As promised, I have gone through the NASL records and obtained
the following data regarding sudden-death overtime:
The NASL used 15 minutes of SD OT in all tied games from 1975
till the league's demise in 1984. Of the 546 regular season
games that were tied after 90 minutes, 251 were settled in SD OT.
That's about 46%
During that same period, NASL scoring averaged 3.46 goals per 90
minutes, and at that rate one would have expected about 44% of
the games to end during the 15 minutes of SD OT (if you wonder
where 44% comes from, see appendix below).
Hence, there is no evidence to support the idea that there was
less scoring during NASL SD OT, than in regulation play.
Looking at the NASL playoffs, where presumably teams would have
been even more cautious in SD OT, you find that half of the 28
tied games were settled in OT. That's better than the 42%
predicted by the 3.31 goals per 90 minutes playoff scoring rate.
Again, no evidence that SD OT leads to less scoring.
I only have slightly more than a years worth of APSL SD OT stats,
but they tell the same story.
Any other leagues where SD OT has been used? What about the J-
APPENDIX - Probability of a goal being scored during SD OT.
The magic formula is (I'm such a geek):
P = 1 - EXP(-R*T)
P = probability (or expected percentage of games)
R = Average rate of goal scoring per *minute*
T = Maximum duration of SD OT in minutes (eg 15 or 30)
EXP() = standard exponential function ("e" to the power "x")
It is derived by integrating the Gamma function associated with a
Poisson process over the appropriate time interval. Bet you're
sorry you asked, eh?
\ VANCOUVER 86ERS 7 Yrs, 11 Trophies
Alan Douglas \ Probability estimate that 86ers