PSYC 510
Variables, Measures, & SPSS Practice Worksheet – Scale of Measurement
Review of Material: Scale of measurement – nominal, ordinal, interval/ratio/scale (Module 2)
Information from: Video “Measurements” and Ch. 3 Jackson “Scales (Levels) of Measurement”
Additional practice: Jackson ch. 3 Critical thinking check 3.1 Q2; MC self-test Q1 – 4 (answers in e-book for self-check)
Note: this is an OPTIONAL worksheet to practice applying some of this module’s key concepts. Please make sure you complete all assigned readings and watch this module’s presentations before attempting the worksheet! Try to complete it on your own, then check your answers with the answer key details (at the end of the document).
Practice 1 – Basic Concepts
Classify each operational variable below as nominal, ordinal, interval, ratio (or scale).
a. Degree of pupil dilation in a person’s eyes in a study of romantic couples (measured in millimeters)
b. Number of books a person owns.
c. A book’s sales rank on amazon.com
d. The language a person primarily speaks at home.
e. Nationality of the participants in a cross-cultural study of Canadian, Ghanaian, and French students.
f. A student’s letter grade in school.
g. Narcissism as operationally defined using the Narcissistic Personality Inventory (NPI – Raskin & Terry, 1988). This 40 question survey counts the number of statements selected associated with narcissism and provides a single score ranging from 0 – 40, with a higher score indicating greater levels of narcissism.
h. The question “If you were given the chance, would you reapply to your current job?” Options: Yes or No
i. The question “Do you have fun at work?” using a sliding scale akin to Likert. People are shown all numbers 1 – 10 like in Likert, but instead of having to select a solid value, the participant can “slide” a bar anywhere on that range.
Practice 2 – Application
Now that you can identify the scale of measurement, let’s practice doing this from a scenario. For each scenario, identify the independent and dependent variables, and the scale of measurement for each.
2-1. Does the level of seniority of a CEO affect a firm’s performance? CEO level of seniority was categorized as New (0-1 years at the firm); Moderate (2 – 7 years at the firm), and Advanced (8+ years at the firm). The firm’s performance was defined as the simple count of the number of acquisitions in the last year.
2-2. This study examines whether there is a difference between CEO narcissism in male and female CEOs. Narcissism was operationally defined as the CEO’s use of first-person singular pronouns in interviews (determined by counting the number of first-person singular pronouns divided by the sum of those pronouns plus all first- person plural pronouns for a percent ranging from 0 – 100%).
ANSWER KEY for Scale of Measurement
Practice 1 – Basic Concepts
Classify each operational variable below as nominal, ordinal, interval, ratio (or scale). Answers are in red. Remember, NOMINAL implies there are categories. ORDINAL requires magnitude. INTERVAL requires equidistant spacing between levels of magnitude, and RATIO requires an absolute zero. These are ordered from least to most powerful. You go with the scale of measurement that is the most powerful with all criteria met when labelling a variable’s scale of measurement. Remember, for the purposes of this class (and primarily in the social sciences), Likert-based questions will always be considered interval (or SCALE). “SCALE” encompasses both interval and ratio measurement types, as when it comes to statistical tests, we don’t have to differentiate.
a. Degree of pupil dilation in a person’s eyes in a study of romantic couples (measured in millimeters) RATIO / SCALE
b. Number of books a person owns. RATIO / SCALE
c. A book’s sales rank on amazon.com ORDINAL (has categories and magnitude, but it could be that the 3rd most popular may have 50000 more votes than the 4th, whereas there is only 24 vote difference between the 2nd and 3rd… so not necessarily equidistant spacing).
d. The language a person primarily speaks at home. NOMINAL (no magnitude)
e. Nationality of the participants in a cross-cultural study of Canadian, Ghanaian, and French students. NOMINAL (no magnitude)
f. A student’s LETTER grade in school. ORDINAL – much larger range for an F than any of the others, thus there is no equidistant spacing. However, there is categories and magnitude.
g. Narcissism as operationally defined using the Narcissistic Personality Inventory (NPI – Raskin & Terry, 1988). This 40 question survey counts the number of statements selected associated with narcissism and provides a single score ranging from 0 – 40, with a higher score indicating greater levels of narcissism. RATIO (since there is an absolute zero) or SCALE
h. The question “If you were given the chance, would you reapply to your current job?” Options: Yes or No NOMINAL (categories only)
i. The question “Do you have fun at work?” using a sliding scale akin to Likert. People are shown all numbers 1 – 10 like in Likert, but instead of having to select a solid value, the participant can “slide” a bar anywhere on that range. A sliding scale was described as akin to Likert – people are shown all numbers 1 – 10 like in Likert, but instead of having to select a solid value, the participant can “slide” a bar anywhere on that range. They don’t necessarily see the “inbetween” values, but the computer can provide the “exact” locations. This gives more range of data and so is typically considered more favorable / powerful by researchers in the debate of scale of measurement. Regardless, in this course and typically in the social sciences, Likert is considered “scale” (or “interval”), so that would be this scale of measurement as well. (As long as data is interval / ratio / scale you can run the same statistics, but it is good to know the theoretical differences! Remember – interval doesn’t have a true zero; ratio does. “Scale” is used to encompass both interval and ratio data).
Practice 2 – Application
Now that you can identify the scale of measurement, let’s practice doing this from a scenario. For each scenario, identify the independent and dependent variables, and the scale of measurement for each.
2-3. Does the level of seniority of a CEO affect a firm’s performance? CEO level of seniority was categorized as New (0-1 years at the firm); Moderate (2 – 7 years at the firm), and Advanced (8+ years at the firm). The firm’s performance was defined as the simple count of the number of acquisitions in the last year.
Remember “Independent” and “dependent” variables were covered last module. In this scenario, they want to see if level of seniority affects a firm’s performance. The independent variable (“cause”) then, is level of seniority. This is actually a subject variable (wasn’t manipulated). Regardless, the scale of measurement is ORDINAL because there is categories and magnitude, but no equidistant spacing within groups (new covers 24 month period; moderate is 5 years; advanced is an even larger range). Dependent variable is the “effect” and would be “firm’s performance”. Number of acquisitions is RATIO (or scale), as there can be zero, and there is equidistant spacing.
2-4. This study examines whether there is a difference between CEO narcissism in male and female CEOs. Narcissism was operationally defined as the CEO’s use of first-person singular pronouns in interviews (determined by counting the number of first-person singular pronouns divided by the sum of those pronouns plus all first- person plural pronouns for a percent ranging from 0 – 100%).
Since again nothing is manipulated, to find out what the independent (subject) variable is, you ask what they think is the “cause” vs. “effect”. In this scenario, they think gender may help explain narcissism. So, the independent variable is gender, and the dependent variable is narcissism. Gender is NOMINAL (only categories). Narcissism is RATIO / SCALE (percent range from 0 – 100% so there is a zero and equidistant units because each).
NOTE: There are still opportunities for extra practice! Try completing Jackson ch. 3 Critical thinking check 3.1 Q2 and MC self-test Q1 – 4 (answers in e-book for self-check)
