Measuring behaviours Flashcards
What are the objectives of the “Measuring Behaviour” lecture?
◦ Define the quality of measures.
◦ Distinguish between subjective and objective measures.
◦ Identify advantages and disadvantages of different measures
List examples of health behaviors that can be measured
◦ Physical activity: any bodily movement produced by skeletal muscles that expends energy beyond resting levels.
◦ Sedentary behavior: any waking behavior characterized by an energy expenditure ≤ 1.5 metabolic equivalents while in a sitting, reclining, or lying posture.
◦ Sleep: loss of conscious awareness.
◦ Nutrition: the kinds of food that a person, animal, or community habitually eats
Why is it important to measure health behaviors?
Measuring health behaviors is important in the behavioral epidemiology framework, and has a ripple effect throughout the framework.
Define validity in the context of measurement properties.
The accuracy of an instrument in measuring what it seeks or claims to measure. Includes construct, criterion, and content validity.
Define reliability in the context of measurement properties.
The stability and consistency of the instrument
Define objectivity in the context of measurement properties
Free of bias, uncontaminated by the emotional aspects of personal assessment. High objectivity means the measure is reliable, valid, and free from bias.
Define responsiveness in the context of measurement properties
The ability of an instrument to detect important change from an individual perspective
Define Patient Acceptable Symptom State (PASS)
The value beyond which individuals consider themselves well or consider their health state as acceptable
What are potential sources of error that affect the quality of measures?
◦ Social desirability bias: Over-reporting healthy behaviors and under-reporting unhealthy behaviors.
◦ Recall bias: Not accurately remembering what happened.
◦ Human error: Lack of objectivity.
What are the two main categories of behavioral measures?
◦ Subjective measures
◦ Objective measures
Give examples of subjective measures
◦ Self or proxy-report.
◦ Diary/log.
◦ Questionnaire.
◦ Interview (e.g., phone survey).
◦ Physical Activity Questionnaire for Children (PAQ-C).
Give examples of objective measures
◦ Observation
◦ Monitor
◦ Pedometer
◦ Accelerometer
What are the advantages of self- or proxy-reports?
◦ Low cost.
◦ Quick and efficient.
◦ Information gathered on context or setting.
◦ Reliable
What are the disadvantages of self- or proxy-reports?
◦ Validity issues.
◦ Biases (social desirability, recall).
◦ Cannot capture all physical activity.
What does a pedometer measure, and what are its advantages?
◦ Measures steps/day and cadence (steps/min).
◦ Advantages: Less biases, fairly inexpensive ($15-30)
What are the disadvantages of using a pedometer?
◦ More participant burden
◦ No information on context, time, or intensity
◦ Does not capture non-ambulatory or water-based activity
◦ Older pedometers cannot tell intensity at all
What does an accelerometer measure, and what are its advantages?
◦ Main measure: minutes/day in different intensities of activity.
◦ Advantages: Less bias, intensity of activity, time-stamped, detailed (1 second interval), Bluetooth technology, captures physical activity, sedentary behavior, and sleep.
What are the disadvantages of using an accelerometer?
◦ Costly ($225-$450).
◦ More participant burden.
◦ Minimal information on context.
◦ May not capture non-ambulatory activity.
◦ Large amount of data to analyze
How do the accuracy and ease of assessment relate to the cost and time of measuring physical activity?
Doubly-labelled water is the most accurate but hardest to assess, while questionnaires are the easiest to assess but the least accurate. There is an inverse relationship between time/cost and accuracy
What are the three main objectives regarding measures of behavior discussed in the first lecture
◦ Define the quality of measures.
◦ Distinguish between subjective and objective measures.
◦ Identify advantages and disadvantages of different measures.
What are the three main objectives regarding measures of behavior discussed in the second lecture?
◦ Describe measures used for other health behaviors.
◦ Identify advantages and disadvantages of different measures.
◦ Explore future measures for health behaviors.
What are the characteristics of a 24-hour food recall?
◦ It is a subjective measure used in nutrition.
◦ It involves recalling what a person ate and drank the previous day.
◦ It is retrospective
What are the advantages of the 24-hour food recall?
◦ Provides detailed data.
◦ Bias is minimized.
◦ Comparable
What are the disadvantages of the 24-hour food recall?
◦ Often costly.
◦ Less practical for very large sample sizes.
◦ Requires intensive analysis.
◦ Social desirability bias.
◦ Difficult to measure portion sizes.
What are the characteristics of food records as a nutrition measure?
◦ It is a subjective measure.
◦ Involves recording everything a person eats and drinks.
◦ It is prospective.
◦ It is done for approximately 7 days
What are the advantages of using food records?
◦ Provides detailed data
◦ Comparable
What are the disadvantages of using food records?
◦ Often costly.
◦ Requires intensive analysis.
◦ More participant burden.
◦ Social desirability bias.
◦ Reactivity bias
What are the characteristics of a Food Frequency Questionnaire (FFQ)?
◦ It is a subjective measure used in nutrition.
◦ Asks how often a person consumes a type of food/drink (daily, weekly, monthly, yearly).
◦ It is retrospective.
◦ Can be targeted to get at specific foods or nutrients.
What are the advantages of using FFQs?
◦ Quick.
◦ Cheap.
◦ Appropriate for large samples.
◦ Easy analysis.
