This chapter explores the issues of reliability and validity of inspection frameworks and methods, and challenges and tensions in inspection frameworks and methods. Validity is an important aspect of thinking about effective inspection system as invalid inspection systems may lead to flawed judgments which will misguide administrative interventions and policy decisions and which are likely to have a negative impact on schools and teachers. We will introduce Kane’s (J Educ Meas 50(1):1–73, 2013) notion of argument-based approaches to evaluate the validity of inspection frameworks and provide two examples of how such an argument can be constructed. American Educational Research Association, American Psychological Association, and National Council on Measurement in Education. Standards for educational and psychological testing. American Educational Research Association, Washington, DC, 1999; American Educational Research Association, American Psychological Association, and National Council on Measurement in Education. Standards for educational and psychological testing. American Educational Research Association, Washington, DC, 2014) will then be used to describe five types of evidence to evaluate the validity of these arguments. For each of these sources of evidence we present examples of available studies.