The new season of the J-League kicked off tonight, so for completeness’ sake I’m extending my analysis of club impacts on effective time in the J-League to its lower divisions. The analysis is similar to previous work with a slightly different way of presenting the results.
The effective match data was collected by DataStadium as part of an J-League initiative called Plus Quality, which attempts to assess and improve the quality of their on-field product, from increasing playing time to decreasing time lost due to negative events. Plus Quality started in 2013 and involves all league matches in the J-League’s three divisions as well as the League Cup competition.
Here are some summary statistics of effective playing time in J2 and J3:
- The mean effective playing time in J2 matches was 3110 seconds, or 51 minutes 50 seconds. In J3 the mean time is actually higher at 3228 seconds or 53 minutes 48 seconds.
- The standard deviation of effective playing time in J2 and J3 matches is 280.2 seconds and 257.1 seconds, respectively.
- The matches with most effective time in J2 and J3:
- J2: Shimizu S-Pulse vs Renofa Yamaguchi (65 minutes 15 seconds)
- J3: Blaublitz Akita vs FC Tokyo U-23s (64 minutes 0 seconds)
- The matches with least effective time in J2 and J3:
- J2: Ehime FC vs V-Varen Nagasaki (39 minutes 13 seconds)
- J3: Kagoshima United vs SC Sagamihara (43 minutes 21 seconds)
I’ve written previously on the details of the analysis which you can find at this post. I’m representing the results a little differently using a boxplot, which displays the median and quartile boundaries (the “box”) as well as the extremes of the distribution (the “whiskers”). In terms of Bayesian thinking, the box represents a 50% credible interval of club impact and the whiskers a 95% credible interval. (The mechanics of generating the plot take some time to get used to; first order of business is to create a plot of reasonable size!)
Below is the club impact on effective playing time in J2 2016. The only team that appears to have a positive impact on effective playing time is Shimizu S-Pulse, who on average account for four more minutes of playing time. To a lesser extent, Cerezo Osaka and Consadole Sapporo also make positive contributions to effective playing time. On the other side of the list, FC Machida Zelvia’s accounts for a reduction of playing time by more than five minutes, followed by Mito Hollyhock, FC Gifu, Thespa Kusatsu Gunma and Matusmoto Yamaga FC. Overall the presence of J2 teams in league matches doesn’t account for consistent shifts in effective time.
The club impact on effective playing time in J3 2016 is also below. Gamba Osaka U23 and Kataller Toyama have the most positive impacts on playing time, and Kagoshima United, Tochigi SC, and to a lesser extent Nagano Parceiro have the most negative impacts on playing time. Oita Trinita, who were promoted, appeared to have an impact on effective playing time that was positive but in about 15-20% of their matches the impact was negative.