Table 1 Therapist participant and secondary clinical data outcome measurements by time point

Therapist participant outcomes

 Demographics

Gender, ethnicity, age group, experience level

Pre-training

 Attitudes

Bespoke attitudinal questionnaire capturing therapist-perceived confidence and competence in working with clients with personality difficulties (for example, ‘I feel confident recognising, assessing, and deciding whether to take on clients with personality difficulties’) on 5 items (see Additional file 2: Appendix 2). Participants will be asked to judge to what extent the statement is true of them on a 5-point Likert scale from strongly disagree to strongly agree. There are no standard measures fit for purpose (to capture attitude and confidence towards working with individuals with personality difficulties). This novel measure has been piloted in previous workshops for TTad HICBT therapists.

Pre-training; Post-training; 3-month follow-up

 Quantitative workshop feedback

Therapists will answer a series of 4 questions about the delivery and content of the workshop (for example, ‘I found the workshop theoretically interesting’), rated on a 5-point Likert scale from ‘Strongly disagree’ to ‘Strongly agree’ (Additional file 3: Appendix 3). This 4-item questionnaire captures perceived theoretical interest, usefulness and presentation quality and acceptability of the training; and whether they would recommend to other therapists. There is no standard measure fit for this purpose; however, this bespoke scale has been piloted to capture feedback on previous workshops for TTad HICBT therapists.

Post-training

 Qualitative workshop feedback

Written qualitative questions capturing therapist feedback on training

Post-training

 Wellbeing

Therapist wellbeing will be assessed using the (adjusted) Short Warwick-Edinburgh Mental Wellbeing Scale (SWEMWBS) [41] 7-item (self-report measure capturing positive wellbeing experiences (for example, ‘I’ve been feeling optimistic about the future’). Therapists will rate the frequency of positive experiences on a 5-point Likert scale from ‘None of the time’ to ‘All of the time’. This version of the scale is adjusted to capture experiences over the past two weeks (adjusted from past week). This measure has previously been used to assess workforce wellbeing [42].

Pre-training; 3-month follow-up

 Impact of training

Written qualitative questions capturing therapist experiences of training impacts

Post-training; 3-month follow-up

 Burnout

Sussex Burnout Scale (SBS) [43]—a 3-item self-report measure of frequency of symptoms of burnout at work (for example, ‘I have little or no energy at work or feel exhausted by my job’). Participants will rate frequency of symptoms over the past month on a 5-point Likert scale from ‘Rarely/Never’ to ‘Everyday/Almost every day’ over the past month.

Pre-training; 3-month follow-up

 Presenteeism and absenteeism

Therapist presenteeism/absenteeism—presenteeism and absenteeism questionnaire (Additional file 4: Appendix 4)—4-item self-report measure capturing frequency of presenteeism and absenteeism from work (for example, ‘At work I have been bothered by physical or psychological problems’). Participants will be asked to rate the frequency of these experiences over the past month from ‘Not at all’ to ‘Nearly every day’. This novel measure will be used as there are no standard measures available fit for the purpose (brief, self-reported measure).

Pre-training; 3-month follow-up

Routine clinical outcomes on clients with personality difficulties (measured in 6 m before and after the workshop)

 Depression symptoms

Patient Health Questionnaire (PHQ-9 [44];)—a 9-item self-report measure of frequency of depression symptoms (for example, ‘Little interest or pleasure in doing things’). Respondents are asked to rate frequency of symptoms over the past 2 weeks on a 4-point Likert scale from ‘Not at all’ to ‘Nearly every day’. This scale is validated for use in adolescents and adults.

First and last session

 Anxiety symptoms

The Generalised Anxiety Disorder scale (GAD-7; [45])—a 7-item measure of anxiety symptom (for example, ‘Feeling nervous, anxious or on edge’) frequency over the past 2 weeks, scored on a 4-point Likert scale from ‘Not at all’ to ‘Nearly every day’.

First and last session

 Work and social functioning

Work and Social Adjustment Scale (WSAS; [46])—a 5-item measure of impairment in daily functioning (for example, ‘Because of my [problem] me ability to work is impaired’) rated on a 9-point Likert scale from ‘Not at all’ to ‘Very severely’.

First and last session

 Measure of personality difficulties

Standardised Assessment of Personality: Abbreviated Scale—Self Report version (SAPAS-SR; [47, 48])—8-item binary response (yes/no) measure of personality difficulties (for example, ‘In general, do you have difficulty making and keeping friends. This scale is adapted for use as a self-report questionnaire and respondents are asked to indicate ‘Yes’ when the experience applies to them ‘most of the time in most situations’. This scale has been widely used for rapid screening for personality difficulties within the TTad setting for research purposes and has been adopted into routine practice in some services [4, 5, 9].

First session /instance

 Qualitative experiences of treatment

Patient Experience Questionnaires

Treatment end