2. Measurement
• The process of assigning numbers to objects in such a
way that specific properties of the objects are faithfully
represented by specific properties of the numbers.
• Such ways of assigning numbers do not attempt to
measure the total phenomenon, but only a specific set of
attributes.
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3. Measurement (cont.)
•Measurement is used to capture some “construct”
- For example, if research is needed on the construct of
“depression”, it is likely that some systematic
measurement tool will be needed to assess depression.
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4. Measurement
Measurement--defined as application of rules to
assign numbers to objects (or attributes).
Measurement rules--the procedures used to
transform the qualities of attributes into
numbers (e.g., type of scale used).
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5. Why bother assigning numbers?
quantifying something that is expected to vary.
individual differences -- premise that people will
vary (get different scores) on the attribute
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6. Scales of measurement
Three important properties:
Magnitude--property of “moreness”. Higher
score refers to more of something.
Equal intervals--is the difference between any
two adjacent numbers referring to the same
amount of difference on the attribute?
Absolute zero--does the scale have a zero point
that refers to having none of that attribute?
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8. Levels of Measurement
Nominal Scales - there must be distinct classes but these classes
have no quantitative properties. Therefore, no comparison can be made
in terms of one category being higher than the other.
For example - there are two classes for the variable gender -- males and
females. There are no quantitative properties for this variable or these
classes and, therefore, gender is a nominal variable.
Other Examples:
country of origin
biological sex (male or female)
animal or non-animal
married vs. single
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9. Nominal Scale
Sometimes numbers are used to designate
category membership
Example:
Country of Origin
1 = United States 3 = Canada
2 = Mexico 4 = Other
However, in this case, it is important to keep in
mind that the numbers do not have intrinsic
meaning 9
10. Levels of Measurement
Ordinal Scales - there are distinct classes but these
classes have a natural ordering or ranking. The
differences can be ordered on the basis of magnitude.
For example - final position of horses in a
thoroughbred race is an ordinal variable. The horses
finish first, second, third, fourth, and so on. The
difference between first and second is not necessarily
equivalent to the difference between second and third,
or between third and fourth.
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11. Ordinal Scales
Does not assume that the intervals between numbers are equal
Example:
finishing place in a race (first place, second place)
1 hour 2 hours 3 hours 4 hours 5 hours 6 hours 7 hours 8 hours
1st place 2nd place 3rd place 4th place
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12. Levels of Measurement (cont.)
Interval Scales - it is possible to compare differences in magnitude,
but importantly the zero point does not have a natural meaning. It
captures the properties of nominal and ordinal scales -- used by most
psychological tests.
Designates an equal-interval ordering - The distance between, for
example, a 1 and a 2 is the same as the distance between a 4 and a 5
Example - Celsius temperature is an interval variable. It is meaningful to
say that 25 degrees Celsius is 3 degrees hotter than 22 degrees Celsius,
and that 17 degrees Celsius is the same amount hotter (3 degrees) than 14
degrees Celsius. Notice, however, that 0 degrees Celsius does not have a
natural meaning. That is, 0 degrees Celsius does not mean the absence
of heat!
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13. Levels of Measurement (cont.)
Ratio Scales - captures the properties of the other types of
scales, but also contains a true zero, which represents the
absence of the quality being measured.
For example - heart beats per minute has a very natural zero
point. Zero means no heart beats. Weight (in grams) is also a
ratio variable. Again, the zero value is meaningful, zero grams
means the absence of weight.
Example:
the number of intimate relationships a person has had
0 quite literally means none
a person who has had 4 relationships has had twice as
many as someone who has had 2 13
14. Levels of Measurement Scales (cont.)
• Each of these scales have different properties (i.e.,
difference, magnitude, equal intervals, or a true zero point)
and allows for different interpretations.
• The scales are listed in hierarchical order. Nominal scales
have the fewest measurement properties and ratio having the
most properties including the properties of all the scales
beneath it on the hierarchy.
• The goal is to be able to identify the type of measurement
scale, and to understand proper use and interpretation of the
scale.
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15. Types of scales
Nominal scales--qualitative, not quantitative
distinction (no absolute zero, not equal intervals,
not magnitude)
Ordinal scales--ranking individuals (magnitude,
but not equal intervals or absolute zero)
Interval scales--scales that have magnitude and
equal intervals but not absolute zero
Ratio scales--have magnitude, equal intervals,
and absolute zero (so can compute ratios)
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16. 16
Type of Scale Numerical Operation Descriptive Statistics
Nominal Counting Frequency in each
category, percentage in
each category, mode
Ordinal Rank Ordering Median, range,
percentile ranking
Interval Arithmetic Operations on
Intervals between
numbers
Mean, standard
deviation, variance
Ratio Arithmetic Operations on
actual quantities
Geometric mean,
coefficient of variation
17. Rating Scales for Measurement
A scale represents a composite measure of
a variable;
it is based on more than one item.
Scales are generally used with complex
variables that do not easily lend
themselves to single-item or single-
indicator measurements.
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18. Rating Techniques for
Measurement
Some items, such as age, newspaper
circulation, or number of radios in the
house, can be adequately measured
without scaling techniques.
Measurement of other variables, such as
attitude toward TV news or gratification
received from going to a movie theater,
generally requires the use of scales.
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19. Simple Rating Scales
Rating scales are common in mass
media research.
Researchers frequently ask respondents to
rate a list of items such as a list of
programming elements that can be
included in a radio station’s weekday
morning show,
or to rate how much respondents like
radio or TV on-air personalities. 19
20. Simple Rating Scales
The researcher’s decision is to decide
which type of scale to use: 1 to 3? 1 to 5?
1 to 7?
1 to 10? 1 to 100? Or even a 0 to 9 scale,
which is commonly used by researchers
who don’t have computer software to
accept double-digit numbers (like 10).
Selecting a type of scale is largely a
matter of personal preference, 20
21. SPECIALIZED RATING
SCALES
Thurstone Scales
Thurstone scales are also called equal
appearing interval scales because of the
technique used to develop them and are
typically used to measure the attitude
toward a given concept or construct.
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22. SPECIALIZED RATING
SCALES
Reserahcer first collects a large number of
statements (Thurstone recommends at
least 100) that relate to the concept or
construct to be measured.
Next, judges rate these statements along
an 11-category scale in which each
category expresses a different degree of
favorableness toward the concept.
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23. SPECIALIZED RATING
SCALES
Reserahcer first collects a large number of
statements (Thurstone recommends at
least 100) that relate to the concept or
construct to be measured.
Next, judges rate these statements along
an 11-category scale in which each
category expresses a different degree of
favorableness toward the concept.
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24. SPECIALIZED RATING
SCALES
The items are then ranked according to
the mean or median ratings assigned by
the judges and are used to construct a
questionnaire of 20 to 30 items that are
chosen more or less evenly from across
the range of ratings.
The statements are worded so that a
person can agree or disagree with them.
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25. SPECIALIZED RATING
SCALES
The scale is then administered to a sample
of respondents whose scores are
determined by computing the mean or
median value of the items agreed with.
A person who disagrees with all the items
has a score of zero.
Thurstone scales are not often used in
mass media research, but they are common
in psychology and education research.
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26. SPECIALIZED RATING
SCALES
Guttman Scaling
Guttman scaling, also called scalogram
analysis, is based on the idea that items
can be arranged along a continuum in such
a way that a person who agrees with an
item or finds an item acceptable will also
agree with or find acceptable all other items
expressing a less extreme position.
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27. SPECIALIZED RATING
SCALES
a hypothetical four-item Guttman scale:
1. Indecent programming on TV is
harmful to society.
2. Children should not be allowed to
watch indecent TV shows.
3. Television station managers should
not allow indecent programs on their
stations.
4. The government should ban indecent
programming from TV. 27
28. SPECIALIZED RATING
SCALES
A Guttman scale requires a great deal of
time and energy to develop.
Although they do not appear often in mass
media research,
Guttman scales are common in political
science, sociology, public opinion research,
and anthropology.
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29. SPECIALIZED RATING
SCALES
Likert Scales
Perhaps the most commonly used scale in
mass media research is the Likert scale,
also called the summated rating approach.
A number of statements are developed with
respect to a topic, and respondents can
strongly agree, agree, be neutral, disagree,
or strongly disagree with the statements
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30. SPECIALIZED RATING
SCALES
Each response option is weighted, and each
subject’s responses are added to produce a
single score on the topic.
1. Only U.S. citizens should be allowed to
own broadcasting stations.
Strongly agree 5
Agree 4
Neutral 3
Disagree 2
Strongly disagree 1 30
31. SPECIALIZED RATING
SCALES
2. Prohibiting foreign ownership of
broadcasting stations is bad for business.
Strongly agree 1
Agree 2
Neutral 3
Disagree 4
Strongly disagree 5
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32. SPECIALIZED RATING
SCALES
Semantic Differential Scales
Another commonly used scaling procedure
is the semantic differential technique.
As originally conceived by Osgood, Suci,
and Tannenbaum (1957), this technique is
used to measure the meaning an item has
for an individual.
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33. SPECIALIZED RATING
SCALES
To use the technique, a name or a concept
is placed at the top of a series of seven-
point scales anchored by bipolar attitudes.
The bipolar adjectives that typically “anchor”
such evaluative scales are pleasant/
unpleasant, valuable/worthless, honest/
dishonest, nice/awful, clean/dirty, fair/unfair,
and good/bad.
Unique set of anchoring adjectives be
developed for each particular measurement
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