CRIM 430

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CRIM 430

• Lecture 3 Concepts, Operationalization, and
  Measurement

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Concepts to Measurement

• Conceptualization Process by which we specify
  precisely what we mean when we use certain
  termsworking agreements to keep everyone on the
  same page
• Indicators specification for determining the
  presence or absence of a concept
• E.g., crime seriousness (concept)?harm to victim
  (indicator)
• Dimensions Groupings within an indicator
• E.g., harm to victim (indicator)?physical harm,
  economic harm (dimensions)
• Conceptual definition Result of
  conceptualizationa working definition
  specifically assigned to a term
• Operational definition Definition that clarifies
  exactly how the concept will be measuredmost be
  specific and unambiguous
• Use the operational definition to conduct
  measurements in the real world
• These are decisions that you must make based on
  the literature and your expertise
• Not everyone will agree on how you define each
  levelyou must be able to justify your terms

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Measurement

• Process of assigning numbers or labels to units
  of analysis in order to represent conceptual
  properties
• Requires making observations and scoring those
  observations
• Measurement depends on the decisions made at the
  conceptual and operational definition levels

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Measures

• MeasuresVariables
• Measures should be exhaustive Represent all
  possible characteristics
• Measures should be exclusive Must be able to
  classify each observation in terms of one and
  only one attribute

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Levels of Measurement

• Nominal Variable has only characteristics of
  exhaustiveness and exclusiveness-
• No rank ordering
• Ordinal Variables whose attributes may be
  logically rank ordered but the difference between
  each attribute is not relevant or measured
• Interval Variables in which the distance between
  rank ordered attributes is meaningful
• Ratio Same as interval but are based on a true
  zero point

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Criteria for Measurement Quality

• ReliabilityConsistencyDoes a measurement
  technique yield the same result each time when
  repeatedly applied?
• ValidityAccuracyDoes an empirical measure
  adequately reflect the meaning of the concept
  under consideration?
• Good measurement has both reliability and validity