Non-Experimental Design Overview

Definition: Non-experimental design refers to research methods that do not involve the manipulation of independent variables. There are no controlled experiments, and conditions are not artificially created.
Characteristics:
- Lacks random assignment to groups.
- Involves studying preexisting groups (e.g., age groups, schools, etc.).
- Attempts to observe and analyze existing relationships or differences without intervention.
Internal Validity Threats:
- Internal validity refers to the extent to which a causal conclusion based on a study is warranted. In non-experimental designs, threats to internal validity include:
- Confounding Variables: Other variables that may influence the results.
- Selection Bias: Preexisting differences among groups that may affect outcomes.
- Historical Effects: Events occurring during the study that could impact results.
Common Types of Non-Experimental Designs:
- Observational studies: Observing subjects in a natural setting without manipulation.
- Correlational studies: Analyzing the relationship between two or more variables without manipulation.
- Case studies: In-depth examination of a single subject or group over an extended period.
Limitations:
- Results may be less generalizable due to the lack of experimental controls.
- Difficult to establish causation due to the absence of randomization and manipulation.
- More susceptible to biases and external influences, which can skew results.