Measuring variables unit 4
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Measuring VariablesMeasuring VariablesSARISA BORIPET 55810262KHANITTA MEEPRADIT 55810250
13/04/23 1
OutlineOutline
• An Overview of MeasurementAn Overview of Measurement• Constructs and Operational DefinitionsConstructs and Operational Definitions• Validity and Reliability of MeasurementValidity and Reliability of Measurement• Scales of MeasurementScales of Measurement• Modalities of MeasurementModalities of Measurement• Other Aspects of MeasurementOther Aspects of Measurement
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An Overview Of MeasurementAn Overview Of Measurement
• The research processThe research process– Find an unanswer question– Forming a hypothesis– Developing a research study– Defining and measuring the variables
• VariablesVariables : characteristics or conditions that change or have different values for different individuals
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Aspects of measurementAspects of measurement
• Not a one to one relationship– Variable being measured : Measurements
obtained• Usually several different options for measuring
particular variable
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ExampleExample
Knowledge for each studentKnowledge for each studentMeasureMeasure
An exam
An essay
A set of problems
Impossible to look inside each student’ head
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The selection of a measurement The selection of a measurement procedureprocedure
• The general process of measurement
• The different measurement options
• The consequences of each option
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Constructs And Operational Constructs And Operational DefinitionsDefinitions
• Constructs Definitions
• Operational Definitions
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Constructs DefinitionsConstructs Definitions
• Hypothetical attributes or mechanisms that help explain and predict behavior in a theory
External StimulusExternal Stimulus
External behavior External behavior
Constructs Constructs
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Operational DefinitionsOperational Definitions
• A procedure for measuring and defining a construct
Definition and Measurement of the hypothetical construct Definition and Measurement of the hypothetical construct
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Example : Operational Definitions Example : Operational Definitions
Intelligence IQ
Hunger ?Hunger ?
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Using Operational DefinitionsUsing Operational Definitions
A research study A research study areare
hypothetical constructshypothetical constructs
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OutlineOutline
• An Overview of MeasurementAn Overview of Measurement• Constructs and Operational DefinitionsConstructs and Operational Definitions• Validity and Reliability of MeasurementValidity and Reliability of Measurement• Scales of MeasurementScales of Measurement• Modalities of MeasurementModalities of Measurement• Other Aspects of MeasurementOther Aspects of Measurement
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Validity and and Reliability of Measurement
• Validity of Measurement
• Definitions of Validity
• Reliability of Measurement– Type and Measures of Reliability
• The Relationship Between Reliability and Validity
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Validity of MeasurementValidity of Measurement
• Validity : first criterion for evaluation a measurement procedure
• Definition– The validity of a measurement procedure
is the degree to which the measurement process measures the variable that it claims to measure.
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Methods for Assessing the Validity Methods for Assessing the Validity of Measurement of Measurement
• Face Validity
• Concurrent Validity
• Consistency of a Relationship
• Predictive Validity
• Construct Validity
• Convergent and Divergent Validity
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Face ValidityFace Validity
• Definition of Face Validity : Simplest and least scientific
• Concerns the superficial appearance
IQ IQ TestTest
Logic, reasoning, background knowledge, good memoryLogic, reasoning, background knowledge, good memory
IntelligenceIntelligence
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Concurrent ValidityConcurrent Validity
• The scores obtained from the new measurement technique are directly related to the scores obtained from another
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Consistency of a Relationship
• The validity (and reliability) of measurement a can be established by demonstrating the consistency of a relationship between two different measurements
Test of IQTest of IQ
Score from a STANDARDIZE IQ test
Score from a NEW IQ test
Relationship
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Scatter Plots Showing Different RelationshipsScatter Plots Showing Different Relationships
Positive RelationshipPositive Relationship Negative RelationshipNegative Relationship
No Consistent RelationshipNo Consistent Relationship13/04/23 19
Predictive ValidityPredictive Validity
• Theories predict how difference values of a construct affect behavior
• The measurement of a construct accurately predict according to the theory
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Construct Validity
• The demonstrate that measurements of a specific variable behave in exactly the same way as the past research
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Convergent and Divergent ValidityConvergent and Divergent Validity
• Convergent Validity Convergent Validity is demonstrated by a strong relationship between the scores obtains from two difference methods of measuring the same construct
• Divergent Validity Divergent Validity is demonstrated by using two different methods to measure two different constructs. Then there should be little or no relationship between the scores
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Validity and and Reliability of Measurement
• Validity of Measurement
• Definitions of Validity
• Reliability of Measurement– Type and Measures of Reliability
• The Relationship Between Reliability and Validity
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Reliability of MeasurementReliability of Measurement
• The second criterion for evaluating the quality of a measurement procedure
• Reliability Reliability : Repeatedly to measure the same individual under the same condition, should nearly
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Concept of ReliabilityConcept of Reliability
Measured Score = True Score + Error
Should Should average average to ZEROto ZERO
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Sources of ErrorSources of Error
• Observer Error
• Environment Error
• Participant Error
IQ test
example Test of intelligenceexample Test of intelligence
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Type and Measures of ReliabilityType and Measures of Reliability
• Successive measurementSuccessive measurement
• Simultaneous measurementSimultaneous measurement
• Internal consistencyInternal consistency
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Type and Measures of ReliabilityType and Measures of Reliability
• Successive measurementSuccessive measurement• A researcher may use exactly the same
measurement procedure for the same group of individuals at two different times
• Called Test - Retest reliabilityTest - Retest reliability
• Simultaneous measurementSimultaneous measurement• Measurements are obtained by direct observation
of behaviors, it is common to use two or more separate observers who simultaneously record measurement
• Called inter-rater reliabilityinter-rater reliability13/04/23 28
Type and Measures of ReliabilityType and Measures of Reliability
• Successive measurement
• Simultaneous measurement
• Internal consistencyInternal consistency• General process results : Split-half reliability
Example :Example :
1. Use multiple-exams to measure performance in an academic course
2. Splitting the exams in half
3. Then calculating the degree of consistency between the two scores for a group of participants
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The Relationship Between Reliability The Relationship Between Reliability and Validityand Validity
• Both Both : Criteria for evaluation the quality Criteria for evaluation the quality measurement proceduremeasurement procedure
• Partially related and Partially independentPartially related and Partially independent– Related : Reliability is a prerequisite for Reliability is a prerequisite for
validityvalidity– independent : Not necessary for a Not necessary for a
measure to be valid for to be reliablemeasure to be valid for to be reliable
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OutlineOutline
• An Overview of MeasurementAn Overview of Measurement• Constructs and Operational DefinitionsConstructs and Operational Definitions• Validity and Reliability of MeasurementValidity and Reliability of Measurement• Scales of MeasurementScales of Measurement• Modalities of MeasurementModalities of Measurement• Other Aspects of MeasurementOther Aspects of Measurement
13/04/23 31To be Continue