Chapter Three: Research Methods

Variable

A characteristic that varies from individual to individual.

Mediation

A method used to compare the correlation between two variables with and without their joint correlation to a third variable.

Most Efficient Design

A set of 3 designs manipulating the variables of age, cohort, and time of measurement.

Multiple Regression Analysis

A set of variables is used to predict scores on another variable.

Latent Variable

A statistical composite of several variables, that were actually measured.

Longitudinal Design

People are followed repeatedly from one test occasion to another.

Case Report

Provides in depth data from a relatively small number of individuals.

Descriptive Research Design

Provides information about age differences but does not attempt to rule out social or historical factors.

Experimental Design

Research method in which an independent variable is manipulated and scores are then measured on the dependent variable. Involves random assignment of respondents to treatment and control groups.

Daily Diary Method

Research method in which participants enter data on a daily basis about interactions with family, friends, and stress.

Correlational Design

Researchers investigate relationships among two or more variables.

Multivariate Correlational Design

Researchers simultaneously evaluate the effects of more than two variables.

Path Analysis

Researchers test all possible correlations among a set of variables to see if they can be explained by a single model.

Logistic Regression

Researchers test the likelihood of an individual recieving a score on a discrete yes or no variable.

Structural Equation Modeling

SEM. A process where researchers test models involving relationships that include latent variables.

Incidence Statistics

Data that provides estimates of the percent of people who first develop symptoms in a given period.

Prevalence Statistics

Data that provides estimates of the percentage of people who have ever had symptoms in a particular period.

Correlation

Expresses the strength and direction of a relationship between two variables.

Prospective Study

A variant of longitudinal design in which researchers sample from a population of interest before they develop a particular type of illness or experience a particular type of life event.

Survey Method

A way to gain information about a sample that can be generalized to a larger population.

Sequential Designs

Different combinations of the variables of age, cohort, and time of measurement.

Independent Variable

Factor that the researcher manipulates.

Quasi Experimental Design

Groups are compared on predetermined characterisitics.

Cross Sectional Design

Groups of people are compared with different ages at one point in time.

Hierarchical Linear Modeling

HLM. A statistical methodology where researchers study the patterns of change within individuals over time.

Age

How many years (or months) the person has lived.

Cohort Sequential Design

Method in which cohorts are compared at different ages.

Cross Sequential Design

Method in which cohorts are examined at different times of measurement.

Time Sequential Design

Method in which data are organized by age and time of measurement.

Dependent Variable

Outcome that researchers observe.

Epidemiology

Study of the distribution and determinants of health related states or events (including disease).

Selective Attrition

The fact that the people who drop out of a longitudinal study are not necessarily representative of the sample that was originally tested.

Terminal Decline

The gradual loss of cognitive abilities as an individual draws closer to death.

Cohort Effect

The social, historical, and cultural influences that affect people during a particular period of time.

Laboratory Studies

The testing of participants in a systematic fashion using standardized procedures.

Archival Research

When investigators use available records to provide data on the hypothesis they want to test. Use existing resources that contain data relevant to a question about aging.

Qualitative Method

When researchers use a flexible approach to understand the main themes in their data.

Focus Group

When respondents meet together and discuss a particular topic that the researcher assigns to them.

Moderation

When two variables are believed to have a joint influence on a third.

Time of Measurement

Year or period in which a person is tested.

Cohort

Year or period of a person's birth.