Table 5.

Value of further research on IVIG for severe sepsis/septic shock: ENBS and optimal sample size of a trial, according to model for the synthesis of effectiveness evidence (see Table 2 for detailed specification of the models)

Scenarios for alternative synthesis models of effectiveness evidence	Maximum ENBS	Optimal sample size per arm ( n* )
M1	£ 136,703,882	1900
M2	£ 687,441,146	1200
M3	£ 1,010,953,361	800
M4a	£ 605,931,859	900
M4b	£ 365,050,246	800

The ENBS provides the societal payoff to the proposed research. It is computed as the difference between the value of sample information (EVSI) for a particular research design and the costs of sampling. IVIG, intravenous immunoglobulin; ENBS: expected net benefit of sampling.