Research design
- Blueprint for conducting a study
- Purpose, review of literature, and framework provide the basis for the design
Types of Research Design
- Descriptive
- Correlational
- Quasi-experimental
- Experimental
Descriptive Design
- Exploration and description of phenomena in real-life situations
- New meaning is discovered, and the description of concepts if accomplished
- Helps to identify relationships
Correlational Design
- Looks at the relationship between two or more variables
- Determines the strength and type of the relationship
- Explains what is seen
- No cause and effect
Quasi-experimental Design
- Examines cause and effect relationships
- Less control by a researcher than true experimental designs
- Samples are not randomly selected
- All variables in the study cannot be controlled by the researcher
Experimental Design
- Controlled manipulation of at least one independent variable
- Uses experimental and control groups
- Random assignment of the sample to the experimental and control groups
Cross-Sectional vs. Longitudinal Design
CSD: Involves data collection on variables at one point in time ( various levels of education, development, illness, etc.)
LD: Involves data collection from same study participants at multiple points in time, might also be referred as repeated measures.
Internal Validity
Validity is focused on determining if study findings are accurate
Threats to Design Validity:
- Participant selection
- Participant attrition
- History
- Maturation
External Validity
Validity is concerned with the extent to which study findings can be generalized beyond the sample used in the study.
Threats to Design Validity
- Participant selection (people)
- Setting (place)
- History (time)
Experimental Group vs. Comparison Group
EG: Group of participants who received study intervention
CG: Group that is not exposed to the intervention
Randomized Controlled Trial (RCT)
The design uses large number of subjects to test a treatment’s effect and compare results with a control group who did not receive the treatment.
- Subjects come from a reference population and are randomized
- Usually, multiple geographic locations are used.
Causality
Examines the effect of a particular intervention on selected outcomes
Multicausality
Particular outcome. The recognition that several interrelating variables can be involved in causing a ome. The presence of multiple causes for an effect.
Probability
Addresses relative rather than absolute causality.
Bias
Distortion of study findings that are slanted or deviated from the true or expected.
Control
The power to direct or manipulates factors to achieve a desired outcome. This is greater in experimental than quasi-experimental designs
Manipulation
A form of control generally used in quasi-experimental and experimental studies.
