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Measurement. Measurement. The process whereby individual instances within a defined population are scored on an attribute according to rules Usually given a numeric score Measurement is meant to make comparisons among individual cases easier, more precise and more accurate. Measurement.

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  • The process whereby individual instances within a defined population are scored on an attribute according to rules
    • Usually given a numeric score
  • Measurement is meant to make comparisons among individual cases easier, more precise and more accurate
  • The easiest examples to understand involve the measurement of physical properties of objects
    • Height
    • Weight
    • Volume
  • Measuring intangibles such as opinion, intent, beliefs, etc. is difficult and open to error
measurement issues
Measurement issues
  • Validity: does the measure actually reflect the underlying concept?
    • Are you measuring what you intend to measure?
    • Accuracy
  • Reliability: does the measure perform the consistently from one occasion to another?
  • Precision/sensitivity: how large are the differences between adjacent categories/scores?
  • Efficiency: cost versus value of information
self report measures
Self-report measures
  • Memory
    • Forgetting
    • Bias
  • Social desirability
    • Respondent may believe a given answer is more acceptable to the researcher
  • Knowledge
    • Respondents may not know or understand the ideas
    • Often, respondents will answer questions without really knowing what they are about
self report measures1
Self-report measures
  • Sensitive to mood of the respondent
  • Sensitive to interview situation
  • Sensitive to data collection method
    • Internet
    • Interview
    • Paper and pencil
tests as measures
Tests as measures
  • Pretty much all tests of your knowledge would fall under the category of self-report measures
  • All tests are prone to some level and type of error
  • Many types of tests exist, each having its strengths and weaknesses
    • Multiple-choice
    • Fill in the answer
    • Essay
    • Apply the concept
the gre
  • FairTest analysis
  • ETS analysis
  • Internal states are only partially reflected in observable behavior, etc.
  • Behaviors are influenced by the situation, which may not be evaluated
  • May know they are being watched and change their behavior
  • Observer may engage in biased perception, interpretation, etc.
mechanical observation
Mechanical observation
  • Manifest behavior may not really reflect the underlying concept you think it does
    • Skin conductance
    • Website ‘hits’
  • Often intrusive to the point of being unnerving
    • Eye tracking
eye tracking
Eye Tracking

Source: Max Planck Institute at:

measurement levels
Measurement levels
  • Differences in ‘measurement level’ refer to the kind of information conveyed in the scores individual objects receive
    • Four levels: nominal, ordinal, interval, ratio
    • More advanced levels provide a greater amount of information with the score they assign
    • More advanced levels allow for more powerful statistical analysis of the data
nominal level measurement
Nominal-level measurement
  • Numbers are assigned to individual objects simply as a means to distinguish among them
    • Distinction without order
ordinal level measurement
Ordinal-level measurement
  • Scores indicate order, but not distance along some dimension
    • The difference between a one and a two may be greater or less than the difference between a two and a three
an ordinal level measure
An ordinal-level measure

Large dog

Score: 3

Small dog

Score: 1

Medium size dog

Score: 2

interval level measurement
Interval-level measurement
  • Scores indicate direction and distance
    • Intervals are of equal size—the difference between 1 and 2 is equal to the difference between 3 and 4
    • The zero point is arbitrary—does not indicate complete absence of the attribute
    • Many statistical analyses assume this level of measurement
ratio level measurement
Ratio-level measurement
  • Scores indicate order and distance from a true zero point
    • The units along the scale are equal
    • Allows for calculation of the ratio of one point on the scale compared to another
  • When measuring attitudes, behaviors, etc. there is bound to be a significant amount of measurement error
  • For reasons we will look at later, using multiple items/measures to create scores for individual objects improves the measurement of each one
  • We call measures combining multiple items to measure a single concept ‘scales’
  • Each item in a scale is supposed to measure the construct of interest, but it is possible that either:
    • The concept has more than one dimension, or
    • The items tap into more than one concept
  • To test for multidimensionality, statistical techniques are available
    • Factor analysis
    • Interitem correlations
scale development
Scale development
  • To improve the reliability/performance of the scale, a researcher may remove items that reduce reliability, etc.
  • May weight items according to their factor loadings
humor orientation scale
Humor orientation scale

Response categories:

1=strongly agree, 2=agree, 3=neutral, 4=disagree, 5=strongly disagree

  • I regularly tell jokes and funny stories when I am in a group
  • People usually laugh when I tell a joke or story
  • I have no memory for jokes or funny stories
  • I can be funny without having to rehearse a joke
  • Being funny is a natural communication style with me
  • I cannot tell a joke well
  • People seldom ask me to tell stories
  • My friends would say that I am a funny person
  • People don’t seem to pay close attention when I tell a joke
  • Even funny jokes seem flat when I tell them