TABLE 1.

Description of expertise criteria in LOL studies.

Study	Groups of participants	Expertise criteria
Chang et al. (2017)	MOBA players (n = 30). Players who reported only play LOL (n = 27). Non-online players (n = 58)	Players and non-players were classified based on The Internet Usage Questionnaire. Groups were formed based on the response of the following questions: Do you play any online game with interaction with other players? How many hours do you spend on playing such online game? Do you play any online game with single operation? How many hours? In the past year, how much time did you spend on internet a week?
Ding et al. (2018)	Professional players (n = 10) Semiprofessional players (n = 10) Casual players (n = 20)	LOL Secondary professional league Amateurs from a summer training camp. They shown potentials in LOL and might eventually become professional players. Casual players who self-reported playing the game frequently. 70% were classified in the in-game ranking.
Qiu et al. (2018)	Action video game experts (n = 15) Action video game non-experts (n = 14)	Two years of experience in action video games and expertise based on rank classification (percentile 93%) Less than 0.5 years of experience in action video games and rank classification between 29.92 and 45.11%.
Li et al. (2020)	Experts players (n = 35) Average players (n = 35)	Players ranked higher than Diamond tier (percentile 99.8%) Players ranked between Iron and Diamond tier
Yao et al. (2020)	Experts players (n = 18) Non-experts players (n = 19)	Two years of experience in action video games and expertise based on rank classification (percentile 93%) Less than 0.5 years of experience in action video games and rank classification between 29.92 and 45.11%.

LOL, League of Legends; MOBA, Multiple Online Battle Arena.