Construct validity in psychological tests.--Antecedent probability and the efficiency of psychometric signs, patterns, or cutting scores.--Wanted--a good cookbook.--When shall we use our heads instead of the formula?--Some ruminations on the validation of clinical procedures.--The cognitive activity of the clinician.--Schizotaxia, schizotypy, schizophrenia.--Mixed-group validation.--What can the clinician do well?--High school yearbooks.--Specific genetic etiology, psychodynamics, and therapeutic nihilism.--MAXCOV-HITMAX.--Why I do not attend case conferences.