One of the major questions around the increasing use of defensive shifts is whether they can help teams reduce the incidence of hits on balls in play, especially line drives and other "well-hit" balls in play that are more likely to become hits. (Line drives fall in for hits at roughly three times the rates of ground balls and fly balls, although the exact rates fluctuate each year.) Improving your defense by acquiring or developing better fielders can affect a team's batting average allowed on balls in play (BABIP). But we have anecdotal evidence from the last few years that heavy use of defensive shifts and/or improved defensive positioning can do so as well.