Measurement Principles

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Measurement Principles Scales
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Operationalization

• Concepts
• Generalized idea that represents something of
  meaning (abstract or concrete)
• Scales
• Device providing a range of values that
  correspond to different values in a concept
• Constructs
• Concepts that require multiple measures

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What Is An Attitude?
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Evaluating Measures

• Validity, or accuracy of a measure
• Face validity, predictive validity
• Reliability, or extent to which results are
  consistent over time
• Test-retest, equivalent forms
• Sensitivity, or ability to detect meaningful
  differences in peoples responses
• Agree/Disagree vs. numerous categories or
  points
• Multiple scales

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Other Measurement Issues

• Open-ended vs. closed-ended measures
• Labeling points in-between anchors (or
  endpoints)
• Forced- choice (even pts.) vs. Free-choice (odd
  pts.)
• Scale balance (equal magnitude positive/negative
  pts)
• Scale properties and level of measurement
• Assignment
• Order
• Distance
• Origin

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Levels of Measurement

• Nominal categories only
• Numbers identify and classify objects
• e. g., yes or no, male or female, purchase at
  Sears, J. C. Penneys or Target, brand numbers
• Ordinal categories in relative order, distance
  between each not known exactly
• Numbers still used to identify and classify
  objects, but in order
• e.g., income groups, ranking questions, less
  than, about the same, more than
• Interval numerically equal distances on a
  scale distance between each is constant and
  known (ratio if true zeroorigin)
• Numbers represent meaningful values distance can
  be computed
• e.g., age in yrs, exact dollar amount spent,
  numerical rating scales (scale of 1 to 7),
  composite scores, percentages

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Commonly Used Scales
DICHOTOMOUS RESPONSE FORMAT Do you plan on
purchasing a car within the next 12 months? Yes
No
PAIRED COMPARISON
In general, which is more important to you?
(circle one) CONVENIENCE or
PRIVACY
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Checklists Rank-Order

• Which of the following products do you own?
• Check all that apply
• _____ DVD
• _____ Ipod
• _____ DVR

• Rank the following home improvement stores in
  order of your preference. Assign the store you
  prefer most a 1, the store you prefer second a
  2 and the store you prefer least a 3.
• _____ Lowes
• _____ Home Depot
• _____ Ace Hardware

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Categorical and Numerical Scales
How likely would you be to attend the following
events?
How likely are you to attend next Saturdays
game? Not at all likely Extremely Likely 1
2 3 4 5
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Likert Scale Composite Scores

• Indicate how much you agree or disagree with the
  following statements by circling the number that
  best represents your feelings using the key
  below.
• Strongly Disagree Disagree Neutral
  Agree Strongly Agree
• SD D N A SA
• SD D N A SA
• My waiter/waitress today was courteous. 1 2
  3 4 5
• I was seated promptly. 1 2 3 4 5
• Overall, I was very satisfied with the service.
  1 2 3 4 5

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Semantic Differential Scale

• Please check one of the spaces between each set
  of words below that best represents your feelings
  
• Shopping on-line is
• Pleasant ____ ____ ________ ____ ____
  ____ Unpleasant
• Relaxing ____ ____ ____ ____ ____ ____
  ____ Stressful
• Foolish ____ ____ ____ ____ ____ ____
  ____ Smart

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Stapel Scales

• -5 -4 -3 -2 -1 courteous 1
  2 3 4 5
• -5 -4 -3 -2 -1 prompt 1
  2 3 4 5
• -5 -4 -3 -2 -1 reliable 1
  2 3 4 5

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Constant Sum

• Listed below are some television programs that
  will air next Sunday.
• Please divide 10 points among the four options
  to indicate how likely you are to watch each one.
  The more points you give a program, the more
  likely you are to watch it. You can give a
  program all ten points or no points or any number
  in between, but remember the total points you
  give all four programs must add to 10.
• Law Order _____
• Desperate Housewives _____
• Greys Anatomy _____
• Family Guy _____

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Alternative Forms
Smiling Faces