8.5.4.1 Validation of statistical analysis within ISM

A rigorous statistical analysis regarding the extent to which various ISM sampling strategies provide accurate estimates of the average has not yet been published. Information from simulation studies can be used to address this issue, and results from efforts conducted during development of this document are described in Section 4 and Appendix A. However, it is reasonable to state that this is not a “mature” area of study, meaning that the strengths and limitations of ISM from a statistical standpoint are only just now being rigorously explored. Given that the statistical foundation of ISM is critical to understanding its reliability in providing estimates of the mean for site evaluation, regulatory agencies may be reluctant to embrace ISM until more thorough statistical evaluation has been conducted and formal guidance that addresses these issues is available.