TABLE 1.

Former research on gamification.

Author(s)	Domain	UH
Eisingerich et al., 2019	Customer engagement	N/A
Hamari and Koivisto, 2015	Gamification service
Harwood and Garry, 2015	Customer engagement
Hassan et al., 2019	Motivational feedback
Helmefalk and Marcusson, 2019	Servicescape context
Hsu and Chen, 2018	Marketing activities
Huotari and Hamari, 2012	Service marketing
Hwang and Choi, 2019	Loyalty programs
Jang et al., 2018	Mobile exercise application
Koivisto and Hamari, 2019	Motivational information systems
Kuo and Chuang, 2016	Online academic dissemination
Leclercq et al., 2018	Online co-creation communities
Liu et al., 2017	Information system
Liu et al., 2018	Smartphone-based job design
Morford et al., 2014	Behavior analysis and game design
Moro et al., 2019	Hotel online review’s traits
Pace and Dipace, 2015	Learning for tourist operators
Suh and Wagner, 2017	Knowledge contribution
Suh et al., 2017	Workplace
Suh et al., 2018	User engagement
Tobon et al., 2019	Online consumer decision
Toda et al., 2019	Educational-social networks
Wu and Seidmann, 2018	Business decision making
Xi and Hamari, 2019	Intrinsic need satisfaction
This research	Omnichannel	Yes

UH, Unobserved Heterogeneity.