An individual’s mental health is measured by means of the mental health inventory 5 (MHI-5). The MHI-5 is an international standard for measuring mental health consisting of 5 questions on how the respondent felt in the 4 weeks prior to the survey:
1. Have you felt very nervous?
2. Have you felt so down in the dumps that nothing could cheer you up?
3. Have you felt calm and collected?
4. Have you felt downhearted and blue?
5. Have you felt happy?
The six response categories are:
all of the time, most of the time, a good bit of the time, some of the time, a little of the time, none of the time. Respondents can choose one out of six response categories for each question. On the basis of responses, a sum score is calculated (Van der Zee e.a., 1993). The order of the response categories is 5, 4, 3, 2, 1 and 0 for positive questions (3 en 5) . The reverse order applies to negative questions (1, 2 en 4). Subsequently, the scores of each respondent are calculated and multiplied by 4, resulting in a total score ranging from 0 (very unhealthy) to 100 (very healthy). A low score is indicative of a bad mental health. A score of 60 or below 60 is classified as mentally unhealthy.