Assume that two people are playing a game of chess. One player (A) begins with the full compliment of pieces, from Queen to Pawn. The other player (B) begins with a disadvantage, missing a few pawns and even larger pieces.
The two players continue their game seriously. Eventually, Player A wins. The question, then, is who is the better player ?
Is Player A neccessarily the better player just because he won ? Remember that he started with a significant advantage -- his victory could mean that he won by merit of his advantage, not by merit of his skill.
However, this in itself not a reason to believe that Player B is the better player. Maybe his loss was genuinely because of his inaptitude.
The conclusion, then, is that our ability to judge which player is better is severely impaired by the uneven conditions. Clearly, it would be easier to judge if the game was started with both players having equal number of pieces.
For the astute reader, the above analogy is in response to a comment by PAP chairman Lim Boon Heng, who said 'Use same yardstick to judge PAP, opposition candidates'. I admit that we should fairly use the same yardstick in judging candidates, but it is very difficult to come to useful conclusions when the playing field is uneven.
Then again, there have been cases where Player B has defeated Player A consistently. I leave it to the reader to draw his own conclusions.