Corrigendum to “An Efficient Method for Computing Expected Value of Sample Information for Survival Data from an Ongoing Trial”

Vervaart M, Strong M, Claxton KP, Welton NJ, Wisløff T, Aas E. An efficient method for computing expected value of sample information for survival data from an ongoing trial. Med Decis Making. 2022;42(5):612–25. https://doi.org/10.1177/0272989X211068019

Due to a calculation error, the MB_EVSI values in Figure 2 of the above article were incorrect. The correct data is shown in the revised figure below.

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Figure 2

Marginal benefit (MBE_VSI), marginal cost of “approval with research” (MC_AWR) and, marginal cost of “only in research” (MC_OIR) given different durations of additional follow-up. Estimates are based on the model-averaged EVSI analyses for the increasing hazard data set (left) and decreasing hazard data set (right), trial costs of 5 life-months per month, 5 new patients receiving treatment each month, and a decision time horizon of 10 y.

In addition, on page 621, the values in the fourth paragraph under the “Expected net benefit of sampling” subsection were also affected by the same underlying error in the calculation of MB_EVSI values. The correct values are indicated below in bold.

Figure 2 illustrates that if AWR is recommended, the marginal benefit in terms of population model-averaged EVSI equals the marginal cost of continuing the trial at 22 and 23 mo of additional follow-up for the increasing and decreasing hazard data sets, respectively. These are the time points at which the ENBS is at a maximum. If OIR is recommended, the ENBS is at a maximum when the marginal benefit of delaying the decision until more data have been collected equals the marginal cost of continuing the trial and withholding approval, which is at 14 and 17 mo of additional follow-up for the increasing and decreasing hazard data sets, respectively.

These errors have now been corrected in the online version.