Transcript Design

Research Methodologies in
Allied Health
Mary C. Haven, MS
Associate Dean,
SAHP
1
This is how Hubert does research!
He jumps right in.
2
Objectives
After lecture, reading Section 3 in your text,
discussion, and class participation, the
student will be able to:
 Compare and contrast at least four
research designs.
 Given a simple research question, adapt it
to a specific research design and explain
why this design was chosen.
3
Objectives
 Determine a control group for a
research question.
 Select a way to randomize research
subjects into experimental or
control.
4
Experimental Design
Researcher
 Manipulates the independent variable
 Observes the effects of this
manipulation on the dependent
variable
 Measure the effect on the dependent
variable
5
Experimental Design
Dependent variable will be altered by
manipulation of the independent
variable.
6
True Experimental Method
Manipulation
Control
Randomization
7
Control Group
A group of subjects that experiences the
same day-to-day occurrences and
influences as the experimental group
but does not receive the study
treatment.
8
Why am I always
picked for the placebo
and/or control group?
9
Randomization
A random selection
means that every
subject in the
population
concerned has an
equal chance of
being selected for
the study sample.
10
Table E.l RANDOM NUMBERS
Appendix E
Statistical Tables
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Experimental Method
Pre-Test/Post-Test Design
1. Hypothesis
2. Select experimental and control groups by
randomization.
3. Do pre-test.
4. Manipulate experimental group.
5. Do post-test.
6. Analyze results.
7. Accept or reject hypothesis.
R
O
R
O
X
O
O
12
Research Design Shorthand
R = Randomization
O = Observation
X = Intervention
13
Example with This Class
This Class
Pre-test
40
30
27
44
32
This Class Control Gr. Control Gr.
Post-test
Pre-test
Post-test
100
40
41
95
50
45
94
96
100
30
22
42
29
35
45
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Another Example
R
R
R
O
O
O
X1 O
X2 O
O
New Treatment
Old Treatment
Placebo
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Experimental Research
The Classic
Design
Follow-Up
Post Test Only
R
R
O
O
R
R
X
O
O
R
R
O
O
X
X
O1
O1
02
02
O
O
16
Solomon Four-Group Design
R
O
R
O
R
R
X
O1
O2
X
O3
O4
17
Cohort Designs
R1 X
O
R1
O
R2
O
R2 X
O
18
Factorial Design
R
X1
R
X1
R
O
X2
O
X2
O
R
O
e.g. where X1 = Diet
X2 = Drug
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Harvard Law:
Under the most
rigorously controlled
conditions of
pressure,
temperature, volume,
humidity, and other
variable, the organism
will do as it damn well
pleases.
20
Rosenthal Effect
What the
researcher
expects is
somehow
conveyed to
others, and
that is the
result found.
21
Hawthorne Effect
Because the
subject is
being
observed,
the subject
changes
behavior.
22
Quasi-Experimental Designs
Lack of Randomization
O
X1
O
O
O
Cohort Designs
O
X
O
O
O
23
Naturalistic Comparison
 Comparison of two
or more groups
 No manipulation
 Dependent
Variables
 Large sample size
 Statistical analysis
 Results may
suggest theory
 Demographics
 Psychosocial
 Biochemical
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Murphy’s Law of Research:
Enough research will tend to support your theory.
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Correlational Design
 Hypotheses or
guiding question
 Literature search
 Select large
random sample
 Take
measurements
 Correlational and
regression
analysis
 Interpret results
 Write conclusion
26
Single Subject Design
AB Design
6
5
Phase A
B
4
Dep.
Var. 3
Phase B
2
1
0
Time
Phase A – taking observations
B – intervention
Phase B – observations after intervention
27
Single Subject Design
ABAB Design
6
5
4
Phase A
Phase A
B
B
Dep. Var.3
2
Phase B
Phase B
1
0
Time
Phase A – taking observations
B – intervention
Phase B – observations after intervention
28
Single Group Time-Series Design
Lack of Control – Single Group TimeSeries Design
O
X
O
O
X
O
O
X
O
Multiple Pre-Tests
O
O
O
O
X
O1
X
O2
X
O3
O4
O5
O6
29
Case Study
 Justify need
 Review literature
 State guiding
question
 Obtain data
 Interpret results
 Generalize to
theory
30
Edington’s Theory:
The number of
different
hypotheses
erected to explain
a given biological
phenomenon is
inversely
proportional to the
available
knowledge.
31
Survey Research






Identify problem
Define population
Define variable
Collect data
Analyze results
Make conclusions
32
Methodological Research
 Examination of
need
 Literature search
 Define variables
 Pilot test
 Discussion of
results
 Application
33
Young’s Law:
All great discoveries
are made by mistake.
Corollary:
The greater the
funding, the longer it
take to make the
mistake.
34
Qualitative Field Research




Disciplined inquiry
Examine personal meanings
Of experiences of individuals
And actions of those individuals
 Results may lead to common themes
35
Questions to Consider
 In the article from the J. of Allied Health
 What was the design of the study?
 Can you draw a diagram of the sequence of
events of the study?
 How many groups of subjects were in the study?
 If there were two or more groups, how did the
subjects get into the different groups?
 Was the method of assigning the subjects to the
different groups bias-free?
36