Reliability of diagnosis Flashcards
What is inter-rater reliability?
This type of reliability occurs when clinicians make identical, independent diagnoses of the same patient. With refinements to DSM, this should be fairly high. However, a study by Beck et al found that when a group of 153 patients with SZ were each assessed by two different psychiatrists the diagnosis agreement rate was only 54%. This implies low inter-rater reliability for schizophrenia.
What is test-retest reliability?
This type of external reliability occurs when clinicians make the same SZ diagnosis of the patient on separate occasions from the same information. Although clinicians have detailed manuals to use we must accept that patients with SZ and their symptoms change with time.
RELIABILITY - Supporting research?
Culture of a clinician can be damaging for inter-rater reliability, as Copeland found that when given a description of a patient. 69% of US psychiatrists diagnosed them with SZ compared to only 2% of UK psychiatrists. This suggests that the culture of the psychiatrist can affect the reliability of diagnosis.
RELIABILITY - Further supporting research?
Read reported that the test-retest analysis is as low as 37% for SZ, which creates potential false positives and negatives. Shows that changing symptoms of SZ can lead to potential misdiagnosis and lack of medical care.
RELIABILITY - Improvement?
A way to improve reliability has been highlighted by Farmer, who found that a standardised interview technique, known as Present State Examination increases the reliability of diagnosis because it focussed on frequency and severity of symptoms. This makes diagnosis more reliable as all the patients are asked the same questions.
RELIABILITY - DSM?
Improved as it stripped the criteria from the diagnostic guide as it was difficult to differentiate between bizarre delusion and non-bizarre delusion. Mojtabi and Nicholson found that 50 psychiatrists failed to differentiate between these, so patients will receive the incorrect diagnosis. Supports the notion that the DSM has helped to increase the reliability of diagnosis.
