Table 2.

The use of methods to reduce the risk of selection bias

	Trials (n = 152)
Recruiters blinded? – number (%)
No	1 (1)
Yes	2 (1)
Not stated	149 (98)
Used simple or restricted randomisation? – number (%)
Simple randomisation	4 (3)
Restricted randomisation	95 (63)
Not stated	53 (35)
Type of restricted randomisation used – number (%)
Permuted block	72/95 (76)
Minimisation	21/95 (22)
Other	2/95 (2)
Balanced for prognostic factors after restricted randomisation? – number (%)
No	42/95 (44)
Yes	53/95 (56)
Randomisation stratified by site of recruitment? – number (%)
No	41 (27)
Yes	67 (44)
Not stated	44 (29)