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

13/04/23 2

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

13/04/23 3

Aspects of measurementAspects of measurement

• Not a one to one relationship– Variable being measured : Measurements

obtained• Usually several different options for measuring

particular variable

13/04/23 4

ExampleExample

Knowledge for each studentKnowledge for each studentMeasureMeasure

An exam

An essay

A set of problems

Impossible to look inside each student’ head

13/04/23 5

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

13/04/23 6

Constructs And Operational Constructs And Operational DefinitionsDefinitions

• Constructs Definitions

• Operational Definitions

13/04/23 7

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

13/04/23 8

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

13/04/23 9

Example : Operational Definitions Example : Operational Definitions

Intelligence IQ

Hunger ?Hunger ?

13/04/23 10

Using Operational DefinitionsUsing Operational Definitions

A research study A research study areare

hypothetical constructshypothetical constructs

13/04/23 11

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 12

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

13/04/23 13

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.

13/04/23 14

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

13/04/23 15

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

13/04/23 16

Concurrent ValidityConcurrent Validity

• The scores obtained from the new measurement technique are directly related to the scores obtained from another

13/04/23 17

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

13/04/23 18

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

13/04/23 20

Construct Validity

• The demonstrate that measurements of a specific variable behave in exactly the same way as the past research

13/04/23 21

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

13/04/23 22

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

13/04/23 23

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

13/04/23 24

Concept of ReliabilityConcept of Reliability

Measured Score = True Score + Error

Should Should average average to ZEROto ZERO

13/04/23 25

Sources of ErrorSources of Error

• Observer Error

• Environment Error

• Participant Error

IQ test

example Test of intelligenceexample Test of intelligence

13/04/23 26

Type and Measures of ReliabilityType and Measures of Reliability

• Successive measurementSuccessive measurement

• Simultaneous measurementSimultaneous measurement

• Internal consistencyInternal consistency

13/04/23 27

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

13/04/23 29

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

13/04/23 30

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