How strong is the correlation between WAR and wins?

After every offseason move, baseball analysts (like myself) attempt to evaluate how many “wins” each team gains.

Usually, the exercise is rather simple. One can look at projected WAR for the players currently on the roster, re-estimate the amount of play time for each player and then determine how many wins the team gained from their new addition. For example, with the addition of Andrew Miller, we can estimate that the Cardinals should be about 1.5 wins better. That’s pretty a significant improvement from a relief pitcher alone, and it serves as a testament to Miller’s success.

The problem is that this assumption rests on the belief that the addition of 1 WAR equals a 1 win improvement.

Click here to read the full article on Beyond The Box Score.