Quantitative research designs in research ug

Quantitative research designs in research ug

1. College of Education
School of Continuing and Distance Education
2014/2015 –2016/2017
NURS 345
NURSING RESEARCH
Session 8 –Quantitative Research Designs
Lecturer: Dr. Florence Naab
Contact Information: [email protected]

2. Session Overview
•Some research problems are better explained using numbers.
It is only through quantitative designs that these numbers can
be generated and interpreted. This session discusses
quantitative research designs. By the end of this session,
students will be able to:
1.Describe and explain experimental and quasi-experimental designs
2.Differentiate between experimental and non-experimental designs
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3. Session Outline
The key topics to be covered in the session are as follows:
Topic one: Experimental designs
Topic two: Quasi-experimental design
Topic three: Non-experimental designs
Slide 3

4. Reading List
Chapter 9 of;
Nieswiadomy, R.M (2008). Foundations of Nursing Research.
5th Ed. Pearson Education, USA.
Chapter 9 of;
Creswell, J. W. (2003). Research Design: Qualitative,
quantitative, Mixed Methods Approaches.2
nd
Ed. Sage
Publications
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5. EXPERIMENTAL DESIGNS
Topic One
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6. What is an experimental design?
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7. Experimental design
Is a design in which one or more variables are manipulated
(independent variable) to see their effect on other variables
(dependent variable).
The researcher is an active agent in the research because of
the experimental treatment involved.
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8. Characteristics of experimental
designs
Every experimental design has three main
characteristic;
1.Manipulation: In experimental research, the
experiments often involve two groups
(experimental and control groups). In manipulation,
the researcher does something to some of the
participants in one group.
2.Control:The researcher holds constant the
experimental situation in one group of participants.
3.Randomization: The researcher assigns participants
to the group randomly. This is to ensure that every
participant has an equal chance of being assigned
to any group.
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9. Types of experimental designs
Basic experimental designs
Solomon four-group design
Factorial design
Repeated measures design
Randomized clinical trials
Note: Each of these will be explained in subsequent
slides.
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10. Basic experimental designs
•Basic experimental designs are less complicated.
However, because there is an experiment involved,
careful selection of these participants is very
important.
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11. Types of basic designs
1.After-only or post-test only design.
2.Before-after or pretest-posttest design.
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12. After-only/post-test only design
In this type of design, there is no data collection prior
to the experiment.
Data is only collected once after the experimental
treatment has been given.
Note: See an example in the next slide
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13. Slide 13

14. Before-after/pretest-posttest design
Is a design with two data collection points.
The initial data collection point is called a baseline
measure.
The second data collection point is after the
researcher gives the experiment. Sometimes referred
to as the outcome measure.
NOTE: See example in the next slight
Slide 14

15. Slide 15

16. Solomon four-group design
This design consist of two experimental and two
control groups
One experimental group and one control group will
not be given the pre-test.
All four groups will be given the post-test
NOTE: See example on next slide
Slide 16

17. Slide 17

18. Factorial design
This design involves multiple independent variables
that are systematically manipulated in a single
experiment
The design allows the researcher to evaluate both
the main and interaction effect of the experiment
NOTE: See example on next slide
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19. Factorial design
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20. Repeated measures
This design is also known as cross-over design.
It involves the exposure of the same participants to
more than one experimental treatment.
It has a disadvantage of carry over effect
NOTE: See example on next slide
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21. Slide 21

22. Randomized clinical trials (RCT)
RCT involves the testing of a clinical treatment.
Participants are randomly assigned to the
experimental and control groups.
Data is collected on the outcome of the treatment.
NOTE: See example on next slide
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23. Slide 23

24. QUASI EXPERIMENTAL DESIGNS
Topic Two
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25. What are quasi experimental designs?
Slide 25

26. Quasi-experimental designs
Refers to designs that are almost experimental.
Involves manipulation of an independent variable but lacks
randomization or a control group.
NOTE: See example in the next slide
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27. Slide 27

28. Type of quasi-experimental designs
1.Nonequivalent control group design.
2.Time series design
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29. Non-equivalent control group design
Involves an experimental treatment and two or more
groups of participants.
There is no random assignment of participants to
groups.
Note: See example on next slide
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30. Slide 30

31. Time series design
This design is also known
as interrupted time series
design.
Involves the collection of
data over an extended
period and the
introduction of an
experimental treatment
during the course of data
collection period.
Lacks randomization and
control group
Example
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32. NON-EXPERIMENTAL DESIGNS
Topic Three
Slide 32

33. What are non-experimental designs?
Slide 33

34. Non-experimental design
Designs in which the independent variable cannot be
manipulated.
Most nursing investigations are non-experimental.
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35. Reasons for using non-experimental
designs
Many human characteristics cannot be
experimentally manipulated e.gblood type and
health beliefs.
Manipulating human characteristics such as behavior
is unethical.
Constraints such as lack of time makes experiments
impossible.
Experimental design may not be appropriate for
some research.
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36. Types of non-experimental designs
Ex post facto or correlationaldesign
Descriptive design
Survey design
Evaluation research
Outcome research
Cross sectional
Longitudinal
NOTE: Each of the above will be explained in
subsequent slides.
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37. Ex post facto or correlationaldesign
The research is conducted after variations in the
independent variable have occurred in a natural
course of events.
Designed to understand relationships among
variables as they naturally occur without a
researcher’s intervention.
The researcher does not have control over the
independent variable because it has already
occurred.
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38. Descriptive design
The purpose is to describe, observe, and document
aspects of a situation under investigation.
No experimental manipulation or random
assignment to groups.
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39. Survey design
Designed to obtain
information from
populations regarding the
prevalence, distribution,
and interrelations of
variables within the
population studied.
Data is based on self-
report.
Surveys may be cross-
sectional or longitudinal
Survey data gathering is by:
1.Personal interviews
2.Telephone interviews
3.Questionnaire
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40. Evaluation research
Involves finding out how well a programme, practice,
procedure, or policy is working.
Focuses on an appraisal of a specific new
intervention.
Primary purpose is to assess or evaluate success of
an instituted policy or programme.
The researcher investigates issues that are
organizational, interpersonal, or political in nature.
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41. Outcome research design
Designed to investigate the effectiveness of an
implemented programmeor service.
The primary purpose is to assess the quality of a
programmeor health services.
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42. Cross sectional design
Involves a one time collection of data.
The phenomena under study are captured during
one period of data collection.
Are appropriate for describing relationships between
variables at a fixed point in time.
Are relatively economical.
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43. Longitudinal designs
Involves data collection at more than one point in
time over an extended period of time.
Used to study time related processes, i.ephenomena
that evolve over time.
Used to make comparisons over time.
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44. Summary and conclusion
•This session has discussed experimental, quasi-
experimental, and non-experimental designs used in
nursing research.
•The next session will discuss population and
sampling.
Slide 44

45. References
Creswell, J. W. (2003). Research Design: Qualitative,
quantitative, Mixed Methods Approaches.2
nd
Ed. Sage
Publications
Nieswiadomy, R.M (2008). Foundations of Nursing Research.
5th Ed. Pearson Education, USA.
Polit, D. F. and Beck, C.T (2008). Nursing Research: Generating
and Assessing Evidence for Nursing Practice. 8th Ed.
Lippincott Williams & Wilkins, USA.
Robsin, C. (2002). Real World Research: A Resource for Social
Scientist and Practitioner-Researchers. 2nd Ed. ISBN,
USA.
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