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• Objectives of Psychometrics:

  • To measure behavior (overt and covert)
  • To describe and predict behavior and personality (traits, states, personality types, attitudes, interests, values, etc.)
  • To determine signs and symptoms of dysfunctionality for case formulation, diagnosis, and basis for intervention/plan for action
• Psychological Testing vs. Psychological Assessment:

  • Psychological Testing:
  • Objective: Typically to obtain some gauge, usually numerical in nature, with regard to an ability or attribute
  • Focus: How one person or group compares with others (nomothetic)
  • Process: Testing may be individual or group in nature. The tester will typically add up the number of correct answers or responses without much regard for the how or mechanics of such content
• • Role of Evaluator: The tester is not the key to the process; one tester may be substituted for another without affecting the evaluation significantly
  • Skill of Evaluator: Requires technician-like skills in administering, scoring, and interpreting test results
  • Outcome: Yields test scores
  • Duration: Shorter, lasting from a few minutes to a few hours
  • Sources of Data: One person, the test taker only
  • Qualification for Use: Knowledge of tests and testing procedures
  • Cost: Inexpensive, especially with group testing
  • Psychological Assessment:
• • Objective: Typically to answer a referral question, solve a problem, or arrive at a decision through evaluation tools
  • Focus: The uniqueness of a given individual, group, or situation (idiographic)
  • Process: Assessment is typically individualized and focuses on how an individual processes information
  • Role of Evaluator: The assessor is key in selecting tests and drawing conclusions from the evaluation
  • Skill of Evaluator: Requires educated selection of evaluation tools, skill in evaluation, and organization of data
• • Outcome: Entails a logical problem-solving approach with multiple data sources
  • Duration: Longer, lasting from a few hours to a few days or more
  • Sources of Data: Collateral sources like relatives or teachers are used in addition to the subject of assessment
  • Qualification for Use: Knowledge of testing and other assessment methods, as well as the specialty area assessed
  • Cost: Very expensive, requires highly qualified professionals
• Assumptions about Psychological Testing and Assessment:

  • Psychological traits and states exist:
  • Trait: Characteristic behaviors and feelings that are consistent and long-lasting
  • State: Temporary behaviors or feelings that depend on a person's situation and motives at a particular time
  • Psychological traits and states can be quantified and measured
  • Test-related behavior predicts non-test-related behavior:
  • Postdict it: To estimate or suppose something that took place in the past
• • Predict: Say or estimate that a specified thing will happen in the future or will be a consequence of something
  • Tests and other measurement techniques have strengths and weaknesses
  • Various sources of error are part of the assessment process:
  • Error: Factors other than what a test measures influencing performance
  • Error variance: Component of test score attributable to sources other than the trait or ability being measured
  • Testing and assessment can be conducted in a fair and unbiased manner
  • Testing and assessment benefit society