Measurement and Measurement and HypothesesHypothesesLesson 3 Lesson 3

Variables and AttributesVariables and Attributes

Attributes: characteristics/qualities that describe some Attributes: characteristics/qualities that describe some object or person; categories that make up variables. object or person; categories that make up variables.

Variables: logical groupings of attributesVariables: logical groupings of attributes

Variable = gender; Attributes = male and femaleVariable = gender; Attributes = male and female

Variable = occupation; Attributes = dentist, cop, truck Variable = occupation; Attributes = dentist, cop, truck driverdriver

Variables and AttributesVariables and Attributes

THEORY THEORY Variable (attributes) Variable (attributes) causation causation Variable (attributes) Variable (attributes)

Self-control theory Self-control theory Parenting (lack of Parenting (lack of supervision, lack of attachment) supervision, lack of attachment) causation causation Low self control Low self control Delinquency (drug use, vandalism, Delinquency (drug use, vandalism, truancy)truancy)

Dependent VariableDependent Variable

Depends on/caused by the independent Depends on/caused by the independent variablevariable

Example: Sentencing = DV; Defense Example: Sentencing = DV; Defense attorney/Judge = IVattorney/Judge = IV

Cause and Effect: IV = cause; DV = Cause and Effect: IV = cause; DV = effecteffect

Hypothesis Hypothesis

Hypothesis: an expectation about the nature of things derived from Hypothesis: an expectation about the nature of things derived from theory/empirical research.theory/empirical research.

Null Hypothesis (H0): hypothesis of no differenceNull Hypothesis (H0): hypothesis of no difference

Alternate Hypothesis (H1): our research hypothesisAlternate Hypothesis (H1): our research hypothesis

H1: Teenagers who listen to rap music will commit more violent acts than H1: Teenagers who listen to rap music will commit more violent acts than teenagers who listen to Yanni.teenagers who listen to Yanni.

H0: There will be no difference in the number of violent acts committed by H0: There will be no difference in the number of violent acts committed by teenagers who listen to rap music and teenagers who listen to Yanni.teenagers who listen to rap music and teenagers who listen to Yanni.

ConceptualizationConceptualization

Concepts: words or symbols in language that Concepts: words or symbols in language that we use to represent mental images.we use to represent mental images.

Example: “Crime”…we all have different Example: “Crime”…we all have different conceptions of different kinds of behaviors that conceptions of different kinds of behaviors that are considered criminal.are considered criminal.

Conceptualization: the mental process whereby Conceptualization: the mental process whereby imprecise notions are made more specific and imprecise notions are made more specific and precise.precise.

OperationalizationOperationalization

Operationalization: involves spelling out Operationalization: involves spelling out precisely how a concept will be precisely how a concept will be measured; the process of developing measured; the process of developing precise definitions. precise definitions.

Example Example

Topic Topic Juvenile Justice Juvenile Justice

Research question: what causes delinquency?Research question: what causes delinquency?

Theory: social bonding (Hirschi)Theory: social bonding (Hirschi)

Concept: involvement Concept: involvement

Conceptual definition: involvement in socially accepted/organized Conceptual definition: involvement in socially accepted/organized activities activities

Operational definition: participation in church, school, sports, hobbiesOperational definition: participation in church, school, sports, hobbies

Measurement of involvement: number of hours per week in church Measurement of involvement: number of hours per week in church activities, school activities, sports teams, socially accepted hobbiesactivities, school activities, sports teams, socially accepted hobbies

Levels of MeasurementLevels of Measurement

Nominal measuresNominal measures Lowest form categoricallyLowest form categorically No particular order; names or labels for characteristicsNo particular order; names or labels for characteristics Examples: states, cars, gender, race, college, SS #, Examples: states, cars, gender, race, college, SS #,

marital statusmarital status

Ordinal measuresOrdinal measures Logically rank ordered, some differences between Logically rank ordered, some differences between

categories but not even or observablecategories but not even or observable Examples: military rank, occupational status, fear of Examples: military rank, occupational status, fear of

crimecrime

Levels of MeasurementLevels of Measurement

Interval measuresInterval measures Equal and logical distances between categoriesEqual and logical distances between categories Examples: IQ tests (100-110 is some interval as 110-Examples: IQ tests (100-110 is some interval as 110-

120)120)

Ratio measuresRatio measures Usually very similar to intervals but also based on a Usually very similar to intervals but also based on a

true zero point.true zero point. Example: age, dollar value, # of prior arrests, BAC, etc.Example: age, dollar value, # of prior arrests, BAC, etc.

Validity and ReliabilityValidity and Reliability

Validity: measuring what you’re supposed to Validity: measuring what you’re supposed to measure.measure.

Does our cause produce the effect?Does our cause produce the effect?

Example: you’re studying delinquency and you Example: you’re studying delinquency and you survey adultssurvey adults

Validity error = misleading conclusions/no Validity error = misleading conclusions/no generalizationsgeneralizations

Threats to ValidityThreats to Validity

History effectHistory effect Example: UCR includes more behaviors than it Example: UCR includes more behaviors than it

used to (arson)used to (arson)

Maturation effectMaturation effect Example: aging out (adults versus teens)Example: aging out (adults versus teens)

Testing effect Testing effect Example: giving people a test, repeat several Example: giving people a test, repeat several

times, can cause the change (shooting targets)times, can cause the change (shooting targets)

ReliabilityReliability

Reliability: whether a particular measurement Reliability: whether a particular measurement technique, applied repeatedly to the same object, will technique, applied repeatedly to the same object, will yield the same result each time.yield the same result each time.

Example: Cop issuing speeding ticketsExample: Cop issuing speeding tickets

Officer’s judgment versus radar gun (more reliable)Officer’s judgment versus radar gun (more reliable)

Reliability is a concern every time a single observer is Reliability is a concern every time a single observer is the source of data because we have no way to guard the source of data because we have no way to guard against that observer’s subjectivity. against that observer’s subjectivity.