I acquired all of the Division I team data since 2002, and from that we can observe some fascinating trends and data relationships in the data. This is a multipart series exploring some of that data.
In the last part of the series I highlighted overall shooting percentages of opponents across the last 23 seasons. That's a large statistic, and if we parse out its parts, we can learn more about what is really going on.
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 3-point field goal percentage allowed (3fg%) has essentially hovered in the 34%-35% range for the past 23 seasons, but has recently been pushed down a percent. As a reminder, in that period there were 2 big rule changes which pushed the line back: 1 foot beginning with the 2009 season, and 4 inches in 2020. After each of these rule changes we saw a dip of 1-2 percentage points on the offensive side of the ball.
When we look at tournament teams, we see a constant pattern, shadowing the national average about 1-1.5% lower.
UNC's 3FG% history has been erratic, with really great performances in the 2014 and 2015 years, and poor performances in the 2016-2018 seasons. The current team appears to be having one of the best seasons in the era as it pertains to guarding the 3.
This stat correlates with Winning Percentage with a -0.465 factor, so it is a nice stat, actually better than its offensive counterpart, for evaluating teams.
[h2]Percent Taken from 3[/h2]
One important aspect of shooting is how many shots are being taken behind the arc. From the graph we see that opponents were opting much more for 3-pointers annually until the 2019 rule change where the stat plateaued. Tournament teams' opponents used to not be enamored of the shot, but in the mid '10s analytics started showing coaches that they were getting more points per possession on possessions ending with a 3 point attempt than they were inside the arc, so we saw a big strategy change by the field's more savvy coaches.
One of the more surprising trends for UNC is the constant upswing of 3s taken against the program, proceeded by a precipitous drop since 2019. This season the Heels are seeing an average proportion of 3s taken by opponents.
We won't spend too much time pondering this stat, though, as it's correlation factor is a meager -0.065.
[h2]2-Point Field Goal Percentage[/h2]
We saw on the offensive side that 2-point field goals are the gold standard of all of the box score stats. On defense we see the same trait.
Looking at 2-point Field Goal Percentage (2FG%) allowed tells us more about the effectiveness of the big men on defense. From this graph we see a distinct rise over time of percentage allowed, with the national average rising a full 2 percentage points in the period. Perhaps more teams are taking 3s, pulling guards out of defensive positions in the lane. Perhaps the game is being officiated differently. Nevertheless, we also see a distinct echo by tournament teams of the national average, positioned about 2 percentage points lower.
UNC's performance here strongly follows the tournament average, with this team suppressing opponents by roughly 0.5% over the tournament average.
This stat has a correlation factor of -0.549, so it is one of the most important stats there is.
Next up: Effective Field Goal Percentage Allowed
In the last part of the series I highlighted overall shooting percentages of opponents across the last 23 seasons. That's a large statistic, and if we parse out its parts, we can learn more about what is really going on.
3-Point Field Goals
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 3-point field goal percentage allowed (3fg%) has essentially hovered in the 34%-35% range for the past 23 seasons, but has recently been pushed down a percent. As a reminder, in that period there were 2 big rule changes which pushed the line back: 1 foot beginning with the 2009 season, and 4 inches in 2020. After each of these rule changes we saw a dip of 1-2 percentage points on the offensive side of the ball.
When we look at tournament teams, we see a constant pattern, shadowing the national average about 1-1.5% lower.
UNC's 3FG% history has been erratic, with really great performances in the 2014 and 2015 years, and poor performances in the 2016-2018 seasons. The current team appears to be having one of the best seasons in the era as it pertains to guarding the 3.
This stat correlates with Winning Percentage with a -0.465 factor, so it is a nice stat, actually better than its offensive counterpart, for evaluating teams.
[h2]Percent Taken from 3[/h2]
One important aspect of shooting is how many shots are being taken behind the arc. From the graph we see that opponents were opting much more for 3-pointers annually until the 2019 rule change where the stat plateaued. Tournament teams' opponents used to not be enamored of the shot, but in the mid '10s analytics started showing coaches that they were getting more points per possession on possessions ending with a 3 point attempt than they were inside the arc, so we saw a big strategy change by the field's more savvy coaches.
One of the more surprising trends for UNC is the constant upswing of 3s taken against the program, proceeded by a precipitous drop since 2019. This season the Heels are seeing an average proportion of 3s taken by opponents.
We won't spend too much time pondering this stat, though, as it's correlation factor is a meager -0.065.
[h2]2-Point Field Goal Percentage[/h2]
We saw on the offensive side that 2-point field goals are the gold standard of all of the box score stats. On defense we see the same trait.
Looking at 2-point Field Goal Percentage (2FG%) allowed tells us more about the effectiveness of the big men on defense. From this graph we see a distinct rise over time of percentage allowed, with the national average rising a full 2 percentage points in the period. Perhaps more teams are taking 3s, pulling guards out of defensive positions in the lane. Perhaps the game is being officiated differently. Nevertheless, we also see a distinct echo by tournament teams of the national average, positioned about 2 percentage points lower.
UNC's performance here strongly follows the tournament average, with this team suppressing opponents by roughly 0.5% over the tournament average.
This stat has a correlation factor of -0.549, so it is one of the most important stats there is.
Next up: Effective Field Goal Percentage Allowed
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