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CLASSIFICATION AND ASSESSMENT:Reliability, Test retest, Split Half

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Abnormal Psychology ­ PSY404
VU
LESSON 15
CLASSIFICATION AND ASSESSMENT
Assessment is the process of gathering information from a new patient. It is the systematic collection and
analysis of information about a person's characteristics and behaviors.
A classification system consists of a list of various types of problems and their associated symptoms.
In Diagnosis we identify or recognize a disorder on the basis of its characteristic symptoms.
A classification system is used to subdivide or organize a set of objects. Classification system can be based
on various principles, and its value will depend primarily on the purpose for which they were developed.
Different classification systems are not necessarily right or wrong; they are simply more or less useful.
Clinical assessment and diagnosis are centered to the study of the psychopathology. Clinical assessment
refers to systematic evaluation and measurement and psychological, biological and social factors in an
individual presenting with a possible psychological disorder. Diagnosis is the process of determining
whether the particular problem that the individual has needs all the criteria as given in DSM-IV-R in the
classification of disorders.
Example A
Suppose your class fellow experiences sensations that make her believe she is having a heart attack.
Difficulty in breathing, rapid heart beat and burden on her chest. She is taken to the emergency of a hospital
and she is told that the problem is psychological and physically she is al right.
Example B
Your aunt is depressed, she has lost her husband. She does not eat, does not sleep, and does not go to her
work. You are worried. You want her to return to normal.
Example C
A teacher observes that one of her students is disruptive, unpopular with the class. What should be done
and how the problem should be treated.
When we frequently come across medical problems, psychological problems, social problems or a
combination of either of the two, we frequently ask how can we decide? How can we be sure, what
treatment is needed? How can we differentiate between different types of psychological disorders?
In the mental health field, we describe, classify, explain, select, predict, plan and evaluate to do all these
tasks; we need procedures and methods to measure and define psychological disorders.
Tools for Assessment
Assessment is the systematic collection and analysis of information about a person's characteristics and
behaviors. There are several assessment procedures, such as:
1. Interviews
2. Questionnaires
3. Psychological tests
4. Rating Scales
5. Observation
6. Behavior samples
Each assessment procedure is to judge according to the following criteria which includes
1.
Reliability
2.
Validity
3.
Standardization
4.
Utility
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Abnormal Psychology ­ PSY404
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1. Reliability
Reliability refers to consistency or repeatability of the results. Reliability is computed by several statistical
procedures. Reliability is expressed as a matter of degree. Usually, on a continuum of 0 to 1 where one
means perfect reliability, this is a rare thing. There are three types of reliability.
a.  Test Retest
b. Internal consistency
c.  Inter rater reliability
Test retest: is the consistency of a test results over time. The same test questionnaire or an interview
should yield the same results, when used on the same person twice (tested on two different occasions). This
type of reliability is important when compulsive behavior is being measured or anxiety is being measured.
Split Half (Internal consistency) A type of reliability is internal consistency or correspondence
(correlation) between test items. A questionnaire intended to measure potential for child abuse so we focus
on the concept of child abuse, now every item of the questionnaire should relate and measure the concept
of child abuse. If all the items on the questionnaire contribute to identify this concept then individual item-
item correlation will be high and individual item to total item score will be high.
Inter rater reliability A type, of reliability is Inter rater reliability or consistency among scorers or
observers. Independent judges, who are observing a person's behavior, come to the same conclusion. This
kind of reliability evaluates the agreement between two raters administering the same interview, rating the
same video of a person's behavior or observing a person's behavior in a particular setting. High inter rater
reliability increases the confidence that the procedure is measuring, what it is suppose to measure. It is clear
that an instrument measuring a behavior should be high in reliability if we want to draw conclusions from it.
For example: an intelligence test demonstrates low test retest reliability. It clearly shows that it is not
measuring intelligence.
While two observers, observe the same child in the classroom and agree in their ratings that his
intelligence should be high.
2. Validity
Validity is a method, which means does the test measure, what it has been designed to measure i.e. an
intelligence should measure intelligence, a personality test should measure personality then it is a valid
measure and it will give valid and accurate results. Suppose that a bag of sugar when put on the scale should
read its weight, every time the same bag of sugar is put on the scale should give the same reading. Then the
weighing scale is valid.
Kinds of Validity:
a.  Face validity
b. Criterion (Predictive validity and Concurrent validity)
c.  Content validity
d. Construct validity
Face validity does not by itself establish the test's trust worthiness. It simply conveys that the test and its
items should appear making sense to the test taker. This is not validity in the real sense. It's simply means
that a test on depression should include questions about how often a depressed individual cry or weeps. So
face validity is the apparent sense the test makes to the person who is taking it.
Predictive validity is a test ability to predict a person's future characteristics or behavior. We could
establish predictive validity by administering a test to a group of school students and predict their
performance for the future senior school i.e. predictive validity makes prediction about the individual's
future behavior based on his present behavior. When we ask questions like, Is an individual likely to become
anxious or depress in future? We are dealing with the concept of predictive validity.
Concurrent Validity: A test designed to measure student's present or current anxiety state e.g. should
produce anxiety scores that agree with school counseling records and parent's reports.
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Abnormal Psychology ­ PSY404
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Content validity: A test that displays high content validity reflects that it measures all important aspects of
the behavior, skill or quality that it is measuring. All achievements test and intelligence test and all teacher
made classroom test should have high content validity. All entrance exams and admission tests should have
high content validity (THEY SHOULD BE CONTENT BASED).
Construct validity: Construct validity measures what they are intended to measure and not something else.
Do achievement tests measure ability in a given subject area or do they measure something else? Some
students do very well on an achievement test and others do very poorly on multiple choice tests. Before any
test can be useful, it must meet the requirements of standardization and utility criteria as well.
3. Standardization
Standardization is process by which a certain set of standards or norms is determined for a technique in
order to make its use consistent across different measurements, e.g. the assessment might be given to a large
number of people who differ on important factors, such as age, race, gender, socio economic status and
diagnosis, where scores would then be used as a standard or norm for comparison purposes, e.g. if you are a
Pakistani, 19 years old male from a middle class background on your score on a psychological test should be
compared to the scores others like you.
4. Utility
A final criterion for deciding that an assessment procedure is worth employing is its utility or usefulness.
To be useful, the assessment procedure should be valid, reliable, standardized and useful.
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Table of Contents:
  1. ABNORMAL PSYCHOLOGY:PSYCHOSIS, Team approach in psychology
  2. WHAT IS ABNORMAL BEHAVIOR:Dysfunction, Distress, Danger
  3. PSYCHOPATHOLOGY IN HISTORICAL CONTEXT:Supernatural Model, Biological Model
  4. PSYCHOPATHOLOGY IN HISTORICAL CONTEXT:Free association, Dream analysis
  5. PSYCHOPATHOLOGY IN HISTORICAL CONTEXT:Humanistic Model, Classical Conditioning
  6. RESEARCH METHODS:To Read Research, To Evaluate Research, To increase marketability
  7. RESEARCH DESIGNS:Types of Variables, Confounding variables or extraneous
  8. EXPERIMENTAL REASEARCH DESIGNS:Control Groups, Placebo Control Groups
  9. GENETICS:Adoption Studies, Twin Studies, Sequential Design, Follow back studies
  10. RESEARCH ETHICS:Approval for the research project, Risk, Consent
  11. CAUSES OF ABNORMAL BEHAVIOR:Biological Dimensions
  12. THE STRUCTURE OF BRAIN:Peripheral Nervous System, Psychoanalytic Model
  13. CAUSES OF PSYCHOPATHOLOGY:Biomedical Model, Humanistic model
  14. CAUSES OF ABNORMAL BEHAVIOR ETIOLOGICAL FACTORS OF ABNORMALITY
  15. CLASSIFICATION AND ASSESSMENT:Reliability, Test retest, Split Half
  16. DIAGNOSING PSYCHOLOGICAL DISORDERS:The categorical approach, Prototypical approach
  17. EVALUATING SYSTEMS:Basic Issues in Assessment, Interviews
  18. ASSESSMENT of PERSONALITY:Advantages of MMPI-2, Intelligence Tests
  19. ASSESSMENT of PERSONALITY (2):Neuropsychological Tests, Biofeedback
  20. PSYCHOTHERAPY:Global Therapies, Individual therapy, Brief Historical Perspective
  21. PSYCHOTHERAPY:Problem based therapies, Gestalt therapy, Behavioral therapies
  22. PSYCHOTHERAPY:Ego Analysis, Psychodynamic Psychotherapy, Aversion Therapy
  23. PSYCHOTHERAPY:Humanistic Psychotherapy, Client-Centered Therapy, Gestalt therapy
  24. ANXIETY DISORDERS:THEORIES ABOUT ANXIETY DISORDERS
  25. ANXIETY DISORDERS:Social Phobias, Agoraphobia, Treating Phobias
  26. MOOD DISORDERS:Emotional Symptoms, Cognitive Symptoms, Bipolar Disorders
  27. MOOD DISORDERS:DIAGNOSIS, Further Descriptions and Subtypes, Social Factors
  28. SUICIDE:PRECIPITATING FACTORS IN SUICIDE, VIEWS ON SUICIDE
  29. STRESS:Stress as a Life Event, Coping, Optimism, Health Behavior
  30. STRESS:Psychophysiological Responses to Stress, Health Behavior
  31. ACUTE AND POSTTRAUMATIC STRESS DISORDERS
  32. DISSOCIATIVE AND SOMATOFORM DISORDERS:DISSOCIATIVE DISORDERS
  33. DISSOCIATIVE and SOMATOFORM DISORDERS:SOMATOFORM DISORDERS
  34. PERSONALITY DISORDERS:Causes of Personality Disorders, Motive
  35. PERSONALITY DISORDERS:Paranoid Personality, Schizoid Personality, The Diagnosis
  36. ALCOHOLISM AND SUBSTANCE RELATED DISORDERS:Poly Drug Use
  37. ALCOHOLISM AND SUBSTANCE RELATED DISORDERS:Integrated Systems
  38. SCHIZOPHRENIA:Prodromal Phase, Residual Phase, Negative symptoms
  39. SCHIZOPHRENIA:Related Psychotic Disorders, Causes of Schizophrenia
  40. DEMENTIA DELIRIUM AND AMNESTIC DISORDERS:DELIRIUM, Causes of Delirium
  41. DEMENTIA DELIRIUM AND AMNESTIC DISORDERS:Amnesia
  42. MENTAL RETARDATION AND DEVELOPMENTAL DISORDERS
  43. MENTAL RETARDATION AND DEVELOPMENTAL DISORDERS
  44. PSYCHOLOGICAL PROBLEMS OF CHILDHOOD:Kinds of Internalizing Disorders
  45. LIFE CYCLE TRANSITIONS AND ADULT DEVELOPMENT:Aging