This document contains Performance Standards which allow, in accordance with the principles of Guidance Document No. 34, determining the validation status (reliability and relevance) of similar and modified skin irritation test methods that are structurally and mechanistically similar to the RhE test method in OECD Test Guideline (TG) 498. These PS include the following sets of information: (i) Essential Test Method Components that serve to evaluate the structural, mechanistic and procedural similarity of a new similar or modified proposed test method, (ii) a list of 12 Reference Chemicals to be used for validating new or modified test methods and (iii) defined target values of reproducibility and predictive capacity that need to be met by proposed test methods in order to be considered similar to the validated reference methods. The purpose of Performance Standards (PS) is to provide the basis by which new similar or modified test methods, both proprietary (i.e., copyrighted, trademarked, registered) and non-proprietary, can be deemed to be structurally and mechanistically similar to a Validated Reference Method (VRM) and demonstrated to have sufficient reliability and relevance for specific testing purposes (i.e., scientifically valid), in accordance with the principles of Guidance Document No. 34).