# Analyzing Two Key Factors When Betting NCAA Basketball Totals

Ed Feng

Friday, February 26, 2016 4:59 PM UTC

Friday, Feb. 26, 2016 4:59 PM UTC

Why more college basketball games might go under? Let's work around 2 elements to consider before doing your NCAA basketball picks.To understand you must break it down into pace and efficiency.

How has the shorter shot clock affected college basketball?
College basketball shortened the shot clock from 35 to 30 seconds this season. As a result, teams have averaged 72.4 points per game, up from 66.9 last season.

How to calculate pace
The total points in a college basketball game depends on pace, or the number of possessions each team has in a game. The 30 second shot clock has increased pace. Let's put some numbers behind this.

To calculate pace, it's best to look at play by play data. However, this isn't available for all college basketball games. Instead, we attempt to estimate the number of possessions from the box score.

There are three ways a possession can end: a made shot, a missed shot with a defensive rebound and a turnover. The box score tracks turnovers, which makes it easy to count these possessions.

However, the box score doesn't tracked missed shots rebounded by the defense. To make an estimate, first consider shots from the field. You can convince yourself that the number of made shots and missed shots rebounded by the defense is total field goal attempts minus offensive rebounds.

We must also consider free throws. Every free throw came as a part of a two shot foul, we could simply estimate that half of free throw attempts end a possession.  Note that the offensive rebounds might come after a second free throw.

However, some free throws happen has part of a three point play or the front end of a one and one. These attempts can also end a possession.

In the end, I use this popular formula to estimate pace from the box score:

(number of possessions) = (shots attempted) - (offensive rebounds) + 0.475 (free throw attempts)

This season, college basketball teams have averaged 69.9 possessions per game, up from 65.6 last year. The almost four and a half more possessions a game has an obvious affect on scoring.

This estimate of pace is most likely on the high side. Offensive rebounding is down in college basketball this year (29.9% of rebounds go to the offense compared with 31.1% last year). Fewer offensive rebounds means that teams are not extending possessions by rebounding their own shots, which leads to more possessions overall.

However, there's no reason like some rule change for the decrease in offensive rebounds. Offensive rebounds should increase due to regression to the mean. This implies that pace should decrease towards the end of the college basketball season.

Efficiency
Pace is only part of the scoring equation. We must also consider the efficiency at which teams score, and this is measured by points per possession.

This season, teams have scored 103.5 points per 100 possessions, up from 102.0 last year. I can identify two reasons for this increase, and one of them is unlikely to persist.

First, college basketball teams continue to shoot more three pointers. This season, 35.3% of field goal attempts have come from behind the arc. This is an increase over the 34.2% rate from last season and the historical average over the past decade of about 33%.

This higher rate of three point shots increases efficiency. Based on college basketball averages, a three point shot averages 104.1 points per 100 possessions, while two point shots net 97.2 points per 100 possessions. Teams have control over shot selection, so I expect this increased efficiency from 3 point shots to persist.

A second factor also plays a role in the increased efficiency. Teams have shot 48.6% on two pointers this season, up from 47.7% last season. There's no rule change or other reason to expect a change in this number, so regression in field goal percentage on two point shots should lead to less efficiency.

Outlook
If you look at college basketball totals, you must consider the increased pace and offensive efficiency this season in making a number for each game. The above analysis suggests that both of these numbers should decrease slightly for the rest of the season.

Also, note that the increased pace affects slow teams more than fast teams. A team like Virginia uses most of the shot clock on each possession, and the lack of an extra five seconds makes a difference. On the other hand, North Carolina likes to get up and down the floor, so the shot clock doesn't affect them as much.

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