Effective Sample Size

Consider the case where you have observations on the IQ of six individuals.  Let say that three of the individuals are from California and three are from Florida.  Assume the following data structure: California: 90, 110, 130 Florida: 95, 100, 120 In this case, the mean IQ nationally is 107.5, the variance of the sample…

Calculating Optimal Trial Sample Sizes: EVSI

Chapter 7 of Decision Modelling for Health Economic Evaluation looks at the calculating the Expected Value of Sample Information (EVSI).  In particular, EVSI can answer the question of optimal sample sizes. The Wrong Way How do scientists currently decide on sample sizes?  Often they will do one of the following: “(i) estimate potential grant funding…