One issue with diagnosing Phobic Disorders is Reliability. This is the consistency of a measuring instruments such as a questionnaire or scale. Internal Reliability is the extent to which a measure is consistent within itself and can be assessed using the split-half method which involves splitting the test I two and having the same participant do both halves of the test and then seeing how similar they are. External reliability is the extent to which a measure varies from one use to another and can be assessed using the test retest method which involves testing the same participant twice in the same test over a period of time and seeing whether the scores were similar. Inter-rater reliability is a way of testing external validity which involves comparing the ratings of two or more observers and checking for agreement in their measurements, it can be also used for interviews.
Reliability can be improved through the use of computerised scales. Kobak et al (1993) suggested that increased reliability occurs because there is less opportunity for the experimenter to affect the given answers. Also it helps with things such as people with social phobias as they may prefer to answer without the presence of a person in the room.
Kendler et al (1999) did a study which undermines the research into the classification and diagnosis of phobic disorders by using face to face and telephone interviews to diagnose phobias over one month and then eight years. He found that test-retest reliability for diagnosing phobic disorders was quite low and decreased with time. He thought this to be because of participant’s level of recall of past phobias. This undermines the reliability of research into the classification and diagnosis of phobic disorders because it shows that it is difficult to be confident in the research as it has such low reliability.
The reliability of Kendler’s study was also low because inter rater reliability because it was suggested that different clinicians made different decisions about the severity of symptoms in some phobias. This would reduce the reliability of the classification and diagnosis of phobic disorders as if each clinician sees the severity of symptoms as different they are likely to also classify and diagnose people differently.
Validity is also an issue in the classification and diagnosis of phobic disorders. Validity is the extent to which the diagnosis represents something that is real and distinct from other disorders and the extent that a classification measures what it claims to measure. There are three things that are measured within validity; Comorbidity which refers to the extent that two or more conditions co-occur, Concurrent Validity which establishes the value of a new measure of phobic symptoms by correlating it with an existing one, and Construct Validity which measures the extent that a test really does measure a target construct of phobias.
Eysnck (1997) supported comorbidity in diagnosing phobic disorders by finding that 66% of patients with one anxiety disorder are diagnosed with another. He says that because of this we should just say these people have an ‘anxiety disorder’ rather than many specific phobic disorders.This would support comorbidity in phobic disorders as it shows that phobic disorders do co-occur in many people.
Validity is also affected by cultural factors as some cultures have unique fears which could be seen as abnormal by other cultures. An example of this is Japan. They have a very different culture to ours and have a culture bound social phobia of embarrassing others in public which is diagnosed in Japan only. This shows the cultural differences on classifying and diagnosing phobias as if someone was to have this phobia in a western culture it would never be diagnosed.
is this a 24/24 answer?
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