*3.3. Study Variables*

The Youth Environment Stressors Index [51] collects the joint scores of the following items, which all refer to events that happened in the previous year: someone close dying; moved or changed home; changed school; a close friend moved away; picked on or bullied at school or in the neighbourhood; parents separated or divorced; parent/guardian stopped working or lost a job; and brother/sister dropped out of school. All the items were categorised as: 1 = Strongly disagree; 2 = Disagree; 3 = Agree; 4 = Strongly agree.

The following questions were used as indicators of stressors: (a) Suddenly scared for no reason?—with answers: 0 = No, 1 = Yes, sometimes; 2 = Often; (b) Feeling blocked in getting things done?—with answers: 0 = No, 1 = Yes, sometimes; 2 = Often.

It is not properly a scale but rather a variable resulting from the summation of a number of items that give each individual a total count of environmental stressors. The resulting variable (total number of environmental stressors endorsed) is used as an ordinal variable and does not need to present the required properties on a scale that tries to measure a coherent dimension [51].

The Cultural Mistrust Index [52] was generated from the summation of the scores to different items: You should be suspicious of the native population from the beginning; You can trust the native population like members of your own group; The native population tend to keep their promises less; The native population tend to be honest with us; The native population tend to say one thing and do another; You should be cautious about what you say because it will be used against you; The native population usually tend to keep their word; The native population tend to feel superior to us. All the items were categorised as: 1 = Strongly disagree; 2 = Disagree; 3 = Agree; 4 = Strongly agree.

This index was developed from a proposal contained in Benkert, Peters, Clark and Keves-Foster [52], who used a more extensive instrument with high internal consistency (Cronbach's alpha = 0.89). In our sample, Cronbach's alpha was 0.89.

The Social Support Index [53] is the result of the summation of the scores of the following items: I have the social support of teachers; I have the social support of friends; I have the social support of parents/guardians; I have social support outside the family and school. All the items were categorised in the same way: 1 = Strongly disagree; 2 = Disagree; 3 = Moderately disagree; 4 = Neutral; 5 = Moderately agree; 6 = Agree; 7 = Strongly agree.

This index was developed from various scales used by Wang and Eccles [53], such as the Teacher Social Support (with a Cronbach's alpha of 0.80), the Peer Social Support (with a Cronbach's alpha of 0.82) and the Parent Social Support (with a Cronbach's alpha of 0.77) scales. In our study, Cronbach's alpha obtained a value of 0.53.

The Self-Esteem Index [54] consists of 10 items that allude to global feelings of self-esteem and self-perception. Five of the items are positive statements: I feel that I'm a person of worth, at least on an equal level with others; I feel that I have a number of good qualities; I am able to do things as well as most other people; I take a positive attitude toward myself; On the whole, I am satisfied with myself—and five others that are negative statements: All in all, I am inclined to feel that I am a failure; I feel I do not have much to be proud of; I wish I could have more respect for myself; I certainly feel useless at times; at times I think I am no good at all. All the items were categorised as: 1 = Strongly disagree; 2 = Disagree; 3 = Agree; 4 = Strongly agree.

The psychometric tests of the scale presented by Rosenberg [54] reflected a reproducibility coefficient of 0.92, which indicates excellent internal consistency. Test–retest reliability over a two-week period revealed correlations of 0.85 and 0.88, which indicates stability. In our analysis, Cronbach's alpha was 0.73.

The Academic Self-Efficacy Index [55] consists of the following items: I feel like I do well in school; It is easy for me to learn most things; Even when I study hard, I cannot do well on tests; When I try hard, I can learn most things; I can ge<sup>t</sup> good grades even when I do not try hard; There is no way a student like me can ge<sup>t</sup> good grades; and I think I am a smart person. All the items were categorised as: 1 = Very false; 2= More false than true; 3 = More true than false; 4 = Very true.

In the consistency analysis performed by Owen and Froman [55], for reliability estimation, alpha internal consistency estimates were 0.90. In the analysis of our data, Cronbach's alpha was 0.54.

The Cognitive Engagement Index [56] consists of the following items: With regards to learning at school, how often do the following occur: I enjoy learning new things; I ge<sup>t</sup> bored easily with school work; I feel good when I learn something new even when it is hard and I do homework whenever it is required. All the items were categorised as: 1 = Never; 2 = Few times; 3 = Most of the times; 4 = Always. This index was a composite of the variables validated by previous studies, such as Finn and Voelkl [56],

observing compliance or the non-compliance of the aforementioned school requirements. This index had a Cronbach's alpha of 0.43.
