What are the four sub-levels of diagnostic content validation in the NANDA-I terminology, and what distinguishes each sub-level?

The four sub-levels are initial validity (2.2.1), potential validity (2.2.2), advanced validity (2.2.3), and consolidated validity (2.2.4) of diagnostic content. They differ by both the number of experts and their expertise level: initial uses a small sample of beginner/advanced beginner experts; potential uses a large sample with the same beginner profile; advanced uses a small sample of proficient/expert experts; consolidated uses a large sample of proficient/expert experts.

Within NANDA-I's diagnostic content validation, sub-level 2.2.1, initial validity, is developed with a small number of experts with a predominantly beginner/advanced beginner profile. It relies on group evaluation techniques such as the Delphi technique, follows a more qualitative analysis, and confers only moderate potential for content validity. Sub-level 2.2.2, potential validity, also uses a beginner/advanced beginner expertise profile but with a large enough sample to generalize opinions; data analysis includes content validity indexes, proportions tests, and agreement coefficients. Sub-level 2.2.3, advanced validity, requires a small number of individuals with predominantly proficient/expert expertise, whose qualitative assessment is sufficient to confirm the relevance, adequacy, and clarity of the diagnosis's elements. Sub-level 2.2.4, consolidated validity, differs from advanced validity by using a large sample of experts with predominantly proficient/expert expertise, and it adds analyses such as content validity indexes, tests of proportions, agreement coefficients, and internal consistency of expert assessments; this makes it the most important and also the most difficult subdivision of diagnostic content validation.