Research Design Flashcards
Why is research design important?
To provide a framework of methods and techniques
Enables research to be conducted in a structured way
Research design tells us “how” a study is conducted.
Descriptive Research: “What is going on?”
Experimental (or mechanistic) Research: “Why is it going on?”
Observational vs. Experimental
Observational studies:
there is no intervention
Provides information between an ‘exposure’
and an ‘event’ or ‘characteristics’ of
the population
Experimental studies:
involves an intervention:
Allows for the determination of
cause and effect if the study is
designed appropriately
Cross sectional
Cross-Sectional Longitudinal
Assesses a phenomenon at one point in
time
Measures different samples/populations
(or only one sample/population ONCE)
Provides a snapshot of a given point in
time
Examines trends and changes at a
societal/national/international level
E.G. health survey for England
Longitudinal
assess a phenomenon at several points in time
measures the same sample/ population at several points in time
provides information on change at the individual level
examines changes in the same people over time
E.G. lothian birth cohort study
Cross-sectional design: single group
One sample of participants recruited from target population
Information is collected from these people once
Type of research question:
– What are the associations between energy/nutrient
intakes and frailty in older
migrant women in the UK?
Cross-sectional design: multiple groups
Different groups of defined participants are recruited
Information is collected from these people once
Type of research question:
– Are athletes different from non-athletes? Is one patient group different from
another?
Retrospective design
Backward looking: examine data that already exist
Tries to identify factors that predict whether something will happen
(e.g., disease, sports performance)
Type of research question:
– Does meeting the UK physical activity recommendations over a
lifetime have a protective effect against falling in older people?
Prospective design
Forward looking: collects new data, then sometimes, watch/wait
Waits for outcomes (e.g., development of disease, or sporting
performance) and relates this to suspected influencing factors
Type of research question:
What is the relationship between premature mortality and red
meat consumption?
Case control study
Usually retrospective (but not exclusively)
“Cases” have the outcome (e.g., heart disease)
“Controls” do not have the outcome
Type of research question:
What is the association between allotment gardening and
mental well-being?
Randomised controlled trial
Forward looking (prospective)
Participants are randomized into a “control” or “intervention” group
Follows groups over time to determine a difference in outcomes
Type of research question:
– What is the effect of exercise on cognitive impairment in older adults
with mild to moderate dementia?
Time
Past- Retrospective cohort study
Case control study
present-
cross-sectional study
Retrospective cohort study
Case control study
Quasi-experimental design
An intervention study that DOES NOT:
– Randomise participants AND/OR
– Have a control group
Example: Testing the impact of a physical activity intervention on risk for
type 2 diabetes in South Asian adults
– Only one group (e.g., an exercise intervention)
– Without a control group we cannot say with confidence that the
intervention is/is not effective (it could be due to time/season
Measurement phase 1-
time-
(intervention group (exercise intervention or drug)
Measurement phase 2
Feasibility and pilot studies
Feasibility studies:
– Research done before a main study to determine whether the methods are
feasible and acceptable
– “Can this study be done? Can we recruit patients?”
Pilot studies:
– A small-scale study conducted prior to a large-scale experiment to test and
refine procedures
– “Does initial data suggest our method/intervention could work?”
Both are used to inform the design and implementation of large, definitive
randomized controlled trials
Is there an ideal study design?
Each design has a purpose, strengths and weaknesses
Some designs may have more “bias” than others
Other designs are less generalizable to all populations
Important to avoid drawing conclusions that are not consistent with the study
design used
– For example, you can’t make claims of cause and effect from a study
assessing associations
Scientific considerations and generalisability of research
title
Conflict of interest:
A situation in which a person is (or persons are) in a position to
derive personal benefit and unfair advantage from actions or
decisions made in their official capacity
researcher bias
Any factor—such as investment in the product being studied or
gifts from the product manufacturer—that might influence the
researcher to favour certain results