called 'teaming'). By contrast, minimax gives no
specific bias in either direction, while the remaining methods have a specific bias that discourages candidate entry (what has been called 'vote-splitting'.)</font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">So, to sum up, speaking very, very roughly,</font></div>
<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">for strategic voting: IRV > runoffs > minimax > plurality >> approval > Borda > range </font></div>
<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">for strategic nomination: approval, range >> minimax >> IRV > runoffs > Borda (varies) > plurality</font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">Especially towards the end, the paper goes into some detail about how this approach can be extended (e.g. more methods, more sophisticated data-generating processes, weighting strategies inversely by how difficult they might be to pull off, etc.), and a few other approaches that can be tried (e.g., for voting, taking the next step beyond finding out whether strategies are possible, and trying to get at what might happen next, finding strategic equilibria, etc.; for nomination, finding the full set of Nash and core equilibria)... again, this is just intended to be a first step.</font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">Again, the full paper (in its current draft) is available online, and again, I'm looking forward to hearing your comments. I hope that everyone has been well, and I hope that I won't be quite so absent from the list as I have been over the last few years.</font></div>
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<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">all my best,</font></div>
<div align="left" style="text-align:left;"><font face="Times New Roman" size="+1" color="#000000" style="font-family:Times New Roman;font-size:14pt;color:#000000;">James </font></div>
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