Table 2.

Variables constructed and coefficient alpha.

Variable	Year	Alpha (α)	N	Content
Creativity	Y1	0.878	5	① I can figure out things that many friends cannot; ② I can think of things that can be helpful in solving new problems; ③ I can imagine the whole content even if I only hear only a part of it; ④ I can make things connected each other even though they appear unrelated; ⑤ I can find many new ideas in a short time
	Y2	0.893
	Y3	0.898
	Y4	0.900
	Y5	0.912
Management	Y1	0.773	4	① I plan things before undertaking whenever I have plenty to do; ② I do not procrastinate on what I need to do today; ③ I check my planner/notice book and do not miss things that I need to do today; ④ I organize and clean my desk by myself; ⑤ I myself prepare/bring out things for school to work.
	Y2	0.762
	Y3	0.754
	Y4	0.765
	Y5	0.773
Peer-attach	Y1	0.914	6	Friendship relationship - peer attachment: ① My friends respect my thoughts when talking with me; ② My friends listen to what I say; ③ I tell my friends about my worries and problems; ④My friends understand me well; ⑤ I can tell my friends when I want to confide in my heart; ⑥ I trust my friends.
	Y2	0.909
	Y3	0.917
	Y4	0.929
	Y5	0.930
P_Ac_sup	Y1	0.806	6	① Parents create an environment for study at home; ② Parents check school studies and homework; ③ Parents give advice on my study; ④ Parents participate in my grade management; ⑤ Parents collect information to determine tutoring or private institutes; ⑥ Parents check my daily work/routine and manage my schedule.
	Y2	0.802
	Y3	0.867
	Y4	0.867
	Y5	0.861
P_Interaction	Y1	0.786	4	① My parents are concerned about me and ask questions regarding my school life; ② They respond to my questions kindly no matter how tedious they are; ③ They play games with me; ④ They read books together and talk.
	Y2	0.803
	Y3	0.840
	Y4	0.834
	Y5	0.833
T_individualized	Y1	0.890	4	① Teachers are well aware of my strengths and weaknesses; ② Teachers check my level of understanding; ③ Teachers give homework according to my abilities; ④ Teachers explain according to my level.
	Y2	0.902
	Y3	0.898
	Y4	0.912
	Y5	0.914
T_Interactive	Y1	0.853	5	⑤ Teachers frequently praise me as a means to encourage me to study more; ⑥ Teachers encourage me to challenge even a slightly difficult problem; ⑦ Teachers give me ample opportunities to present myself in class; ⑧ When I ask questions that I do not understand, my teachers kindly explain things again until I understand.
	Y2	0.904
	Y3	0.885
	Y4	0.890
	Y5	0.895
T_Pressure	Y1	0.718	4	② Teachers dislike students if they do not study hard; ③ My teacher emphasizes that our class should excel in the tests; ④ My teacher emphasizes that all students should complete their homework; ⑤ My teacher thoroughly inspects my homework.
	Y2	0.710
	Y3	0.714
	Y4	0.706
	Y5	0.730
T_relations	Y1	0.925	5	Relationship with teacher – ① He/She listens to me well; ② My teacher calls my name kindly; ③ When I say hello, he/she is welcoming; ④ My teacher often praises me; ⑤ My teacher knows me well.
	Y2	0.925
	Y3	0.905
	Y4	0.916
	Y5	0.923
P_authoritarian	Y1	0.712	2	① Parents ordered me to follow their words/what they say; ② Parents interfere with my work/small things.
P_autonomy	Y1	0.772	2	① Parents respect my decision; ② Parents allow me to choose what I want to do.

Management, Peer_attach, P_Ac_sup, P_interaction, T_individual, T_interaction, T_Pressure, and T_relations represent self-management, peer attachment, parental academy-supportive learning environment, parent–child interactions, teachers’ individualized teaching methods, interactive teaching methods, teachers’ academic pressure, and children’s relationships with teachers, respectively. The circled numbers are the item ids given by the KELS2013. P_authoritarian and P_autonomy represent authoritarian and autonomy-supportive parenting styles, respectively; these two variables are used for Level 2.