This document discusses the importance of reliability and validity for assessment instruments. It defines reliability as consistency of results and validity as measuring what the instrument intends to measure. Intake interviews and mental status exams are described as important informal assessment tools that counselors use to gather client information. The document emphasizes that validity, or an instrument accurately measuring the intended construct, is crucial for assessment. It also notes validity can take different forms like content, construct, and criterion-related validity. Counselors should check an instrument's reported validity to ensure it is suitable for their needs.