Specific Tastes or Cliques of Jurors? How to Reduce the Level of Manipulation in Group Decisions?
- PDF / 1,105,442 Bytes
- 28 Pages / 439.37 x 666.142 pts Page_size
- 5 Downloads / 190 Views
Specific Tastes or Cliques of Jurors? How to Reduce the Level of Manipulation in Group Decisions? Krzysztof Kontek1 · Honorata Sosnowska1
© The Author(s) 2020
Abstract We propose a modification of the standard Borda count which significantly reduces the level of manipulation demonstrated in experiments and observed in actual voting. The method may be applied in voting systems in which the Borda count is usually adopted, e.g. musical competitions, elections in educational institutions and professional and technical societies, sports awards, and even some political elections. We first analyze the actual voting results in the 2016 Henryk Wieniawski International Violin Competition. We show that some jurors are suspected of having exploited a weakness in the standard Borda count method to manipulate the final results. We then consider modifications of the Borda count with a view to designing a method more resistant to manipulation. We show that discarding all the scores of the 20% of jurors who deviate most from the jury average gives a ranking that agrees with public opinion and general expert consensus. Modifications of the Borda count were then experimentally tested against their resistance to manipulability. The results clearly show that excluding jurors has very good statistical properties to recover the objective order of the contestants. Most importantly, however, it dramatically reduces the level of manipulation demonstrated by subjects playing the role of jurors. Finally, we present the mathematical properties of the method proposed. We show that the new method is a compromise between the Majority Criterion and the standard Borda count in that it offers more “consensus-based” rankings than the former while being less vulnerable to manipulation than the latter. Keywords Borda count · Strategic voting · Resistance to manipulation JEL Classification D01 · D02 · D71 · D72 · D82 · D85
* Krzysztof Kontek [email protected]; [email protected] Honorata Sosnowska [email protected] 1
Warsaw School of Economics, Al. Niepodleglosci 162, 02‑554 Warsaw, Poland
13
Vol.:(0123456789)
K. Kontek, H. Sosnowska
1 Introduction Scoring and voting systems are described in the literature on social choice theory (review in Arrow et al. 2002; Nurmi 1987). This theory covers areas such as Arrow’s (1963) impossibility theorem, voting systems analysis, the structure of the (collective) social choice function, individual rights theory, and justice theory. Arrow’s famous impossibility theorem states that there is no such thing as a “fair” voting system. We can, however, search for systems that have beneficial properties. There is a wealth of literature on voting methodology, although it is generally concerned with political elections (e.g. Austen-Smith and Banks 2002). There is, however, a paucity of literature on scoring and voting systems in music competitions, and what little there is mainly deals with the factors that influence the final scores, e.g. order of appearance, the sex and country of origin of the
Data Loading...
