Diagnosing phobia reliability and validity issues:

Reliability: * Inter rater- high rel if 2 doctors give the same diagnosis/treatment to a person. * Intra rater- high rel if the same doctor gives the same diag/treatment to same p.

Validity: * Content val- form of assessment, how questions are asked and whether it asks the right things. * Criterion val- people with phobias should differ from people without (the fine line between people with a phobia and a fear). * Construct val- the doctors and assessors should be able to predict the person with a phobia’s behaviour without being in the situation. (for example, Rapee &Lim’s study on social phobic rating their skills lower). * Predictive val- predicting the outcomes of the treatments given to patients. The treatments should be successful as it means that the diagnosis was right initially. Comorbidity could be either reliability or validity issue.

Reliability:

Issues with assessment criteria * ‘Threshold issues’- very subjective criteria like the words used ‘persistent, excessive’ what a person feels a severe stress could be different to another person, which could lead to different interpretation between doctors and assessors.
Issues with methods of diagnosis * ‘Limited resources’- different clinics and doctors have different time limits, and some may priorities other patients more. * ‘Reliance on self report’- after the information about the patient is given to different doctors over time

Discuss issues related to reliability and validity of diagnosing phobias (24)

Reliability:

* Comorbidity- if a patient has a phobia and another mental disorder that has overlaps in symptoms, it could be difficult for rater to find out what is causing what and what kind of treatment they need. Issuing treatment will particularly be difficult, as the assessor might not know whether the side effects of one treatment will affect the other mental disorder. The inter or intra rater concordance might be affected by comorbidity as if the symptoms of a mental disorder surfaces at a greater level in the first interview or the self report, the patient is more likely to talk about that and when the symptoms go down in severity at the second interview, it could be likely that the assessor doesn’t know about the existence of comorbidity in this patient. It is common in social phobias, with depression.

* There is a very fine line between fear and phobia, the DSM-IV criteria is very subjective which means that different assessors may diagnose the same patients differently. Different assessors may have different interpretations which will affect the inter rater reliability and the treatment they