When it comes to evaluating hitters, many baseball fans are doing it wrong. Most people use stats such as batting average, RBIs, or OPS. However, the best stat for evaluating hitters is none of these. The best stat to evaluate hitters with is wRC+.
The wRC+ stat is an extension of one of the first sabermetrical offensive stats, wRC. The reason wRC+ is better than wRC is that wRC+ is adjusted in accordance with the ballpark a player is playing in. This is one of the reasons why wRC+ is such a great stat, because a player who produces huge offensive numbers at Petco Park will be rated higher than one who does it at hitter friendly parks such as Coors Field or Great American Ballpark.