WHO OUGHT TO BE ELECTED AND WHO IS ACTUALLY ELECTED - AN EMPIRICAL-INVESTIGATION OF 92 ELECTIONS UNDER 3 PROCEDURES

Three voting procedures - Borda's Count (BR), Plurality Voting (PV), a nd the Single Transferable Vote (STV) - are compared with one another in relation to the outcomes of 92 real elections conducted in Britain by various trade unions, professional associations, and non-profit org anizations. Given the social preference ordering (SPO) among the n com peting candidates, of whom m candidates must be elected (n > m greater -than-or-equal-to 1), each of these procedures is evaluated by means o f two new indices that measure the discrepancy between the m candidate s elected and the prescription of the majoritarian principle. For two of these procedures (PV and STV), we also investigate the relative fre quency with which they display the recently discovered Discontinuity P aradox, namely, cases where a candidate who would be elected when m ca ndidates must be elected would not also be elected, ceteris paribus, i f m + 1 candidates were to be elected. Our analysis supports the follo wing three conclusions: (i) When m = 1, STV (or rather its Alternative Vote variant) conforms better with the SPO than do the other two proc edures, particularly PV. (ii) When m > 1, BR conforms with the SPO sig nificantly better than do the other two procedures, particularly STV. (iii) PV is likely to display the Discontinuity Paradox more often tha n STV. Since BR is not susceptible to the Discontinuity Paradox, we co nclude that, in terms of avoiding this paradox and conforming with the SPO, BR performs better than both PV and STV.