Overview- Lecture 4 Research Methods Research Designs: Review of the Basics Developmental Research Designs Measurement Effects: Confounds Better Ways? Psychometrics

Overview- Lecture 4 Research Methods Research Designs: Review of the Basics Developmental Research Designs Measurement Effects: Confounds Better Ways? Psychometrics

Simple Correlational Designs Two variablesTwo variables Statistic can range from -1 to +1Statistic can range from -1 to +1 Cannot infer cause-effect relationshipsCannot infer cause-effect relationships Basic Concepts

Simple correlation - Positive Simple correlation - Positive Age Reactiontime Basic Concepts

Age Depression Simple correlation - Negative Simple correlation - Negative Basic Concepts

Variable Independent Experimental Designs Dependent Design Basics Variable that is manipulatedVariable that is manipulated Variable that is observedVariable that is observed Characteristic along which people differCharacteristic along which people differ

Manipulation of independent variableManipulation of independent variable Respondents randomly assigned to groupsRespondents randomly assigned to groups Determine cause and effectDetermine cause and effect Compare groups on predetermined characteristicCompare groups on predetermined characteristic Cannot draw cause and effect conclusionsCannot draw cause and effect conclusions Used in most studies of agingUsed in most studies of aging Experimental Designs Experimental design Quasi-experimental design

Overview- Lecture 4 Research Methods Research Designs: Review of the Basics Developmental Research Designs Measurement Effects: Confounds Better Ways? Psychometrics

Developmental Research Designs Cross-Sectional Design Longitudinal Design Basic Designs

yrs.60 yrs.70 yrs.80 yrs. 40 yrs. 60 yrs. 50 yrs. 70 yrs. 30 yrs. Year of test Year of birth Cross-sectional Design

yrs.60 yrs.70 yrs.80 yrs. 40 yrs. 60 yrs. 50 yrs. 70 yrs. 30 yrs. Year of test Year of birth Longitudinal Design

Overview- Lecture 4 Research Methods Research Designs: Review of the Basics Developmental Research Designs Measurement Effects: Confounds Better Ways? Psychometrics

Measurement Effects: Confounds Age Cohort Time of measurement Effects Chronological age, measured in years Year or period of birth Time of testing Term Definition Index of: Change within individual Influences relevant to history Current influences

Longitudinal Seem to measure age “changes” but.. ConfoundDesign Cross-Sectional Basic problem: Cannot separate “age” from “time” Measurement Effects: Confounds Age effects cannot be separated from historical change Measures age group differences because… Age effects may be due to cohort differences

Overview- Lecture 4 Research Methods Research Designs: Review of the Basics Developmental Research Designs Measurement Effects: Confounds Better Ways? Psychometrics

Better Ways? Sequential Research Designs (Shaie’s Designs) Involve a “sequence” of designs Allow inferences to be made about age effects and historical influences (cohort effects and time of measurement/test year effects)

Time sequential Age Factor 2 Cohort sequential Design Factor 1 Test Year Cross sequential CohortAge CohortTest year Sequential Research Designs: Schaie’s “Most Efficient Design” Comparison of Designs

yrs. 60 yrs.70 yrs.80 yrs. 40 yrs. 60 yrs. 50 yrs. 70 yrs. 30 yrs. Cross-Sectional Sequences Alternative Sequential Designs (Baltes) Year of test Year of birth

yrs. 60 yrs. 70 yrs. 80 yrs. 40 yrs. 60 yrs. 50 yrs. 70 yrs. 30 yrs. Longitudinal Sequences Alternative Sequential Designs (Baltes) Year of test Year of birth

Correlational Approaches: Multivariate Correlational Designs Multiple variables Causal relationships estimated

Types Predictor variables used to estimate dependent variablePredictor variables used to estimate dependent variable Can suggest and test causal relationshipsCan suggest and test causal relationships Multiple regression analysis Diagram a set of relationshipsDiagram a set of relationships Test data against hypothesized modelTest data against hypothesized model Structural equations Correlational Approaches in Research on Aging: Multivariate Correlational Designs

Correlational Approaches in Research on Aging: Multivariate Correlational Designs See text page 68

Overview- Lecture 4 Research Methods Research Designs: Review of the Basics Developmental Research Designs Measurement Effects: Confounds Better Ways? Psychometrics

Measurement Issues: Psychometrics Forms of reliability Forms of validity Test-retest Internal consistency Content Construct Criterion Give test on two occasions Test items yield similar answers Test measures what it is supposed to measure Test gives consistent responses Factual content measured correctly Scores fit with theory Scores predict actual performance Need to be established on all age groups tested Psychometrics