Measuring Constructs: Indirect Measurement

Indirect Measurement

  • Indirect measurement
    • Conduct an elicitation study to elicit commonly held beliefs.
    • Develop questionnaire items to assess strength of commonly held beliefs.
  • Conduct an elicitation study
    • Take a sample of about 25 people from population of study.
    • In a focus group or interview setting, use open-ended questions.
    • Content analyze the responses into themes. To increase validity, this should be done by two researchers independently. List the themes from most frequently mentioned to least frequently mentioned.
  • Develop questionnaire items
    • Select the beliefs which are listed most often and convert each of these into a statement.
    • Recommended to include about 75% of all beliefs stated.
    • Pilot test these items by asking five people from the population of study to answer them and report any difficulty in understanding. If necessary make modifications.
  • Scoring
    • For each construct measured, the score (i.e. on a 7 point scale, range 1-7) is multiplied by the relevant evaluation score (i.e. on a -3 to +3 scale).
    • The resulting products are summed to create an overall construct score.
    • Using this method:
      • A positive score will indicate an individual is in favor of the behavior.
      • A negative score will indicate an individual is against the behavior.
      • Sample scoring materials from Francis JJ, Eccles MP, Johnston M, et al. Constructing Questionnaires Based on The Theory of Planned Behavior: A Manual for Health Services Researchers. Centre for Health Services Research: Quality of Life and Management of Living Resources. University of Newcastle: United Kingdom. 2004.
      • Behavior: measuring a patient's blood pressure, Construct: attitude Chapter Four Table
      • Sample elicitation study materials from Francis JJ, Eccles MP, Johnston M, et al. Constructing Questionnaires Based on The Theory of Planned Behavior: A Manual for Health Services Researchers. Centre for Health Services Research: Quality of Life and Management of Living Resources. University of Newcastle: United Kingdom. 2004.
    • Attitude
      • What do you believe are the advantages of X behavior?
      • What do you believe are the disadvantages X behavior?
      • Is there anything else you associate with your own views about X behavior?
    • Subjective Norms
      • Are there any individual or groups who would approve of your X behavior?
      • Are there any individual or groups who would disapprove of your X behavior?
      • Is there anything else you associate with other people's views about X behavior?
    • Perceived Behavioral Control
      • What factors or circumstances would enable you to X behavior?
      • What factors or circumstances would make it difficult or impossible for you to X behavior?
      • Are there any other issues that come to mind when you think about X behavior?
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