Transcript Establishing the Research Design

Writing a Research Protocol
Michael Aronica MD
Program Director
Internal Medicine-Pediatrics
Assumptions
You already have a research question or
problem
 Have already searched, read and critically
appraised the literature
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Research Protocol Outline
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Title
Purpose
Introduction
Hypothesis
Setting(s)
Subjects
External Validity
Design
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Dependent Variable
Independent Variables
Operational
Hypothesis
Data Collection
Sample Size
Data Analysis
Time Table
Budget
PICO
Patients
 Intervention
 Comparison
 Outcome(s)
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Title
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Accurate
Relevant
Succinct
Use your PICO framing to make specific
Purpose
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A general statement of the purpose of the research
A series of specific aims
– To describe….
– To compare…
– To determine to effect of…
Introduction
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Briefly justify the study in terms of existing information
and the importance of the question.
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3 paragraphs
– Why is topic important?
» Why should I care; hook
– What are the gaps in the literature?
» Transition: the gap you will address
– What is your study purpose?
» Can include hypotheses or questions
Hypothesis
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Rephrase the purpose of the study in terms of the existing
information and the importance of the question.
– Specific “If-Then statement.
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A statement about the relationship between two variables
that is designed to answer a research question. Identify the
direction of the relationship using terms such as greater
than, less than, positively, or negatively.
– The strength of a person’s spiritual convictions is positively related
to their health
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The second feature of a research hypothesis is that it must
be testable. Essentially, hypotheses testing the relationship
between variables requires observation, measurement, and
analysis.
– Valid indicators would be needed for measuring spiritual
convictions and health.
Outline for a Research Protocol
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Settings
– Where will the research be done?
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Subjects
– Who will be in the study?
– Inclusion Criteria: characteristics of potential subjects
that contribute to the success of a study.
– Exclusion Criteria: characteristics of potential subjects
that may confuse, confound or invalidate results. By
eliminating these subjects, the researcher can control
some of the variability.
External Validity
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To whom will your findings be generalizable?
The degree to which your sample’s findings will
hold true to which population.
Design
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Study design you have chosen to use
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Experimental
Cohort
Cross-sectional
Case-control study
Include some discussion to show that this is the
preferred design for your purpose.
Dependent Variable
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Usually the health outcome(s) that you are
studying
What type of variable
– Continuous
– Catagorical/dichotomous
Independent Variables
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Risk factors, casual factors, experimental treatment, and
other relevant factors
Potential confounders
– Age
– Gender
– Race
– SES
– Severity of Illness
Determined by literature search or experts
Operational Hypothesis
Rephrase the purpose of the study as a
series of comparative questions
 Usually a statistical hypothesis
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– Eg. The mean bone density loss is greater in
adolescents on Depo-Provera that those on
BCP’s
– ‘Mean loss’ operationalizes decreased bone
density
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Different from the null hypothesis
Data Collection
How and by whom?
 Prepare detailed protocol so that every step
can be easily replicated by someone else.
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– Physiological or Biological Measurement
– Observational Methods
– Interviews and Questionnaires
» scripts for structured interviews
» formally constructed questionnaires
– Records or available data
Data Collection
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Include sample questionnaires or other data collection
forms (instruments)
For Quantitative studies:
– the measures should be objective
– approach should be systematic
» same questions or data in the same order
Two properties of instruments are important
– Validity: how well do the data reflect reality?
– Reliability: how well do results compare if the instrument
is applied more than once?
Sample Size
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Calculations and the assumptions on which they are made.
– Alpha: the probability of a Type I error.
» Usually set at .05
» Alpha errors are like false alarms: you think you’re on to something,
but you’re really not. your result is a false positive
– Beta: the probability of a Type II error.
» Usually set at .2
» Beta errors are false negatives; there really is an effect in the real
world, but the study missed it.
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Also need to know the baseline characteristic of your
sample (eg prevalence) and the clinically significant
change you are trying to measure
Online power calculators
Data Analysis
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Outline a strategy for analysis
A detailed list of statistical procedures is not necessary.
– Parametric vs non-parametric
– Continuous outcomes vs dichotomous outcomes
– Continuous variables va categorical variables
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Your strategy should indicate how you will test each
operational hypothesis.
Discuss confounding and any other means for controlling
bias.
– Stratifying
– Regression
Time Table
Plan for accomplishing each step of the
study
 Help to organize the structure of a research
program
 Can assist in keeping on schedule and
avoiding “costly” delays
 Are especially important in residency-based
research due to deadlines
 Present in table format
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Time Table
Task
Recruitment of Participants
Demographic Data, Consents
Revision of Surveillance Protocols
Programming Zoomerang Protocols
Surveillance Protocol #1
Surveillance Protocol #2
Obtain WISCP participation data
Combined Data Analysis
Organize Post-hoc Surveillance Meeting
Meeting to Discuss Surveillance
Writing Final Report
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Budget
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Not necessary for IRB submissions
Will be needed for institutional or other grants
Know what the award is for and what are the
constraints.