A psychological evaluation is an integration, not an administration. Scores are one input among several: a clinical interview, developmental and educational history, medical and mental-health history, relevant records, behavioral observations, standardized measures, and — where it is clinically indicated — information from a parent, teacher, or partner. The work is in reconciling all of that into an account that holds together.
Which measures are used depends on the person and the question in front of us: age, presenting concerns, history, any previous testing, what the situation requires by way of documentation, and what emerges as the evaluation proceeds. Not everyone receives every kind of measure. A battery that is right for one client doesn’t necessarily fit another, and an evaluation designed by habit rather than by question tends to produce a report that doesn’t truly answer the question. Where anything could affect the accuracy of results, validity is considered directly rather than assumed.