This baseball statistic, which depends on the decision of the official scorer, refers to when a runner advances a base on a pitch but is not given credit for a stolen base because the opposing team made no attempt to hold him at the previous base, and no attempt was made at the base he advanced to. This typically occurs late in games when the runner represents a run that does not matter to the outcome of the game.
A defensive indifference scoring is at the sole discretion of the official scorer at each ballpark, and it is normally seen in the ninth inning when a game is out of hand. Typically, the team trailing and having a man on first base will advance the runner to second to avoid a force play or double play to end the game. It makes the defense work a little harder, depending on where the ball is hit. However, this ruling is occasionally seen in games as close as two runs. For example, let's say a team is down by two runs in the final inning and has a man on first with two outs. It makes sense to advance the man to second base to eliminate a simple force play ending the game. The defensive team will let him take second base because his run means nothing, since it is the batter who is the tying run.