Sequence balance minimisation: minimising with unequal treatment allocations

Table 2 Illustrative example of sequence balance minimisation

Next allocation	Factor 1: gender (women)					Factor 2: ethnic group (white)					Allocation probabilities
Next allocation	Number allocated	Number required	Difference (required − allocated)	Imbalance score^a	Weight	Number allocated	Number required	Difference (required − allocated)	Imbalance score^a	Weight	Allocation probabilities
T1	0	1	1 − 0	1/3	0.4	0	1	1 − 0	1/2	0.6	0.42
T2	0	2	2 − 0	2/3	0.57	1	2	2 − 1	1/2	0.43	0.58

^aIf minimising on one factor, imbalance scores provide the respective assigning probabilities

ISSN: 1745-6215