Previous studies have documented diagnostic bias and noted that its reduction could eliminate misdiagnosis and improve mental health service delivery. Few studies have investigated clinicians' methods of obtaining and using information during the initial clinical encounter. We describe a study examining contributions to clinician bias during diagnostic assessment of ethnic/racial minority patients. A total of 129 mental health intakes were videotaped, involving 47 mental health clinicians from 8 primarily safety-net clinics. Videos were coded by another clinician using an information checklist, blind to the diagnoses provided by the original clinician. We found high levels of concordance between clinicians for substance-related disorders, low levels for depressive disorders, and anxiety disorders except panic. Most clinicians rely on patients' mention of depression, anxiety, or substance use to identify disorders, without assessing specific criteria. With limited diagnostic information, clinicians can optimize the clinical intake time to establish rapport with patients. We found Latino ethnicity to be a modifying factor of the association between symptom reports and likelihood of a depression diagnosis. Differential discussion of symptom areas, depending on patient ethnicity, may lead to differential diagnosis and increased likelihood of diagnostic bias. Diagnostic assessment bias occurs when clinicians make systematic errors in the collection or processing of clinical information that could lead to misdiagnosis, 6 false-positives, or falsenegatives. 7 Reducing diagnostic bias is one way to eliminate misdiagnosis 8 and improve service delivery. But identification of the patient's main problem, which is the foundation for the proper treatment of psychiatric disorders, is challenging given the level of unavoidable uncertainty in diagnostic decision making. 9 In fact, the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) was expected to make substantial improvements to diagnostic formulation by offering a checklist of symptoms, whereby clinicians would first determine which diagnostic criteria were present, whether enough criteria had been fulfilled to justify the diagnosis, and then rule out medical conditions or other psychiatric conditions that could account for these symptoms. 10 However, it is not only the information collected in diagnostic assessment, but also how the information is applied in decision making that is critical for an accurate diagnosis. Paul Meehl 11 showed that "actuarial" methods (eg, formal, algorithmic procedures whereby symptoms are collected in a checklist and statistically analyzed to reach a prediction) for combining diagnostic information were superior to clinical judgments (eg, those that rely on human judgment to merge information, discuss it with others, and reach a diagnostic impression). Yet clinicians resist actuarial or statistical methods in diagnostic formulation. 12 A structured interview may seem to constrain clinicians to prescribed questions and cli...