Measurement and Scaling in Research

1. Unit 1.2:
Measurement and Scaling in
Research
Yusuf Babatunde Adeneye
President, GSB Ph.D. Club, USM
21/9/2019 SPSS/PLS Workshop 1

2. What is Measurement?
• The assignment of numerals to events/objects
• Variables are not measured at one specific level only. whether a
variable will be measured one way or another depends very much on
how it is conceptualized and on what type of indicators have been
used during measurement.
• The same variable can be measured in a various way (Sarantakos,
2005).
• This is to say that measurement can be done in various level.
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3. Characteristics of Measurement Scales
• Order: The relative sizes or positions of the descriptors. Order is
denoted by descriptors such as “greater than”, “less than”, and “equal
to”
• Distance: The characteristics of distance means that absolute
differences between the scale descriptors are known and may be
expressed in units.
• Origin: The origin characteristic means that the scale has unique or
fixed beginning.
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4. Nominal Scale or Qualitative Scale
• This is a scale whose numbers serve only as labels or for identifying
and classifying objects.
• Responses are merely categorized.
• Purpose of identification.
• Purpose of labelling.
• A person’s marital status can be single, married , widowed or divorced
labelled as 1 ,2 , 3 or 4
• Descriptive statistics (Mode, Frequency, and Percentage)
• Inferential statistics (Chi – squire test)
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5. Ordinal or Ranking Scale
• A ranking scale in which numbers are assigned to objects to indicate
the relative extent to which some characteristic is possessed.
• It places elements in order i.e. largest to smallest
• More or Less; High or Low; Greater or Lesser
• Descriptive statistics (Median and Percentile)
• Inferential statistics (Rank-order correlation, Friedman ANOVA)
• For ex: Political parties rank in Nigeria in term of seats occupied in
National Assembly. APC– 1st rank and PDP 2nd rank. There is no
meaning that “PDP is 2 times better than APC”. Difference between
1st and 2nd rank may not be equal to difference between other two
ranks, i.e. 4th and 5th.
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6. Interval or Rating Scale
• This is a scale in which the numbers are used to rate objects such that
numerically equal distances on the scale represent equal distances in
the characteristic being measured.
• It measures attitudes, and opinions.
• The gaps between whole numbers on the scale are equal.
• This scale does not a true zero but an arbitrary zero point.
• Descriptive statistics (Range, Mean, Median, Mode, and Standard
Deviation).
• Inferential statistics (Product-moment)
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7. Ratio Scale
• It allows the researcher to identify or classify objects, rank order the
objects and compare intervals or differences.
• It possesses all properties of nominal, ordinal and interval scales in
addition an absolute zero point.
• It is also meaningful to compute ratios of scale values ( Height,
weight, age and money).
• It allows comparison of differences between numbers.
• It allows all set of arithmetic operations including coefficient of
variation.
• It measures physical attributes like height, weight, distance, time,
income status, age, market share.
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8. Scaling
• Unique labels that are used to designate each value of the scale
Likert Scaling
• Degrees of agreement on a 1 (strongly disagree) to 5 (strongly agree)
scale
• Measurement of attitudes
• Easy to construct, administer, and understand
• More time-consuming
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9. Selecting an instruments/ Test of Measurement
• Three important questions need to be answered to select an
instrument:
• (i) Is our measure reliable?
• (ii) Is our measure valid?
• (iii) Is it practicable?
• NOTE: For a research study to be accurate, its findings must be both
reliable and valid.
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10. Reliability and Validity
• Reliability describes the consistency of an instrument or findings over
time. For example, findings should be the same if the study was
conducted over again.
• Validity describes information on what was intended to provide or
measure. The degree to which an instrument measures what it is
supposed to measure
• *Content Validity
• *Criterion related validity
• *Construct Validity
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11. Reliability
• A measuring instrument is reliable if it provides consistent results.
• Reliable instrument need not be a valid instrument
• But Valid Instrument is always reliable.
• Two aspects of reliability
*Stability: Consistent results with repeated measurements of the same
person and with the same instrument.
*Equivalence: Considers how much error may get introduced by
different investigators or different samples of the items being studied.
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12. Practicability
• Practicality can be judged in terms of economy, convenience and
interpretability.
*Length of measuring instrument, observation time, interview time and
data collection method are play important role in economic.
*Convenience: measuring instrument should be easy to administer
(proper layout of the measuring instrument, clear instruction to
respondent)
*Interpretability: Persons other than the designers of the test are to
interpret the results, supplemented by (a) detailed instructions for
administering the test (b) scoring keys (c) evidence about the reliability
and (d) guides for using the test and for interpreting results.
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13. Sources of Measurement Error
(1) Respondent : Little Knowledge in that area and transient factors like
fatigue, boredom and anxiety etc.
(2) Situation: Situation demands respondent not to give correct
answer.
(3) Measurer/Researcher: The interviewer can distort responses by
rewording or reordering questions.
(4) Instrument: Error may arise because of the defective measuring
instrument (complex words, ambiguous meanings, poor printing,
inadequate space for replies, response choice omissions).
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14. •Thank you for coming and listening
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