From SABR member Jonathan Luman at The Hardball Times on November 4, 2015, with mention of SABR member Jon Roegele:
Early in September, Jon Roegele pointed out that scoring in August was way up, countering a longstanding downward trend. My first thought was, “Hooey! This is no more than the result of random variation.” This idea is supported by observing that the monthly scoring rates were roughly normally distributed and that the August value was two standard deviations above the mean, as you can see in Figure 1. The August scoring rate was high, but a normal distribution predicts there will be some extreme values like this.
Stated another way, assuming that the run environment had changed in August appeared to me to be the base rate fallacy. The base rate fallacy can occur when an unlikely explanation (August scoring was high due to random sampling, P ≈ 0.02) is dismissed, even though the alternative (an increase in the run environment, P = unknown, presumed to be << 0.02) is even less likely.
But then scoring in September was just as high as it was in August. The likelihood of consecutive months sampling at extreme values is very low if due to randomness alone (P ≈ 0.02*0.02). This suggests a more causal variable was introduced into August and September. So, my second thought was that the August and September average scoring rate was elevated by a rash of high-scoring games. If this were the case, it would be observable in the distribution of game scores (i.e., the actual tally of runs).
Read the full article here: http://www.hardballtimes.com/are-high-scoring-games-making-a-comeback/
Originally published: November 4, 2015. Last Updated: November 4, 2015.