Table 1.

Previous works on gamification.

Previous works	Key characteristics
[12]	It classifies the gamification approaches into the following: focusing on the technological aspects of computer games, focusing on the behavior evoked by computer games, and focusing on the design of computer games. It provides some case studies which show the process and benefits of gamification
[13]	It describes the characteristics of generation Y and the key elements of games that deserve a place in the enterprise including performance, achievement, and social interaction
[14]	It shows the interaction matrix of basic human desires and game mechanics including points, levels, challenges, virtual goods, leaderboards, and gifting. It provides the recent cases of gamification such as the frequent flyer programs, Foursquare, and Nike Plus
[15]	It describes the concept, benefits, key elements and mechanics of game design, and various cases of gamification
[3]	It shows the patterns of user activity in an enterprise social network service after the removal of game elements. It proved that the removal of game elements reduced overall participation within the SNS
[16]	It provides an experiment in computer science class which provides more frequent commits using a social software application. This study shows that the game elements are effective to motivate engineering students
[17]	It provides examples of social games which show behavioral economic biases related to the loss aversion tendency which is one of the key factors of behavioral economics and prospect theory
[19]	It provides the classification of engineering students based on the Bartle's game player types using the online survey which consists of 24 questionnaires