2.2 Basic and Developmental Research Designs

Descriptive, Case Study, Ethnographic Studies, Correlational Study, Experiment & Quasi-Experiment

Basic Research Designs

Descriptive

Design that aims to observe and record behavior Case Study

Useful in rare cases

Advantages of Case Study

Cannot generalize data, cannot make strong causal statements, and has low external validity

Disadvantages of Case Study

Ethnographic Studies

Seeks to describe the pattern of relationships. Customs, beliefs, technology, arts, and traditions that make up a society’s way of life

Helps overcome cultural biases & debunks Western-developed theories

Advantages of Ethnographic Studies

Open to observer bias

Disadvantages of Ethnographic Studies

Correlational Study

Study that examines the relationship between two or more variables

Determines the strength and direction of an association & has high external validity

Advantages of Correlational Studies

Does no establish causal links & no random assignment

Disadvantages of Correlational Studies

Experiment

Study that establishes cause-and-effect relationships between variables

Permits replication & high internal validity

Advantages of Experiments

Possible ethical issues

Disadvantages of Experiments

Quasi-Experiment – Design that tests cause-and-effect relationships but with no random assignment

Cross-Sectional Design, Longitudinal Design, & Sequential Design

Developmental Research Designs

Longitudinal Design

Follows the same group of individuals over an extended period, measuring their characteristics or behaviors at multiple time points

Cross-Sectional Design

This design compares different age groups at a single point in time

Less time-consuming and provides immediate information about age-related differences with multiple age groups simultaneously

Advantages of Cross-Sectional Design

Cannot determine how individuals change over time

Disadvantages of Cross-Sectional Design

Cohort Effects

Cross-sectional design is vulnerable to this effect in which differences between age groups may be due to unique experiences of their generation (cohort) rather than actual developmental changes

Longitudinal Design

Follows the same group of individuals over an extended period, measuring their characteristics or behaviors at multiple time points

Can directly measure individual developmental changes, eliminates cohort effects, can examine stability of traits and impact of early experiences on development

Advantages of Longitudinal Design

Time-consuming, expensive, practice effects, & prone to time-of-measurement effects

Disadvantages of Longitudinal Design

Practice Effects

Longitudinal design is prone to this effect in which participants may perform differently on repeated measures due to familiarity with the tests

Participant’s Attrition

Individuals in longitudinal designs may drop out of the study over time, potentially leading to a biased sample

Sequential Design

Design that combines elements of both cross-sectional and longitudinal approaches

Can separate age effects from cohort effects, Provides information about age-related changes between individuals and age-related differences between groups, more efficient than longitudinal in terms time and resources

Advantages of Sequential Design

Still susceptible to some attrition and practice effects, may not completely disentangle all developmental influences

Disadvantages of Sequential Design