Research Design

Question 1

Why is research design important?

Answer 1

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?”

Question 2

Observational vs. Experimental

Answer 2

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

Question 3

Cross sectional

Answer 3

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

Question 4

Longitudinal

Answer 4

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

Question 5

Cross-sectional design: single group

Answer 5

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?

Question 6

Cross-sectional design: multiple groups

Answer 6

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?

Question 7

Retrospective design

Answer 7

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?

Question 8

Prospective design

Answer 8

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?

Question 9

Case control study

Answer 9

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?

Question 10

Randomised controlled trial

Answer 10

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?

Question 11

Time

Answer 11

Past- Retrospective cohort study
Case control study

present-
cross-sectional study
Retrospective cohort study
Case control study

Question 12

Quasi-experimental design

Answer 12

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

Question 13

Feasibility and pilot studies

Answer 13

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

Question 15

Is there an ideal study design?

Answer 15

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

Question 16

Scientific considerations and generalisability of research

Answer 16

title

Question 17

Conflict of interest:

Answer 17

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

Question 18

researcher bias

Answer 18

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

Question 19

Why is conflict of interest a problem?

Answer 19

industry may influence the design, analyses, and results of studies for financial gain
(e.g., due to increased sales of the product due to favourable findings)
It can compromise the ability of researchers to conduct research and analyse and
report the results in an accurate and impartial manner

Question 20

Does this mean researchers and industry can never work together?

Answer 20

No: lots of high-quality research is funded by industry in partnership with
academics and conducted in an impartial manner.
Researchers are required to be transparent about funding sources and any
potential conflicts of interest.
Researchers reveal potential conflicts of interest that could affect the integrity of
their research when they submit their results for publication in scientific journals.

Question 21

Types of bias in research

Answer 21

heading

Question 22

researcher bias

Answer 22

definition-Any factor (e.g., gifts from the product
manufacturer) that might influence the
researcher to favour certain results

impact on report outcome- Study may be designed so that increases the chance
of finding favorable results. Outcomes are not
accurate or representative of the data.

Question 23

selection bias

Answer 23

definition- individuals or groups recruited, or the data used in analyses, are selected in a way
that is not random.

impact on report outcome-study participants do not represent the population limiting generalizability. Selecting/excluding data
could change the direction/magnitude of the results

Question 24

self report bias

Answer 24

definition- error introduced with self-report data

impact on report outcome- Prevents accurate assessment of relationships between variables

Question 25

recall bias

Answer 25

definition-differences in the ability of participants to accurately recall the variable being
measured (e.g., physical activity level).

impact on report outcome- Erroneous (incorrect) conclusions made; data from one group could be more accurate than another; very relevant to case-control studies

Question 26

reporting bias-

Answer 26

definition-differences between reported and unreported journals

impact on report outcome- Selective reporting of positive, favorable outcomes. Results do not represent the full set of data collected

Question 27

publication bias-

Answer 27

definition- tendency for journals to publish studies with positive results

impact on reported outcome- lack of transparency. Not reporting negative findings
leads to ineffective or harmful interventions or drugs

Question 28

confounding

Answer 28

definition-Error or inaccuracy in the effect of an
exposure on an outcome due to the
influence of another factor

impact on report outcome-incorrectly concluding that a given exposure causes
an outcome

Question 29

residual confounding

Answer 29

definition- The error or inaccuracy that remains after controlling for confounding in the design
and/or analysis of a study.

impact on report outcome- incorrectly concluding that a given exposure causes an outcome.

Question 30

Research has shown that research can be biased!

Answer 30

Background: Studies examining the effects of artificially sweetened beverages on weight have
discrepancies in their results and conclusions.
Objectives: To determine whether risk of bias, results, and conclusions of reviews of effects of
artificially sweetened beverage consumption on weight outcomes differ depending on review
sponsorship and authors’ financial conflicts of interest.
Methods: Systematic review of reviews of the effects of artificially sweetened beverages on weight.
Mandrioli et al. 2016. PLoS ONE 11(9): e0162198. doi:10.1371/journal.pone.0162198
Results:
-Artificial sweetener industry sponsored reviews were more likely to have favorable results (3/4)
than non-industry sponsored reviews (1/23), RR: 17.25 (95% CI: 2.34 to 127.29)
-All reviews funded by competitor industries reported unfavorable conclusions (4/4).
-In 42% of the reviews (13/31), authors’ financial conflicts of interest were not disclosed.
-Reviews performed by authors that had a financial conflict of interest with the food industry
were more likely to have favorable conclusions (18/22) than reviews performed by authors
without conflicts of interest (4/9), RR: 7.36 (95% CI: 1.15 to 47.22).

Question 31

Ways to minimize bias in research

Answer 31

Journals enforce disclosure requirements and penalize anyone who does not disclose.
* Prevent industry influencing research design, data analysis, and interpretation of findings.
* Develop more accurate measurements to reduce self-report and recall bias.
* More funding for well-designed, large-scale, long-term RCTs that examine cause and effect
* Improve transparency by:
* Researchers providing access to datasets from studies for re-analysis by other researchers.
* All RCTs must be registered (methods described) and results/data made accessible to all.
* Require journals to publish studies with negative findings.
* Avoid using language implying causation when the results are indicative of associations.
* Support researchers and journalists to work together to help the general public gain a more
complete understanding of what studies are really telling us.

Question 32

An explanation of confounding

Answer 32

You conduct a large observational study and find a positive association
between bacon consumption and increased risk for premature mortality
Residual confounding:
You conduct another large observational study and measure/control for past-year physical
activity levels.
You once again find an association between bacon consumption and increased risk for
premature mortality.
What other confounding factors should you have considered, measured and controlled for?
Can you be sure that bacon consumption is associated with premature mortality?

Question 33

Health inequalities and generalisability

Answer 33

title

Question 34

Health inequalities

Answer 34

the preventable, unfair and unjust differences in health status between groups,
populations or individuals that arise from the unequal distribution of social,
environmental and economic conditions within societies, which determine the risk
of people getting ill, their ability to prevent sickness, or opportunities to take
action and access treatment when ill health occurs.”

Question 35

The 2010 Marmot Review

Answer 35

The 2010 Marmot Review
 ‘Fair Society, Healthy Lives’ – an evidence-based strategy to address social determinants
of health
 Includes conditions in which people are born, grow, live, work and age and which can
lead to health inequalities
 The lower a person’s social and economic status, the poorer their health and the lower
their life expectancy
 Health inequalities arise from complex interactions between:
* Housing
* Income
* Education
* Employment status
* Social isolation
* Disability
* Gender
* Ethnicity

Question 36

Deprivation

Answer 36

“The damaging lack of material benefits considered to be basic necessities in a
society.”

The Index of Multiple Deprivation (IMD)
It is used as an overall relative measure of deprivation in England

Question 37

Deprivation, life expectancy and health inequalities

Answer 37

Has a negative impact on
healthy life expectancy
Increases the risks for
chronic diseases:
-Obesity
-Type 2 diabetes
-Heart disease
-Some cancers
Makes it more difficult to
access healthy options and
to adopt and sustain
healthy lifestyle behaviours

Question 38

Nearly two-thirds (64%) of adults in England are overweight or obese
Health Survey for England 2019

Answer 38

More than 6 out of 10 men are overweight or obese (68%)

6 out of 10 women are overweight or obese (60%)

Question 39

Increased obesity rates in those with lowest household income

Answer 39

Why is this important?
 Obesity and overweight are associated with increased risks for various chronic diseases
 Type 2 Diabetes – over 4.9 million people in the UK
 Cardiovascular Disease - ~7.6 million people in the UK
 Various cancers (13 different types): breast (post-menopausal), bowel, womb, oesophageal,
pancreatic, kidney, liver, upper stomach, gallbladder, ovarian, thyroid, myeloma meningioma

Question 40

Cardiovascular disease

Answer 40

most common among-
 Male, older adults
 Someone with severe mental illness
 South Asian or African Caribbean heritage
 The most deprived communities

Bias and Biology in the UK:
Sex Inequalities in Heart Attack
 Coronary heart disease kills twice as many
women in the UK as breast cancer
 Heart disease considered a “man’s disease”
 Women delay seeking medical help as they
don’t recognise the symptoms
 A woman is 50% more likely to receive the
wrong initial diagnosis for a heart attack
 Women are less likely than men to receive
some treatments

Question 41

Physical activity

Answer 41

People who are more active are less likely to develop chronic diseases including:
– Type 2 diabetes, cardiovascular disease and some cancers
Age (years)

People can be encouraged to become more physically active to
reduce the chance of developing disease
But health inequalities, deprivation, age/sex influence how active
people are…
Different “baseline” and different abilities to become more
active.

Question 42

Why are study samples not always reflective of population diversity?

Answer 42

 Cost, practicalities, convenience (language, willingness, availability, recruitment strategy)
 Lack of diversity in areas where research is conducted
 Research questions are purposively targeted to a limited demographic
 Desire to protect “vulnerable” groups (e.g., older adults, women of child-bearing age, children)
 To optimism positive findings (e.g., testing medicines on young, healthy adults vs. older adults)

Question 43

What are the implications of conducting research with samples that do not reflect population diversity?

Answer 43

 Research findings may not be applicable to those who are under-represented
 Those who are not represented may be deprived of the benefits resulting from the research
 Messages generated from the research can lead to lack of awareness of disease risks
 Findings do not reflect the complex “lived experiences” of diverse populations
 Policies created from research could be harmful to those not represented

Question 44

Is it always necessary to recruit diverse study samples?

Answer 44

 No – this depends on the research question and whether representation matters
 It isn’t necessary if there is no plausible expectation of treatment differences
 If treatment effects or outcomes are expected to be different for various groups:
– A sub-group analysis should be done (quantitative studies)

Question 45

Other scientific considerations

Answer 45

Circadian rhythms

How do circadian rhythms happen and why is this relevant?

helps regulate body temperature, eating and digestion, hormonal activity, and sleep.

Question 46

Behaviour: important pre-measurement controls

Answer 46

Exercise in the 1 hour before a metabolic challenge
influences results
Rynders et al. J Clin Endocrinol Metab 2014. 99: 220-228
Exercise in the 5 days before a metabolic challenge
influences results
Ten insufficiently active adults completed
three trials in a randomised order. Each trial
comprised five consecutive days of 30 min of
exercise either accumulated in three separate
10-min bouts (ACC) after main meals; a
single 30-min bout after dinner (CONT) or a no-exercise control (NOEX)