What does the Memphis Grizzlies' winning streak without guard Ja Morant say about Morant and the nature of on/off statistics?
This week's lead mailbag question asks what we should take from the Grizzlies' performance without Morant, who has missed the last three weeks with a knee sprain. During that span, Memphis has gone 9-1, including a victory over the Oklahoma City Thunder by the largest winning margin in NBA history.
Answering that question also helps us understand how volatile on/off statistics, or in this case splits of performance without a player in the lineup entirely, can be over small sample sizes -- a cautionary tale worth remembering for future situations.
Throughout the NBA season, I answer your questions about the latest, most interesting topics in basketball. You can tweet me directly at @kpelton, tweet your questions using the hashtag #peltonmailbag or email them to peltonmailbag@gmail.com.
This week's mailbag also addresses questions on the Dallas Mavericks' high-volume 3-point shooters regressing to the mean and on the accuracy of the multiplier we use to estimate possessions based on free throw attempts.
"I can't believe the Grizzlies are doing so well without Morant. Do you think they are better off without him and if so what should they look for if they trade him?" -- Kirby
This question has a short answer and a long answer. The short answer is no, Memphis is not better off without Morant and absolutely should not look to trade one of the NBA's brightest young stars before he even reaches restricted free agency.
The long answer is that Morant is yet the latest example in a long, long line showing that net rating differential -- something the statistical analysis community, myself included, admittedly popularized -- is dangerously flawed because of the role of shooting randomness over small samples.