RealGM

Website: http://mathofdefense.tumblr.com
Twitter: http://twitter.com/MathOfDefense

Let me be upfront about advanced basketball statistics in general: I've never been a huge fan of them. Watching the games live - the challenging of shots, the extra possessions, the botched passes, the benefits of pure heart and hustle - is way different from, and in my personal opinion, more gratifying than to hypothesize a team's defensive numbers based on equations and algorithms which involve exclusively existing tangible data from a box score. Don't get me wrong, I love math and numbers as much as the next statician, but sometimes, there are numbers in basketball that are ignored and underappreciated.

When I think of basketball defense, I ask myself these questions:

1. When you're contesting a shot to force a miss, or absorbing a charge to negate a basket, aren't you preventing points for the opposing team?

2. When you're stripping or spiking the ball away from the ball handler before a shot attempt or pass could be made, or when you're grabbing an offensive rebound after a missed shot to make the defense expend more of their energy, aren't you preventing a possession for the opposing team?

3. When you're intercepting a pass or tricking the ball handler into tossing the ball out-of-bounds, aren't you preventing an assist tally?

Any time you are playing defense, you are taking on a creed: "Prevent your opponent from doing any further damage to your game plan." This is Preventions, a metric which looks at defensive intangibles to confirm our beliefs of a team or an individual. The "eye indicator to the eye test," if you will.

Preventions is a highly involved process in which the source material is reviewed from beginning to end. All acts of contested shots, blocks, steals, charges, offensive rebounds, violations, and even out-of-bound deflections and jump balls are analyzed and accounted for in two separate game logs, one for each participating team. The findings are placed into a comprehensive chart filled with categories beyond your wildest mathematical imaginations and are published to my personal Tumblr account. These findings may be referenced to compare with and contrast against existing advanced basketball metrics.

Since 2013 when I conceived Preventions, I have always wondered if it may one day become the determinate defensive metric. My project has seen many trials and errors which have contributed to numerous revisions over the years. I've learned that even steals can prevent shot attempts. I saw how setting a simple screen or making the extra pass (hockey assist) prevents a turnover opportunity for the opposing team. I've accepted that not all events can be accomplished through one person, so I've taken the opportunity to credit those teammates willing to ensure the player's primary assignment is fulfilled or at the very least well guarded.

It is not easy being a one-man band. Every game I work on takes a toll of energy. I hope that one day, people who appreciate my metric will assist me so that I can cover for all teams, and not just the Clippers as you will see in my Tumblr account.

Please give me your thoughts on Preventions. I am well aware that I have not defined my standards for how I hand credits. I do plan on making a Preventions Bible in the future, but due to other projects I am working on such as my Wammy Radio podcast and a fan game unrelated to basketball, it will be very hard for me to accomplish this task. Rest assured that even if the Preventions Bible never comes to fruition, at least the ongoing logs and charts will be on schedule... even if I am a few games behind.

i don't see mention of defensive rebounds.. which are the MAIN way you terminate the other team's possession. a Steal.. of course changes possession. a Block..... is a maybe. it can disrupt but NOT terminate anything.
Then the flip side is extending or maximizing one's OWN posessions. obviously.. that's where offensive boards,minimizing TO's, offensive fouls will matter.

then... the BIG rule is that the team with the most POINTS on the board ALWAYS wins. WORK as a team.. can mean set picks, pass, just execute. Of course... you STILL need to make the basket.

old rem wrote:i don't see mention of defensive rebounds... which are the MAIN way you terminate the other team's possession.

I used to log defensive rebounds when I started Preventions for the 2013-14 season, but as I got more into the intricacies of defense, I learned that merely collecting the rebound is not enough. To truly terminate the other team's possession, you must carry your defensive rebound past the half-court line. As long as the ball is still behind the half-court line, your team is in danger of triggering a back court violation. Not to mention, the offensive team could attempt a last ditch effort to regain possession. This is one of the reasons why the SAVE and ERROR credits were created.

Here's how it works: if the defender completes an assignment, but fails to get the ball past the half-court line on account of a self-inflicted turnover (traveling, double-dribble, out-of-bounds fumble) or a forced turnover (steal, offensive foul), the credit achieved by the defender is placed into the Discredits section. The player who committed the turnover gets dinged with an ERROR on the main log. In the case of a forced turnover, the player who got possession back gets credited with a SAVE.

old rem wrote:a Steal.. of course changes possession. a Block..... is a maybe. it can disrupt but NOT terminate anything.
Then the flip side is extending or maximizing one's OWN posessions. obviously.. that's where offensive boards,minimizing TO's, offensive fouls will matter.

You're right about steals and blocks. In fact, there is a variation of the block called the Shot Block Delay, which is listed in my logs as 1 DELAY - BLK. Those are the blocks where there was no change of possession. If you see a point value attached to it, then there was a change of possession. But like I said above in my first paragraph, these things can be discredited if the defensive rebound is turned over for whatever reason. Any self-made mistake by the defense or recovery by the previous offensive team is logged accordingly.