Van Lankveld 2006a.

Methods	Design: randomised controlled trial Allocation method: urn randomisation (stratified design) Blinding: assessor blind
Participants	Diagnosis: primary vaginismus Criteria: DSM‐IV‐TR Setting: outpatient clinic Number: 117 Age: 28.6 years, SD = 6.9 Duration of vaginismus: 132 months, SD = 84
Interventions	Intervention 1: bibliotherapy + minimal contact (n = 43) Number of sessions: 6 Duration of sessions: 15 Therapist level: NA Adjunctive interventions: NA Intervention 2: bibliotherapy + group therapy (n = 38) Number of sessions: 10 Duration of sessions: 120 minutes Therapist level: senior therapist Adjunctive interventions: not stated Intervention 3: waiting list (n = 36) Number of sessions: NA Duration of sessions: NA Therapist level: NA Adjunctive interventions: not stated
Outcomes	Successful intercourse Drop‐outs Primary endpoint questionnaire Female Sexual Function Index Maudsley Marital Questionnaire Golombok Rust Inventory of Sexual Satisfaction
Notes	Bibliotherapy (manual and CD) comprised sexual education, relaxation exercises, systematic desensitisation, cognitive therapy and sensate focus therapy
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"A person not involved in assessment or treatment delivery performed urn randomization."
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Blinding is not possible for participants or therapists. However, most assessors were blinded to treatment status ‐ "assessment was performed at each research center by two research assistants who were not involved in treatment delivery and who were blinded to the treatment condition of participants, with the exception of one of two assessors in one research center, who was also involved in treatment delivery."
Incomplete outcome data (attrition bias) All outcomes	Low risk	24 of 117 participants dropped out of treatment. Drop‐outs were roughly equivalent across the 2 active treatment arms of the study (10 and 11 respectively) whilst 3 drop‐outs came from the waiting list control arm. Investigators used LOCF (last observation carried forward) to impute missing data for drop‐outs.
Selective reporting (reporting bias)	Unclear risk	Outcome data provided for all stated outcomes but we have no access to study protocols so cannot be certain other outcomes were not assessed
Other bias	Low risk	None suspected