Mache 2015b.

Study characteristics
Methods	Study design: RCT Study grouping: parallel group Unit of randomisation: individuals Power (power sample size calculation, level of power achieved): A sample size of a minimum of 40 physicians was selected for this pilot study after weighing statistical considerations along with logistical and resource constraints. A sample size of 40 provides a statistical power (2‐tailed, α = 0.05) of > 85%. Imputation of missing data: no imputation of missing data; per‐protocol analysis (only participants who took part in allocated intervention) and available‐case analysis (only participants for whom outcomes were obtained at 3 time points)
Participants	Country: Germany Setting: several clinic departments specialising in different medical specialties (e.g. internal medicine, paediatrics, neurology, and gynaecology) Age: mean = 28 years Sample size (randomised): 90 (according to information from authors; Mache 2017b [pers comm]) Sex: 51 women, 34 men Comorbidity (mean (SD) of respective measures in indicated, if available) at baseline: perceived stress (PSQ): IG = 58.1 (19.3), CG = 56.7 (19.8); both groups above cut‐off for moderate stress level Population description: hospital physicians from several clinic departments specialising in different medical specialties (e.g. internal medicine, paediatrics, neurology, and gynaecology); junior physicians in their first year after graduation Inclusion criteria: 1) employment as a hospital doctor; 2) working at least full‐time; 3) working experience of less than a year; 4) being able and willing to participate; 5) agreement to complete a survey at least twice Exclusion criteria: not specified Attrition (withdrawals and exclusions): 5 (IG = 3/45 (6.7%) exclusions, CG = 2/45 (4.4%) did not complete follow‐up questionnaires) Reasons for missing data: health reasons such as operation, accident (IG = 3), did not respond to follow‐up questionnaires, reasons not specified (CG = 2)
Interventions	Intervention: psychosocial resilience training (n = 45; according to information from authors; Mache 2017b [pers comm]) delivery: face‐to‐face; group sessions (maximum 12 participants (4 groups)); sessions involve: psycho‐education (theoretical input), watching videos, discussions, experiential exercises, and home assignments providers: 2 psychologists delivered the intervention. Both of them were familiar with cognitive behavioural and solution‐focused work in group settings. duration of treatment period and timing: 12 weekly 2‐hour sessions description: resilience training in this study focused on a number of objectives: for example, instructing and promoting fundamental communication, goal‐setting, improving emotional problems, increasing motivation, self‐efficacy, etc. .focus of the group work was the work situation, but any kind of topic was acceptable; main focus was on coping strategies, support between the participants, and solutions and goals for the future objectives: instructing and promoting fundamental communication, goal‐setting, improving emotional problems, increasing motivation, self‐efficacy, etc. 12 sessions: (1) Introduction: “Day‐to‐day working life of a hospital physician,” (2) self‐esteem and self‐awareness, (3) resilience, (4) positive thoughts and emotions, (5) cognitive behavioural training, (6) goal setting, (7) social support, (8) communication, (9) conflict handling, (10) dealing with difficult decisions, (11) coping with work‐related stress and relaxation, and at the end (12) session evaluation; Sessions also included how to speak up to supervisors and senior physicians, questioning their professional actions, seeking guidance about one’s own clinical performance, and reporting one’s mistakes compliance: not specified integrity of delivery: not specified economic information: not specified theoretical basis: based on principles of cognitive behavioural training and solution‐focused group work (Bamberger 1999) Control: no intervention (n = 45; according to information from authors; Mache 2017b [pers comm]) (received no training but answered the questionnaire at baseline and follow‐up)
Outcomes	Outcomes collected and reported: Primary outcome resilience ‐ Brief Resilient Coping Scale perceived stress ‐ PSQ self‐efficacy ‐ SWOP‐K9 optimism ‐ SWOP‐K9 job satisfaction ‐ German version Copenhagen Psychosocial Questionnaire Time points measured: 1) pre‐intervention; 2) post‐intervention (after 3‐month intervention); 3) 3‐month follow‐up (3 months post‐intervention/6 months after baseline) Adverse events: not specified
Notes	Contact with authors: We contacted authors for the number of participants randomised and potential per‐protocol analysis (Mache 2017b [pers comm]) Study start/end date: 96 junior physicians included between February and August 2014; exact study dates not specified Funding source: not specified Declaration of interest: not specified Ethical approval needed/obtained for study: not specified if approved; all procedures in accordance with the ethical standards of the responsible committee on human experimentation and with the Helsinki Declaration of 1975 Comments by authors: not specified Miscellaneous outcomes by the review authors: not relevant Correspondence: Dr Stefanie Mache, Institute for Occupational and Maritime Medicine (ZfAM), University Medical Center Hamburg‐Eppendorf, Seewartenstrasse 10, 20459 Hamburg, Germany; s.mache@uke.de
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "physicians were randomized into an intervention and control group." Quote: "Baseline data on gender, age, and perceived health indicate only small, insignificant differences between the control and the intervention group." Judgement comment: insufficient information about random sequence generation to permit judgement of ‘Low risk’ or ‘High risk’; RCT and verified baseline comparability of groups for sociodemographic characteristics and perceived health; baseline comparability for outcome variables unclear
Allocation concealment (selection bias)	Unclear risk	Judgement comment: insufficient information about allocation concealment to permit judgement of ‘Low risk’ or ‘High risk’
Blinding of participants and personnel (performance bias) Subjective outcomes	High risk	Judgement comment: blinding of participants and personnel probably not done (face‐to‐face intervention) and the outcome is likely to be influenced by lack of blinding
Blinding of outcome assessment (detection bias) Subjective outcomes	High risk	Judgement comment: insufficient information about blinding of outcome assessment (online questionnaires); however, due to potential performance bias (no blinding of participants), the review authors judge that the participants' responses to questionnaires may be affected by the lack of blinding (i.e. knowledge and beliefs about intervention they received)
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "Of the 45 participants in the intervention group, three were excluded due to health reasons (operation, accident). In addition, two participants of the control group did not respond to the follow‐up questionnaires. In sum, 42 physicians took part in the intervention group, and 43 participated in the control group." Judgement comment: 90 randomised (according to information received from authors); in part, reasons for missing data unlikely to be related to true outcome with relative balance in missing data between groups (IG: 3 exclusions due to health reasons), CG: 2 did not complete follow‐up (reasons not specified); available‐case analysis (only participants for whom outcomes were obtained at 3 time points) and per‐protocol analysis (only participants who took part in allocated intervention)
Selective reporting (reporting bias)	Low risk	Judgement comment: no study protocol available, but it is clear that the published report includes all expected outcomes, including those that were prespecified