Table II.

Operationalization of the quantitative process evaluation measures and variables used for characterization of students and high schools

Stress preventive initiatives	Respondents	Measure	Response categories	Explanation for variables used in the analyses and results
Process evaluation measure: dose delivered
Curriculum	Teachers	Teachers were presented with a short description of the HHS curriculum and asked: ‘Did you use the HHS curriculum during the school year 2016–17 among your first-year students?’	‘Yes’, ‘No’, ‘Don’t know’	Dose delivered at teacher level: ‘Yes’
Stress lessons	Students	Students were presented with a short description of each stress lesson and asked if they attended each lesson	‘Yes, definitely’, ‘Yes, I think so’, ‘No, I don’t think so’, ‘No, definitely not’	Dose delivered at class and school level: more than half of students reported ‘Yes, definitely’/‘Yes, I think so’. Dose delivered of stress lessons were categorized as high (4 lessons), medium (2–3 lessons) and low (0–1 lessons) dose
Time management initiative
	School coordinators	During this school year (2016–17): did the high school conduct a course about study skills for first-year students e.g. note taking methods, reading techniques or time management techniques?	‘No’, ‘Yes, among selected first-year students’, ‘Yes, among all first-year students’, ‘Don’t know’	Dose delivered at school level: ‘Yes, among all first-year students’ AND ‘Time management techniques’ selected
		What topics were covered in the study skills course (select all that apply)?	‘Note taking methods’, ‘Reading techniques’, ‘Time management techniques’, ‘Other. Write:’, ‘Don’t know’
	Students	Did you talk about time management techniques in class with a student counsellor?	‘Yes’, ‘Yes, we talked about it, but not with a student counsellor’, ‘No’, ‘Don’t know’	Dose delivered at class level: more than half of students reported ‘Yes’/‘Yes, we talked about it, but not with a student counsellor’ AND ‘Yes’ i.e. the student completed the time management worksheet
		Student were presented with a picture of a time management worksheet and asked: ‘Did you track how you spent your time for a week during this school year?’	‘Yes’, ‘No’, ‘Don’t know’
Stress policy	School coordinators	During this school year (2016–17): did your high school get a new or changed student health and well-being policy?	‘No, we do not have a health and well-being policy’, ‘No, we did not change our health and well-being policy during the school year’, ‘Yes, we made significant changes to our health and well-being policy during the school year’, ‘Yes, we have developed a new health and well-being policy during the school year’	Dose delivered at school level: ‘No, we did not change our health and well-being policy during the school year’/ ‘Yes, we have developed a new health and well-being policy during the school year’/ ‘Yes, we made significant changes to our health and well-being policy during the school year’ AND ‘Stress’ was included in the policy
		What type of issues does the policy cover?	‘Well-being’, ‘Stress’, ‘Alcohol’, ‘Sleep’, ‘Smoking’, ‘Physical activity’, ‘Food and meals’, ‘Loneliness’, ‘Drugs’, ‘Bullying’, ‘Other. Write:’
Half-yearly counselling sessions
	School coordinators	During this school year (2016–17): are the high school offering student counselling for all first-year students?	‘No’, ‘Yes, among selected first-year students’, ‘Yes, once among all first-year students during the school year’, ‘Yes, twice among all first-year students during the school year’, ‘Don’t know’	Dose delivered at school level: ‘Yes, twice among all first-year students during the school year’
	Students	Students were presented with a short description of the aim of the half-yearly student counselling and asked: ‘How many counselling sessions did you attend during this school year’?	‘None’, ‘1’, ‘2’, ‘3 or more’, ‘Don’t’ know’	Dose delivered at class level: more than half of students reported ‘2’
Annual coursework plan
	School coordinators	During this school year (2016–17): does the high school follow any of these principles/rules: Students know dates for when assignments are handed out well in advance (e.g. via an annual cycle of work) Students know assignment due dates well in advance (e.g. via an annual cycle of work) We have a limit on number of assignments per week	‘To a great extent’, ‘To some extent’, ‘To a lesser extent’, ‘Not at all’, ‘Don’t know’	Dose delivered at school level: all three questions were marked as: ‘To a great extent’
	Students	Here are some statements about your assignments:		Dose delivered at class level: more than half of students answered ‘Yes, in all courses’ in both statements about assignments AND ‘Always’ in the question about limit on number of assignments per week
		‘In my class we know when our assignments will be handed out well in advance’	‘Yes, in all courses’, ‘Yes, in most courses’, ‘Yes, but only in some courses’, ‘No’, ‘Don’t know’
		‘In my class we know assignment due dates well in advance’	See above
		‘How often does your teachers respect the limit on assignments per week?’	‘Always’, ‘Often’, ‘Sometimes’, ‘Rarely’, ‘Never’, ‘We don’t have a limit on assignments per week’
Process evaluation measure: dose received
Curriculum	Students	Students were presented with a picture of the cover of the HHS curriculum and asked: ‘Have you been taught the HHS curriculum during this school year?’	‘Don’t know’, ‘No, never’, ‘Yes, but only a few times’, ‘Yes, many times’	Dose received of the HHS curriculum: ‘Yes, but only a few times’/‘Yes, many times’
Stress lessons	Students	Students were presented with a short description of each stress lesson and asked if they attended each lesson	‘Yes, definitely’, ‘Yes, I think so’, ‘No, I don’t think so’, ‘No, definitely not’	Dose received of each stress lesson: ‘Yes, definitely’/‘Yes, I think so’. Dose delivered of stress lessons were categorized as high (4 lessons), medium (2–3 lessons) and low (0-1 lessons)
Time management initiative	Students	Did you talk about time management techniques in class with a student counsellor?	‘Yes’, ‘Yes, we talked about it, but not with a student counsellor’, ‘No’, ‘Don’t know’	Dose received: ‘Yes’/‘Yes, we talked about it, but not with a student counsellor’ AND ‘Yes’ i.e. the student completed the time management worksheet
		Students were presented with a picture of a time management worksheet and asked: ‘Did you track how you spent your time for a week during this school year?’	‘Yes’, ‘No’, ‘Don’t know’
Half-yearly counselling sessions	Students	Students were presented with a short description of the aim of the half-yearly counselling sessions and asked: ‘How many counselling sessions did you attend during this school year’?	‘None’, ‘1’, ‘2’, ‘3 or more’, ‘Don’t’ know’	Dose received: ‘2’/‘3 or more’
Annual coursework plan	Students	Here are some statements about your assignments:		Dose received: students answered ‘Yes, in all courses’ in both statements about assignments AND ‘Always’ in the question about limit on assignments per week
		‘In my class we know when our assignments are handed out well in advance’	‘Yes, in all courses’, ‘Yes, in most courses’, ‘Yes, but only in some courses’, ‘No’, ‘Don’t know’
		‘In my class we know assignment due dates well in advance’	See above
		‘How often does your teachers respect the limit on assignments per week?’	‘Always’, ‘Often’, ‘Sometimes’, ‘Rarely’, ‘Never’, ‘We don’t have a limit on assignments per week’
Process evaluation measure: appreciation
Curriculum	Students	Students were asked to rate how much they liked the HHS curriculum	Rating scale from 0 (worst) to 10 (best)	Average score
	Teachers	Teachers were asked to rate their level of agreement with five statements about the curriculum: ‘I liked that the curriculum was available online’, ‘The curriculum covered official learning goals defined by the Danish Ministry of Education’, ‘The curriculum was difficult to use’, ‘I will definitely use all or some of the curriculum again’, ‘The curriculum was too difficult for students in the first year of high school’	‘Strongly agree’, ‘Agree’, ‘Neither agree nor disagree’, ‘Disagree’, ‘Strongly disagree’	‘Strongly agree/Agree’, ‘Neither agree nor disagree’, ‘Disagree/Strongly disagree’
Time management initiative	Students	Students were asked to rate how much they liked the time management course and exercise, respectively	Rating scale from 0 (worst) to 10 (best)	Average score
Half-yearly counselling sessions	Students	Students were asked to rate how much they liked the half-yearly counselling sessions	Rating scale from 0 (worst) to 10 (best)	Average score
Variables used for characterization of students and high schools
Characterization of students
Gender	Students	Are you a boy or girl?	‘Male’/‘Female’	Male/female
Age	Students	When were you born?	‘Date’/‘Month’/‘Year’	Continuous
OSC	Students	Does your father/mother have a job? What is his/her job title?	Text field	Responses were coded from I (highest) to V. We added a Category VI to include economically inactive parents who receive unemployment benefits, disability pension or other kinds of transfer income. Each student was categorized by the highest-ranking parent into high (I–II), middle (III–IV) and low (V–VI) OSC
Immigrant background	Students	Where was your mother/father/you born?	‘Denmark’, ‘Poland’, ‘Turkey’, ‘Germany’, ‘Iraqis’, ‘Bosnia Herzegovina’, ‘Other. Write’, ‘Don’t know’	Based on the definitions of Statistics Denmark, each student was categorized as being Danish (having at least one parent born in Denmark regardless of own country of birth), a descendant (born in Denmark to both parents born outside Denmark) or an immigrant (born abroad to both parents born outside Denmark)
Perceived stress	Students	The Perceived Stress Scale 10-item version (PSS-10). The PSS-10 assesses the extent to which people find their life unpredictable, uncontrollable and overloaded	5-Point Likert scale ranging from ‘Never’ to ‘Very often’	Scores on the PSS-10 range from 0 to 40 with higher scores indicating higher perceived stress. The PSS-10 was categorized into low (0–13), moderate (14–26) or high (27–40) perceived stress
Contextual factors
School size	School coordinators	Number of students in the school year 2016–17	Text field	Mean number of students per high school
Student/teacher ratio	School coordinators	Number of students in the school year 2016–17	Text field	Number of students in the high school divided by number of teachers in the high school
		Number of teachers in the school year 2016–17	Text field
Student/student counsellor ratio	School coordinators	Number of students in the school year 2016–17	Text field	Number of students in the high school divided by number of school counsellors in the high school
		Number of student counsellors in the school year 2016–17	Text filed
School popularity	School coordinators	Our high school is a popular school which many young people want to attend	‘Strongly agree’, ‘Agree’, ‘Neither agree nor disagree’, ‘Disagree’, ‘Strongly disagree’	‘Strongly agree’/‘Agree’
Implementation capacity
Well-functioning student council	School coordinators	The student council at our high school is well functioning	‘Strongly agree’, ‘Agree’, ‘Neither agree nor disagree’, ‘Disagree’, ‘Strongly disagree’, ‘We don’t have a student council’	‘Strongly agree’/‘Agree’
Team working with health promotion and well-being	School coordinators	In this school year (2016–17): does your high school have a team working with health promotion and well-being?	‘Yes’, ‘No’, ‘Don’t know’	‘Yes’