Table 4.

Correlation matrix between gamification principles across all rated apps.

Gamification principle	Meaningful purpose	Meaningful choice	Supporting player archetypes	Feedback	Visibility
Meaningful purpose	N/Aa	0.71	0.50	0.48	0.30
Meaningful choice	N/A	N/A	0.69	0.11	0.11
Supporting player archetypes	N/A	N/A	N/A	0.57	0.57
Feedback	N/A	N/A	N/A	N/A	0.92
Visibility	N/A	N/A	N/A	N/A	N/A

^aN/A: not applicable.