1. Research Design for Quantitative Studies

2. Characteristics of Well Designed Research
Clearly defined research question
Clearly defined population under study
Clearly defined sampling procedure
Clearly defined variables of interest
Clearly defined statistical method
Statement of the null hypothesis, Ho:
Statement of the alternative hypothesis, Ha:
Collection of sample under appropriate conditions
Analysis and report

3. Research Design Overall plan answer research questions
test research hypotheses

4. Dimensions of Research Design
Intervention
Comparisons
Controls for extraneous variables
Timing of data collection
Research setting
Communication with subjects

5. Types of Research Design
Experimental Research
Quasi Experimental Research
Nonexperimental Research

6. Experimental Research
Manipulation
Control
Randomization

7. Experimental Designs Basic Solomon Four-Group Factorial
Repeated Measures
Clinical Trials

8. Basic Experimental Designs
Posttest-only
Pretest-Posttest
R=Randomization M=Measurement X=Treatment
R X M-2
R M-1 X M-2

9. Solomon Four-Group Design
Data Collection
Group Before After
Experiment-pretest X X
Experiment-no pretest X
Control-pretest X X
Control-no pretest X

10. Factorial Design
Permits the testing of multiple hypotheses in a single experiment
Permit evaluation of main effects as well as interaction effects
Subjects randomly assigned to some combination of treatments
Independent variables known as factors
Each factor has two or more levels

11. Factorial Design Type of Stimulation Auditory(A1) Tactile (A2)
15 min (B1) A1 B1 A2 B1
30 Min (B2) A1 B2 A2 B2
45 Min (B3) A1 B3 A2 B3

12. Repeated Measures Design
Also known as crossover design
Exposure of same subjects to more than one experimental treatment
Participants must be randomly assigned to different orderings of treatment
Ensures highest possible equivalence among subjects exposed to different conditions
May have carry-over effects

13. Randomized Clinical Trials
Distinctive application of experimental design
Involves testing of clinical treatment
Random assignment of subjects
Focused on outcomes
Large and heterogenous sample

14. Advantages of Experimental Research
Powerful method of testing cause-effect relationships

15. Disadvantages of Experimental Research
Many variables not amenable to experimental manipulation
Ethical considerations may prevent experimental manipulation
May be impractical
Hawthorne (placebo) effect

16. Quasi-Experimental Research
Involves manipulation of independent variable
Lacks either or both
Randomization
Control Group

17. Quasi-Experimental Designs
Non-equivalent control group design
Time series design

18. Nonequivalent Control Group Designs
Involves experimental treatment and two or more groups of subjects
Comparison group rather than control group
Quasi-experimental versus pre-experimental

19. Time Series Designs One Group
Data collection over extended time period
Experimental treatment during course of data collection

20. Advantages and Disadvantages of Quasi-Experimental Design
Practical and feasible
Cannot make cause-effect inferences

21. Nonexperimental Research
No manipulative control of independent variables

22. Non-Experimental Designs
Ex Post Facto/Correlational research
Retrospective studies
Prospective studies
Descriptive research

23. Advantages and Disadvantages of Non-experimental Research
Cannot infer causal relationships
Efficient means of collecting large amounts of data about problem
Realistic

24. Additional Types of Quantitative Research
Survey
Evaluation
Needs Assessment
Outcomes
Meta-analysis

25. Techniques of Research Control
External factors
constancy of conditions
protocols

26. Techniques or Research Control
Intrinsic factors
Randomization
Homogeneity
Blocking
Matching
Statistical control

27. Threats to Internal Validity
History
Testing
Instrumentation
Selection
Maturation
Mortality

28. External Validity
Generalizability of results
Validity
Reliability

29. Threats to External Validity
Hawthorne effect
Novelty effect
Interaction of history and treatment effect
Experimenter effect
Measurement effect

30. Nursing Studies Are---
Usually nonexperimental
Most commonly use correlational design
More often retrospective than prospective
More likely to use analysis of covariance and similar techniques to control intrinsic factors
Typically limited in terms of external validity

31. Tips for Enhancing Research Conrol
Strategies to control external factors
Maximize constancy of conditions
Strategies to control study participants
Strong research design
Measurement of demographic variables
Identify extraneous variables via review of literature