Table 6. Original V&V40 gradation for the ‘Discretization Error’ credibility factor, and example possible gradations for PSM-CT and PSM-VC.

Changes highlighted in bold. [Original V&V40 example gradations reprinted from ASME V&V 40–2018, by permission of The American Society of Mechanical Engineers. All rights reserved].

Example gradation in ASME V&V40	Possible gradation for PSM-CT	Possible gradation for PSM-VC
(a) No grid or time-step convergence analysis was performed to estimate the discretization error. (b) Applicable grid or time-step convergence analyses were performed and their respective convergence behaviors were observed to be stable, but the discretization error was not estimated. (c) Applicable grid or time-step convergence analyses were performed and discretization error was estimated.	(a) No grid or time-step convergence analysis was performed to estimate the discretization error. (b) Applicable grid or time-step convergence analyses were performed, using one or a small number of patients, and their respective convergence behaviors were observed to be stable, but the discretization error was not estimated. (c) Applicable grid or time-step convergence analyses were performed and discretization error was estimated, using one or a small number of patients. (d) Applicable grid or time-step convergence analyses were performed and discretization error was estimated using a range of representative patients (e) Applicable grid or time-step convergence analyses are automatically performed on each new patient, and discretization error is estimated, and used in processing the results.	(a) No grid or time-step convergence analysis was performed to estimate the discretization error. (b) Applicable grid or time-step convergence analyses were performed and their respective convergence behaviors were observed to be stable, but the discretization error was not estimated, using one or a small number of subjects. (c) Applicable grid or time-step convergence analyses were performed and discretization error was estimated, using one or a small number of subjects. (d) Applicable grid or time-step convergence analyses were performed and discretization error was estimated, using a range of patients covering the virtual cohort.