NBA talent dilution/concentration
- A couple of weeks back, in the APBR room, a comment I made about
the year 1977, (with the ABA merger, perhaps talent concentration
reached a peak then) evolved into an analysis of players who played
both in '76 and '77, and how their numbers changed in that one year.
Eventually, it was noticed that the 189 players' minutes in '77
were only 87% of their '76 minutes, on average. It was even
suggested that talent was on average 11.5% greater; though I don't
think this is necessarily a quantitative fact, I think it has to say
So I finally got around to checking every season of the NBA, since
1952 (before which, minutes are not recorded), and have some
A complete table would look something like this:
counted avg. min. conc. cum.
year plrs. prev. this fac. conc.
1953 59 1777 1928 .921 .921
1954 56 1981 1928 1.028 .947
1955 51 2080 1910 1.089 1.031
1956 58 1944 1817 1.070 1.103
...and so on.
So in 1956, there were 58 players who also had played in 1955.
Their average minutes dropped from 1944 to 1817, so the
league "talent concentration factor" for 1956 is estimated by
1944/1817 = 1.070.
Boldly, I multiply each year's factor to get the "cumulative
concentration factor". Now, of course, we know that small errors or
systematic flaws can become exponentially exaggerated when one is
multiplying them many times. Still, one may infer that "something"
is implied when certain results are consistent.
As it turns out, there are very few years in NBA history when
talent seems to have diminished, by this measure. Certainly
expansion years are evident, as counter to the trend, but only 12 of
44 seasons (1953-'96) indicate dilution of talent. The average of
those 44 years is 1.046 concentration factor, and the cumulative
factor is over 2.5.
I am not stressing the accuracy of a 44-year factor, but I would
be willing to assert that the "watering down of talent due to
expansion" is basically a myth.
As I worked through these years, I fully expected to see this
dilution creep in. But through 1996, it never does appear. I did
stop at 1996, as I have some accounting methods which changed then,
but I will be straightening that out shortly, as well as going back
and separating NBA players from ABA, in those years.
Meanwhile, I would love to see alternative interpretations of
league-wide reduction of minutes played, per player.