Baseball statistics play an important role in evaluating a player's and/or team's progress. 

Since the flow of a baseball game has natural breaks to it, and normally players act individually rather than performing in clusters, the sport lends itself to easy record-keeping and statistics. Statistics have been kept for professional baseball since the creation of the National League and American League, now part of Major League Baseball. 

Many statistics are also available from outside of Major League Baseball, from leagues such as the National Association of Professional Base Ball Players and the Negro Leagues, although the consistency of whether these records were kept, of the standards with respect to which they were calculated, and of their accuracy varied. 

The practice of keeping records of player achievements was started in the 19th century by Henry Chadwick. Based on his experience with the sport of cricket, Chadwick devised the predecessors to modern-day statistics including batting average, runs scored, and runs allowed. 

Traditionally, statistics such as batting average (the number of hits divided by the number of at bats) and earned run average (the average number of earned runs allowed by a pitcher per nine innings) have dominated attention in the statistical world of baseball. However, the recent advent of sabermetrics has created statistics drawing from a greater breadth of player performance measures and playing field variables. Sabermetrics and comparative statistics attempt to provide an improved measure of a player's performance and contributions to his team from year to year, frequently against a statistical performance average.
Does that make it harder or easier for record keeping?
easy record-keeping