I've been using Bill James' Win Shares a bit this week
and that's generated quite a few letters asking just
what a Win Share is and how it's calculated. I'll
explain the first and give you a link that better
explains the second.
A Win Share is a single number that covers the whole
shooting match: offense, defense and, if the player in
question is a pitcher, pitching. What is especially
neat about it is that it takes into account context. A
player's home park advantage/disadvantage is factored
into the equation as is the era in which he played or
is playing. This is done by using the number of runs
scored in the player's league as well as the number
scored by his team as a basis of comparison. It's far
more complicated than that, of course, but that's an
easy way to describe it. Some things I especially like
about Win Shares are these:
1. It puts pitching and offense in the same context.
It manages to compare the apple with the orange.
2. It takes into account defense. Do defensive stats
still have a long way to go? Yes, but compared to
where they were 20 years ago, they have already come a
long way and Win Shares does a full accounting of the
3. It cuts through the vagaries of time. The 26 posted
by Pie Traynor in 1925 has the same basic meaning as
the 26 posted by Vernon Wells last year.