I acquired all of the Division I team data since 2002, and from that we can observe trends and data relationships in the data. This is a multipart series exploring some of the most interesting facets of that data.
Wrapping up the discussion of field goal shooting, we'll tackle Effective Field Goal Percentage (eFG%). This stat weighs 3-point shooting so that the value of the shot is considered in the percentage. The calculation for this stat is:
FGMs and FGAs includes 3-pointers, but we add in 50% more for the 3FGM's since that is how they are scored. The problem with this equation is that it is possible to get a result higher than 100%. Nevertheless, it still is more popular these days than overall field goal percentage in measuring a team's potency from shooting.
The graph shows the national average in grey, the average for NCAA Tournament teams in green, and UNC's average in blue.
From this we see that national eFG% has essentially hovered in the 50% range for the past 23 seasons, with a slight elevation in 2016. The standard deviation is 3 percentage points, so we see a wide variation among college basketball in this stat.
When we look at tournament teams, we see a much more erratic pattern, just as we saw with 3-point shooting in Part 4. Tournament teams did not follow the national average very closely at all up to 2015. It appears, though, that tournament teams have settled into having eFG percentages that are roughly 2.0 percentage points higher than the national average.
UNC's eFG% history has been erratic, mainly from its erratic 3-point shooting history. The current team, at 51.5%, appears to be exceeding the national average (51.0%) by two hairs, but likely trails the anticipated tournament level by probably 1.5 percentage points.
How useful is Effective Field Goal Percentage? It correlates with Winning Percentage more than most stats. On a scale of 0.0 to 1.0, it has a 0.602 correlation factor. Given its attempt to properly include 3-point shooting, however, eFG actually has a lower correlation with Winning Percentage than plain old Field Goal Percentage. FG% is the king of all commonly discussed stats with a factor of 0.625. The reason eFG% is worse is that is that 3-point shooting percentage has a correlation factor of only 0.421. The extra weight of this mediocre stat is leading to unwarranted emphasis of eFG% in the basketball world. Stick with plain old FG%.
Next up: Free Throw Percentage
Wrapping up the discussion of field goal shooting, we'll tackle Effective Field Goal Percentage (eFG%). This stat weighs 3-point shooting so that the value of the shot is considered in the percentage. The calculation for this stat is:
eFG% = (FGM + (0.5 * 3FGM)) / FGAFGMs and FGAs includes 3-pointers, but we add in 50% more for the 3FGM's since that is how they are scored. The problem with this equation is that it is possible to get a result higher than 100%. Nevertheless, it still is more popular these days than overall field goal percentage in measuring a team's potency from shooting.
The graph shows the national average in grey, the average for NCAA Tournament teams in green, and UNC's average in blue.
From this we see that national eFG% has essentially hovered in the 50% range for the past 23 seasons, with a slight elevation in 2016. The standard deviation is 3 percentage points, so we see a wide variation among college basketball in this stat.
When we look at tournament teams, we see a much more erratic pattern, just as we saw with 3-point shooting in Part 4. Tournament teams did not follow the national average very closely at all up to 2015. It appears, though, that tournament teams have settled into having eFG percentages that are roughly 2.0 percentage points higher than the national average.
UNC's eFG% history has been erratic, mainly from its erratic 3-point shooting history. The current team, at 51.5%, appears to be exceeding the national average (51.0%) by two hairs, but likely trails the anticipated tournament level by probably 1.5 percentage points.
How useful is Effective Field Goal Percentage? It correlates with Winning Percentage more than most stats. On a scale of 0.0 to 1.0, it has a 0.602 correlation factor. Given its attempt to properly include 3-point shooting, however, eFG actually has a lower correlation with Winning Percentage than plain old Field Goal Percentage. FG% is the king of all commonly discussed stats with a factor of 0.625. The reason eFG% is worse is that is that 3-point shooting percentage has a correlation factor of only 0.421. The extra weight of this mediocre stat is leading to unwarranted emphasis of eFG% in the basketball world. Stick with plain old FG%.
Next up: Free Throw Percentage
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