Separating the Impact of Pitching and Fielding
The easiest way to judge the effectiveness of pitching is to isolate those things that don't involve fielders: Strikeouts, Walks and Home Runs. That's what FIP ((HRA*13+BB*3-K*2)/IP+3.10) measures.
All other batting events are batted balls that involve fielders. To measure what happens on those balls, we use Defense Efficiency Ratio (DER), which is simply the percent of batted balls (not including home runs) turned into outs by fielders. DER reflects a lot of complex stuff, such the quality of the fielders, the gloves, the ballpark configurations, how hard the ball was hit, where it was hit, and probably a few more things I haven't thought of. So it isn't a perfect measure of fielding excellence but it's not bad and it's easy to calculate.
The best teams at turning batted balls into outs are on the top and the FIP axis (on the bottom) is reversed so that the best pitching teams are on the right.