Chapter 7 Measurement and Scaling Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin

7-2 Overview of the Measurement Process Measurement: Assigning intensity (or amounts) to variables, constructs or objects

7-3 Construct Development Construct: A hypothetical variable made up of a set of component responses or behaviors that are thought to be related Construct development: Determining what specific data should be collected to define and measure the construct

7-4 Examples of Concrete and Abstract Features of Objects

7-5 Examples of Concrete and Abstract Marketing Measures

7-6 Scale Measurement The process of assigning descriptors to represent the range of possible responses to a question about a particular object or construct – Scale points: Designated degrees of intensity assigned to the responses in a given questioning or observation method

7-7 Single vs. Multiple Item Scales Single-item scale: A scale format that collects data about only one attribute of an object or construct Multiple-item scale: A scale format that simultaneously collects data on several attributes of an object or construct.

7-8 Four Basic Scale Levels Nominal Scale Respondents provide categorical descriptors as answers. Ordinal Scale Respondents express merely relative magnitudes between choices. Interval Scale Allows for absolute differences between scale points but does not contain a true zero. Ratio Scale Allows for absolute differences between scale points and contains a true zero.

7-9 Examples of Nominal Scales

7-10 Example of Ordinal Scales Which one statement best describes your opinion of an Intel PC processor? __ Better than AMD’s PC processor __ About the same as AMD’s PC processor __ Worse than AMD’s PC processor

7-11 Examples of Interval Scales

7-12 Examples of Ratio Scales

7-13 Evaluating Measurement Scales Scale reliability - Refers to the extent to which a scale can reproduce the same or similar measurement results in repeated trials Kinds of scale reliability: Test-retest Equivalent form Measuring Reliability Split-half Reliability Chronbach’s Alpha Other Methods

7-14 Evaluating Measurement Scales Scale validity - Assesses whether a scale measures what it is supposed to measure – Face validity: Do scale items look like they measure what they’re supposed to measure? – Content validity: The extent to which all relevant dimensions of the construct are measured by the scale. – Convergent validity: The extent to which there is measurement overlap among items in a scale/construct. – Discriminant validity: The extent to which one construct measures something different from another construct.

7-15 Criteria for Scale Development Ease of understanding of the questions Discriminatory power of scale descriptors: The scale's ability to discriminate between the categorical scale responses (points) 1-5 scale versus 1-7 scale Balanced versus unbalanced scales Equal vs. unequal # of positive vs. negative statements Forced or non-forced choice scales Does the scale contain a neutral/unsure point? Desired measure of central tendency and dispersion

Central Tendency and Dispersion Measures Central Tendency – Mode – Median – Mean Dispersion – Frequency Distribution – Range – Standard deviation

7-17 Relationships between Scale Levels and Measures of Central Tendency and Dispersion

7-18 Scales to Measure Attitudes and Behaviors Likert scale: An ordinal scale format that asks respondents to indicate the extent to which they agree or disagree with a series of belief statements about a given object

7-19 Scales to Measure Attitudes and Behaviors Semantic differential scale: A bipolar ordinal scale that captures a person's attitudes or feelings about a given object

7-20 Scales to Measure Attitudes and Behaviors Behavioral intention scale: A rating scale designed to capture the likelihood that people will exhibit some type of predictable behavior in a future time frame

7-21 Construct/Scale Development Process

7-22 Other Rating Scales Noncomparative rating scales: A scale format that requires a judgment without reference to another object, person, or concept Example: How would you rate the food at our restaurant on a scale of 1 to 10 (1=Low quality, 10 = High quality)?

7-23 Other Rating Scales Comparative rating scales: A scale format that requires a judgment comparing one object, person, or concept against another on the scale

7-24 Other Rating Scales Graphic rating scales: Uses a scale point format that includes some type of graphic continuum as the set of possible responses to a given question