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.
