Table 1 Study outcome measures¹

Primary outcome

 Behaviour³ (face covering adherence) recorded at T3 (i.e. 1-month follow-up)

Self-report measure using item adapted from Fisher et al. (2020)

1

Behavioural gauge of frequency of adherence to wearing face coverings where required.

Secondary outcomes

 Intention⁴

Self-report Likert measure items adapted from Theory of Planned Behavior Scale Construction Guidelines reported by Ajzen (2006)

3

Statement of an individual’s motivations/ plans to engage in the target behaviour.

 Attitudes⁴

3

Statement of an individual’s beliefs/ endorsement of engaging in the target behaviour.

 Subjective norms⁴

1

Statement of an individual’s perceived beliefs relating to important other peoples’ views about their engagement in the target behaviour.

 Perceived behavioural control⁴

3

Statement of an individual’s perceived ability to successfully engage in the target behaviour.

 Barrier self-efficacy⁴

Self-report measure using items adapted from Hamilton et al. (2019)

6

Statement of an individual’s perceived ability to successfully engage in the target behaviour when faced with obstacles.