Table 4 Overview of main themes and associated subthemes

Theme 1: Reflecting on emotions during completion

 Reflecting on emotions

In many cases participants commented that completion enabled them to reflect on their emotions and their life, both good (e.g., friends) and more challenging (e.g., emotion difficulties):“If you needed to stop your life for a second just to think what’s going on in my life, is it healthy, am I feeling alright, how am I going to deal with the responsibilities?” (RP2)

 Offloading emotions

In many cases participants described a process of “releasing” their feelings during completion: “I felt calm when it was completed” (RP1)

 Help-seeking and aftermath

In a few cases participants described feeling differently about how they handled something in their life following completion: “It’s improved my anger […] I need to stop showing my temper, find another way to calm myself down to fix that situation” (RP2)

Theme 2: The importance of anonymity

 System anonymity

In some cases the anonymity of submitting to researchers was seen as valuable: “they won’t know who it is” (RP2), but in a few cases there was concern that schools could check responses and some instances where participants thought they would be identified as needing support: “others will see and might do something about it” (RP1)

 Surrounded by others during completion

In a few cases the presence of peers was sometimes considered acceptable, but in some cases participants worried others would see their answers: “it could make you feel exposed a little bit” (RP2)

Theme 3: Understanding what is going to happen

 Prior understanding of participation

In a few cases there was some lack of clarity on aspects of participation, including how long the process would take and how data would be used: “I didn’t really know where it was all going” (RP2)

 Understanding participation rights

There was some confusion about whether completion was compulsory and whether they could skip items: “you should say if you don’t want to do it you can leave the room” (RP1)

 Knowledge of purpose of research

Though some were unclear about elements of the research, in some cases participants indicated that they valued knowing that the study could help others in the future: “it was going into somewhere where it could help you know everyone that did have the problems” (RP2)

Theme 4: Ease of responding to items

 Complexity of mental health focus

In some cases the complexity of mental health was considered to give an opportunity for reflection (“you [wouldn’t] really usually think of those questions”; RP2), but in some other cases participants said this could also make questions difficult to understand and challenging to answer: “Questions that you didn’t even know the answer to” (RP2)

 Understanding of items/item clarity

In some cases some items were seen as difficult to understand, including issues around complex phrasing, temporal specifications (e.g., in the last two weeks…) and the context of questions (i.e., home versus school): “I had to ask a teacher like, to explain a question” (RP2)

 Ability of answer options to capture response

Participants described mixed perspectives about Likert scales. In a few cases participants commented that they facilitated nuance (“I think it was a good way to answer because it has like a different variety of answers”; RP2), in a few cases they were described as sometimes confusing (“it’s difficult to know what’s between”; RP1), and in a few cases these options were seen as restrictive (“if I could write the answers […] I would’ve explained why; RP2).

 Support from others

In a few cases participants reported asking others for support, including peers (“we were discussing it with each other”; RP2), and teachers, though teachers weren’t always viewed as knowledgeable about the measurement framework: “they didn’t even know how to explain it” (RP2)

Theme 5: Intensity of completion

 Length of measurement framework and time to complete

There were varying perspectives on how acceptable the measurement framework length was, with participants in some cases indicating acceptability (“I think it was the right length; RP2) and in some cases indicating it took too long: “it went on forever” (RP1)

 Repetition of items across the measurement framework

In a few cases participants felt that items across the measurement framework were sometimes repetitive: “some repeated itself and […] it’s kind of the same content” (RP2)

 Comfort level

In many cases participants commented on the sensitivity of questions, which in some cases they felt was sometimes “too personal” (RP1)

Theme 6: Interacting with the measure format

 Preference for computer format

In many cases computer-based completion was described as preferred to paper completion, offering increased security, anonymity, and accessibility: “it was easy ‘cause like I’m used to doing it on the computer” (RP2)

 Engaging with the visual format

In a few cases participants found the visual formatting difficult to navigate, particularly matching Likert options to individual items: “it was so close together you could make a mistake” (RP1)