In light of Ben’s post where Hollinger is quoted,
Nobody talks about the Blazers as serious contenders in the West, but we should. Portland had the best scoring margin in basketball after the All-Star break last season, and as I keep repeating, scoring margin predicts future success better than winning percentage.
I’d like to take a look at what that statement signifies.
The only research I’ve ever done which is basketball related, is the direct correlation of scoring margin (Point Differential) to win %. That relationship could not possibly be more of a direct one to one relationship.
14 years of NBA data (all teams included) show that a team with a point difference of "0" (i.e. scoring margin) crosses the line at approximately 40.95 wins. Frankly, I personally don’t see how you could get any closer to a direct correlation unless this data resulted in exactly 41 wins (a .500 season),to which it almost did.
Here’s a chart of those 14 years. Number of wins at the top and point differential at the left.
If I have evaluated the data correctly the largest deviation from this straight line at any win% level (listed as number of games won in this chart) is +2.9 points to the high side and –2.6 to the low side. This is an extremely significant number, in 14 years not one team has deviated more than 3 points from this median. If you didn’t know a teams scoring margin, by choosing the median if given the number of wins you could tell within 3 points what their scoring margin was.
In my mind that declaration (quote above from Hollinger) can only be interpreted one way.
What Hollinger’s statement suggests (even though scoring margin is a direct correlation to win%) is that scoring margin leads win% for a team on the rise, or stated in other words, win% lags scoring margin. So a team who continually does better in scoring margin than what they actually achieve in win%, should be a team on the rise.
It therefore also means that this must true for a team that is in decline. So a team declining from prominence will have a better win% than what their point diff would suggest.
To restate this, hopefully a little better, If scoring margin is a better indicator of future success, then a team on the way down should have a point differential which is a little worse than their record (win%).
So if Hollinger be correct, point differential leads the way, whether that team is going up or going down.
Scoring margin is a little better than win% if going up, a little worse if going down.
Is this true, I don’t know? But before San Antonio upgraded most would agree they were a team in decline and they had point diff of 3.8 last year which should have resulted in about 49-50 wins and they had 54 wins. So in SA’s case, scoring margin was leading the way down. So with a sample size of 2, Blazers and San Antonio, it is true.
Update: I hate when I have a moment of clarity long after posting.
Bottom line is this: 54 wins means absolutely nothing. going from 41 to 54 means nothing. It does not tell you anything about how many wins will be added next year. You can’t add 13 to 54 and get 67. The more pertinent question is, did I have a point difference of 3.0 or 9.0 when I got those 54 wins. Take two teams with 54 wins, one with each of the afore mentioned scoring margins, and I’ll tell you who’s going to beat who in the near term. (this was my take on Hollinger when putting up the post, I hope it came thru)
What does this mean for the Blazers next year?
Here is a table of the Season, which lists how many games we won for the season, and how many were won for the last 41 & 21 games of the year. It also is a projection of how many games the Blazers would have won if the last 41 & 21 games were extrapolated out to 82 games. There is a projection based on win% so it can be compared to how many games we should have won if based on scoring margin.
The very bottom line is a projection of how many games we should have won if based on scoring margin.
This table shows that scoring margin is leading win%.
I removed 54 games from the table because it was not a projection. Our point diff of 5.34 suggested a 56 win season, 2 games better than the 54 we won. Notice the last 2 lines where this spread widens as the season continues.
In the last 41 games our actual win% would yield 58 games but point diff suggested 4 to 5 games higher at 62-63 wins.
And then the last 21 games win% = 62-63 (62.48), but point diff proposes 68-69 (68.8), spread widens to 6+.
So scoring margin kept leading by a larger spread. See last paragraph where the last 21 games was not a weaker schedule than the last 41 games.
The same information can be interpreted from the chart below.
The Blazers had a point diff of 9.8 for the last 21 games, which on the chart below shows a 68 win season actually about 68.8. Compared to a win % which would have yielded about 62 wins. All things being equal a 62 win season should have around a 7.4 scoring margin. We were 2.4 points above this level for those last 21 games.
Their last 41 games had a diff of 7.7 which yields about 62 wins (this is eyeballed from chart, table shows 62.48).
Compared to 58 wins if based on a .707 win%. Likewise a 58 win season should yield about a 6.0 margin, but we had 7.7 which is 1.7 better for the last 41 games.
So point differential is leading win% in both of the later segments.
The point diff for the first 41 games was 2.91, which would be in terms of games won, a 49 win season. So the Blazers scoring margin went from lagging win% in the start of the year to leading win% by the end of the year.
(Please note: the way to view this chart is to come across horizontally from any point diff level, when that line hits the median line then draw a vertical line upwards to see projected wins. Since this chart has wins at the top instead of win%, I included in the table above the number of games won based on the win% - see projected games won based on win%)
One way to look at the chart above and probably the best way, is to note that a point differential above the median line is leading win% rather than lagging it. Which is how the Blazers ended the season. Scoring margin leading win%.
Only 3 teams in the last 15 years had a scoring margin above 9.8 and all 3 were NBA Champs (Blazers were at 9.8 for last 21 games). (charts above were based on 14 years due to a shortened season)
If Hollinger is anywhere close to being accurate 60+ wins is close to being in the bag. The only caveat that I did not discuss in this post is how far wins can deviate from point diff. Looking at the chart this appears to have a range of about 20 games wide across the median. i.e. +/- 10 games. But in reality the widest range I could find was about 14 games at the widest point (using increments of .1 for point diff), which yields a +/- of about 7 games. What this means is we could be above or below by 7 games and still be within normal. Taking the worst possible scenario still yields a win of 61 games if the last 21 games are chosen to conjecture upon. If the last 41 games is chosen a worst case senario is somewhere near 56 games.
But then again in this worst-case scenario, win% would be lagging point differential by the widest of margins. So if it were possible to take the end of last year and project it onto this year, 56 wins is our floor. Any way you look at it, things are looking good.
One Final note:
In the table above, if point differential were to lead win% by the same margin next year as in the last 21 to 41 games of this past year. And if in next year all teams were the same. Then the table would be fairly accurate with a range of 58 to 62 wins. The win% of the 1st 41 games of our opponents was .507, the win% of opponents in the last 41 games was .480, the last 21 games .496
How much 4 rookies with a year under their belt, Andre Miller, a healthy Oden & Martell, and a slashing Nic counteracts a weaker 2nd half schedule is anybodies guess.
We’ll have to play the games to find out.