2017-18 quick observations

[Crow]

Westbrook this season adds value as a threat, an assist man and as a free throw shooter (most of the time) but as a shooter he is a liability. At over 24 shots per game in last 10, he has shot worse than his terrible season level mark. 5-21 so far tonight will push the efg% even lower.

[Crow]

After tonight's loss, the Celtics point margin falls to plus 0.2 pts per game for last 10 games (I think). 6-4. Their defensive rating over this span is probably real near average, perhaps just above.

[shadow]

According to my relatively basic power ratings, home court advantage has only been worth about 1.8 points per game so far this season. Last year it was worth about 3 points per game in the regular season according to both my personal ratings and the Sagarin ratings.

https://web.archive.org/web/20170413212 ... 17/rating/

[eminence]

According to my relatively basic power ratings, home court advantage has only been worth about 1.8 points per game so far this season. Last year it was worth about 3 points per game in the regular season according to both my personal ratings and the Sagarin ratings.

https://web.archive.org/web/20170413212 ... 17/rating/

Interesting... Any ideas on cause?

[Crow]

Less friendly fouls called for home stars? That is just a possible answer. I haven't analyzed.

[shadow]

There probably haven't been enough games played yet this season to say if that decline is statistically significant. An ESPN article from a couple years ago had some theories though on why HCA might be declining:

http://www.espn.com/nba/story/_/id/1224 ... ge-decline

Theory 1: The NBA is more 3-point heavy, less dependent on referees
Theory 2: Technology has allowed teams to handle the road better
Theory 3: Home crowds are no longer the sixth man

[Mike G]

Sagarin says HCA is 2.45 pts.
https://www.usatoday.com/sports/nba/sagarin/

[shadow]

I think his ratings still utilize preseason ratings at this point in the season. For instance, GS & HOU are virtually tied in B-R's SRS right now (10.76 vs 10.70), whereas GS has a 2.26 point lead over HOU in Sagarin's predictor rating, which usually correlates almost perfectly with SRS at the end of the season, presumably when preseason ratings have been completely dropped. I think the only way GS could have that type of lead in a power rating is if preseason ratings are still having some influence. If he's still using a preseason prior for individual teams he's probably also using one for HCA.

If you take the difference between the average points scored per game by home teams versus away teams this year as a simple method of calculating HCA, you get 1.90, which is very close to the 1.82 value my ratings are showing right now. HCA will probably rebound to around 2.5 points per game before long, which will make this discussion mostly moot anyway. I just found it mildly interesting it was that low when around 36% of the regular season games have been played.

[Mike G]

Some usual suspects show bigger HCA so far this year.

Code: Select all

HCA  West  HMOV  AMOV      HCA  East  HMOV  AMOV
7.5   Den   8.6  -6.4      8.4   NYK   6.9  -9.9
6.5   Uta   8.9  -4.1      4.3   Tor  13.4   4.8
4.3   SAS   6.9  -1.7      3.0   Cha   0.5  -5.4
4.2   Dal   0.5  -7.8      2.6   Phl   2.2  -3.0
4.1   OKC   6.1  -2.0      2.5   Chi  -5.0 -10.0
3.4   Sac  -5.6 -12.3      1.8   Det   2.9  -0.7
3.1   LAC   1.2  -5.0      1.5   Was   3.8   0.8
2.3   LAL  -0.6  -5.3      1.3   Brk  -2.4  -4.9
2.1   Min   3.2  -1.0      1.2   Bos   6.7   4.3
1.2   NOP   0.3  -2.0      0.7   Mil   0.2  -1.2
0.8   Mem  -3.6  -5.1      0.3   Atl  -5.3  -5.8
0.6   GSW  11.8  10.6     -0.2   Ind   1.2   1.6
-1.1  Phx  -8.6  -6.3     -0.8   Orl  -5.1  -3.4
-1.2  Hou   9.8  12.2     -2.3   Mia  -4.4   0.2
-2.4  Por  -0.1   4.6     -2.6   Cle   1.7   6.9
2.3   avg   2.6  -2.1      1.4   avg   1.2  -1.7

Avg of all teams is 1.89
It is possible that the weaker teams have played more home games, or some such thing.

[shadow]

If you wanted to calculate it for an individual team I think it would be:

HCA = (HomeMOV - AwayMOV) / 2

However, individual team HCA values tend to be quite noisy and it's usually just calculated league wide as one variable in most power ratings.

[tarrazu]

There probably haven't been enough games played yet this season to say if that decline is statistically significant. An ESPN article from a couple years ago had some theories though on why HCA might be declining:

http://www.espn.com/nba/story/_/id/1224 ... ge-decline

Theory 1: The NBA is more 3-point heavy, less dependent on referees
Theory 2: Technology has allowed teams to handle the road better
Theory 3: Home crowds are no longer the sixth man

To go with Theory 1, free throw rate is down 1.5% right now, from 27.1% to 25.6% (per bref: https://www.basketball-reference.com/le ... _stats::13). Fouls are one of the reason for home court advantage (dependent on a ref to call a foul), so less fouls is less disparity in scoring from the FT line.

[shadow]

Related evidence for theory 1: 3 point attempt rate is up 2.2% right now compared to last year.

[Mike G]

So, what teams are shooting more 3's on the road, while attacking the rim at home?

[Crow]

Ingram "rounding into form"? Maybe physically. Hot from 3 point range. But RPM estimate still has him at close to -3 impact and 80th place for SFs.

[Crow]

Max contract awardee Andrew Wiggins: Lowest ts% of career and it has fallen further in last 10 games. Lowest rating on PER, WS/48 and BPM of career. RPM up a whopping 0.2 to -1.37.