(1) Sequence generation (checking for possible selection
bias)
We will describe for each included study the method used to generate
the allocation sequence in sufficient detail to allow an assessment
of whether it should produce comparable groups.
We will assess the method as:
• adequate (any truly random process, e.g. random number
table; computer random number generator);
• inadequate (any non random process, e.g. odd or even date
of birth; hospital or clinic record number); or
• unclear.
(2) Allocation concealment (checking for possible selection
bias)
We will describe for each included study the method used to
conceal the allocation sequence in sufficient detail and determine
whether intervention allocation could have been foreseen in advance
of, or during recruitment, or changed after assignment.
We will assess the methods as:
• adequate (e.g. telephone or central randomisation;
consecutively numbered sealed opaque envelopes);
• inadequate (open random allocation; unsealed or nonopaque
envelopes, alternation; date of birth);
• unclear