Lee 1994.

Study characteristics
Methods	Randomised controlled trial, Taiwan
Participants	60 hospital nurses suffering from either: insomnia, headache or gastrointestinal discomfort.
Interventions	1) Experimental: assertiveness training: six 2‐hour sessions on Monday, Wednesday and Friday at 2pm to 4pm on two consecutive weeks. The contents of sessions included the concept of beliefs and negative self‐statements, building a positive belief system, applying assertion to clinical settings and developing group and self‐reinforcement support systems. 2) Control: Traditional in‐service programme about computer applications in nursing.
Outcomes	Perceived Stress Scale, Rathus Assertiveness Schedule
Identification
Notes	PSS included in analysis 1.1
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Subjects were randomly assigned to one of two treatments: assertiveness training (AT) or alternate treatment control (ATC), which served as a control and contained updated knowledge of new computer technology for in patient settings." (p. 419)
Allocation concealment (selection bias)	Unclear risk	"Subjects admitted to the study agreed to random treatment assignment and a 2‐month commitment to the study. However, the subjects did not know whether they would receive treatment or control procedures during that time." (p. 425) Difficult to judge whether participants and/or investigators could possibly foresee assignment.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants not blinded.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Participants were not blinded whereas outcomes are self‐reported.
Incomplete outcome data (attrition bias) All outcomes	Low risk	"Of the respondents who initially chose to participate, three did not complete the study and were not included in the data analysis due to their failure to attend all sessions, failure to complete the questionnaire, or decision to leave hospital employment." (p. 425) Loss to follow‐up is below our review pre‐defined cut‐off point (three of the 60 (0.05%))
Selective reporting (reporting bias)	Low risk	All outcomes reported.
Other bias	Low risk	We did not find any indications of other sources of bias.