Table 4.

Quality of quasi-experimental studies included in the systematic review

Study	Selectiona					Comparabilitya		Outcomea					Risk of bias
	1a) Int. group truly representative	1b) Int. group somewhat representative	2a) Cont. group from same community	3a) Secure record used	3b) Structured interview used	1a) Important factor controlled	1b) Additional factor controlled	1a) Blind assessment	1b) Record linkage	2a) Sufficient follow-up period	3a) Complete follow-up	3b) Attrition unlikely to affect bias
Arnetz & Theorell [60]	No	Yes	Yes	No	No	No	No	No	No	Yes	No	No	High
Baumgarten et al [61]	No	No	No	No	Yes	Yes	Yes	No	No	Yes	No	No	Moderate
Evans & Jaureguy [73]	No	Yes	Yes	No	No	No	No	No	No	Yes	No	No	High
Fujiwara et al [74]	No	No	Yes	No	No	No	No	No	No	Yes	No	No	High
Martina & Stevens [75]	No	No	No	No	No	No	No	No	No	Yes	No	Yes	High
Rosen & Rosen [76]	No	No	No	Yes	No	No	No	No	No	Yes	No	No	High
Stevens & van Tilburg [77]	No	No	No	No	No	Yes	Yes	No	No	Yes	No	No	High
Toseland et al [53]	No	No	Yes	No	No	No	No	No	No	Yes	No	Yes	High
White et al 1999 [62]	No	No	Yes	No	No	No	No	No	No	Yes	No	No	High
Winningham & Pike [63]	No	No	No	No	No	No	No	No	No	Yes	No	No	High
Bogat & Jason [78]	No	No	No	No	No	Yes	No	No	No	Yes	No	No	High
Fokkema & Knipscheer [79]	No	No	No	No	No	No	No	No	No	Yes	No	No	High
Mulligan & Bennett [80]	No	No	Yes	No	No	No	No	No	No	Yes	No	No	High
Rook & Sorkin [81]	No	No	No	No	No	Yes	Yes	No	No	Yes	No	No	High
Toseland & Smith [54]	No	No	No	No	No	No	No	No	No	Yes	No	Yes	High
Bergman-Evans [65]	No	No	No	No	No	No	No	No	No	Yes	No	No	High

^a Refer to Wells et al [48] for full description of these categories