Cantor 2014.

Methods	Design: randomised, wait‐list controlled trial with minimization and blinded outcome assessment. Duration of study: January 2008 to June 2012.
Participants	Number randomized: 80 participants randomized and 18 participants directly grouped for study convenience, resulting in 49 people in each group. Inclusion criteria: aged > 18 years; history of TBI that met, at minimum, American Congress of Rehabilitation Medicine criteria for mild TBI: a blow to the head followed by 1 of the following: loss of consciousness, period of being dazed and confused, period of post‐traumatic amnesia or clinical signs of altered neurological function; ≥ 3 months' post‐injury; English speaking; executive dysfunction (Frontal Systems Behavior Scale T score >64 or Wisconsin Card Sort Test‐4 < 4 categories completed); oriented to time, place and person (Galveston Orientation and Amnesia Test > 75); at least a 6th‐grade reading level; sufficient intelligence to benefit from treatment (full‐scale intelligence quotient > 75). Exclusion criteria: lack of mental capacity to give informed consent (measured using the Aid to Capacity Evaluation); active substance abuse, psychosis, or suicidality (assessed using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, 4th edition); other behaviour that precluded group participation (e.g. offensive behaviour, assessed through clinical interview); concurrent participation in other cognitive rehabilitation.
Interventions	Intervention: Short Term Executive Plus (STEP) programme 2 × 45‐minute group sessions (emotional regulation and problem solving) and 1 × 60‐minute individual session (attention training and advising) per day, 3 days per week, for 12 weeks, for a total of 108 sessions. Rolling admissions was used with a monthly start date for new group members. Group size was generally 4‐6 people. Control: wait‐list. Duration: 2 × 45‐minute group sessions, 1 × 60‐minute individual session per day, 3 days per week for 12 weeks.
Outcomes	Quality of life: Life‐3. Participation: Participation Objective Participation Subjective (POPS). Executive function: composite score. Problem Solving Inventory. Self‐efficacy questionnaire.
Notes	Setting: community dwelling participants, institutional intervention. Country: US. Duration of follow‐up: 12 weeks of intervention followed by assessment. Dropouts: 9. In the treatment arm, 8 withdrew prior to completion of 12 weeks, and 1 did not start treatment. Funding: Supported by the Centers for Disease Control and Prevention (grant no. 1R49CE001171‐01).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Although the study used random assignment with minimization and some participants were assigned to groups based on group size, we have used the term randomization throughout because this was the principal mode of group allocation." "We allocated 18 participants without randomization when this was necessary to keep the size of the treatment group between 3 and 8; these participants were allocated in strict order of qualification." Comment: method of random sequence generation not specified. Unclear whether minimization method of allocating 18 participants had introduced bias in random allocation.
Allocation concealment (selection bias)	High risk	Quote: "We entered scores into the Minim program to determine treatment allocation." Comment: authors using the software was likely to have unblinded the allocation sequence.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: though the wait‐list control design made it impossible to blind the participants, we rated this at high risk of bias since the self‐reported outcomes were likely to be influenced by the knowledge of allocation to active intervention group or the wait‐list group.
Blinding of outcome assessment (detection bias) Objective outcomes	Low risk	Quote: "Assessors were blind to allocation at all assessments conducted after randomization."
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: 9 dropouts from intervention arm were not due to treatment‐related reasons.
Selective reporting (reporting bias)	Low risk	Comment: all key outcomes mentioned in the protocol published in the clinical trials registry were reported.
Other bias	Unclear risk	Quote: "Another limitation is the reliance on self‐report measures of function." "narrative reports from STEP participants to the treatment team suggested the presence of benefits of treatment that we did not measure." Comment: unclear whether reliance on self‐report measures for functional outcomes instead of using objective real‐life measures would impact the internal and external validity of the interpretations from this trial.