WORKED NUMERICAL EXAMPLE OF A BAYESIAN REGRET CALCULATION ================Warren D. Smith Nov 2008================= Here is a simple example. 3-voter 2-candidate plurality vote. Table of utilities: candA candB ----------------- voter1 1 9 voter2 4 3 voter3 5 2 CandA wins by 2 votes to 1. Utility=1+4+5=10. If CandB had won, utility would be 9+3+2=14. Because 14>10 there is nonzero regret=14-10=4. Now do it again but with a new table of 6 utility values generated by your random number generator. Table of utilities: candA candB ----------------- voter1 4 6 voter2 1 3 voter3 5 3 CandB wins, utility=6+3+3=12. If CandA had won utility would be 4+1+5=10. Since 12>10 we see regret=0. MEAN regret = (0+4)/2 = 2 (in these two elections) Keep doing it, a zillion times, keeping track of the EXPECTED regret in all zillion election experiments. Result is the mean regret of 2-candidate 3-voter honest plurality voting using whatever utility generator we have.