8. Classify each of the following studies as:
A. Experimental
B. Observational cohort
C. Observational case-control
D. Observational cross-sectional
E. Not an analytical or epidemiologic study
1. Representative sample of residents were telephoned and asked how much they
exercise each week and whether they currently have (have ever been
diagnosed with) heart disease.
2. Occurrence of cancer was identified between April 1991 and July 2002 for
50,000 troops who served in the first Gulf War (ended April 1991) and 50,000
troops who served elsewhere during the same period.
3. Persons diagnosed with new-onset Lyme disease were asked how often they
walk through woods, use insect
9. repellant, wear short sleeves and pants, etc. Twice as many patients
without Lyme disease from the same physician’s practice were asked
the same questions, and the responses in the two groups were
compared.
4.Subjects were children enrolled in a health maintenance organization.
At 2 months, each child was randomly given one of two types of a
new vaccine against rotavirus infection. Parents were called by a
nurse two weeks later and asked whether the children had experienced
any of a list of side-effects.
12. • Study design refers to the methods and methodologies used in research to gather the data
needed to explore a specific question.
• Observational study A study design in which the investigators observe and record events
taking place in the study. The subjects are exposed under more natural conditions
• Descriptive study; An observational study that simply describes the distribution of a
characteristic.
• Analytical study; An observational study that describes associations and analyses them for
possible cause and effect.
• Experimental study; the investigator determines through a controlled process the exposure
for each individual (clinical trial) or community (community trial), and then tracks the
individuals or communities over time to detect the effects of the exposure.
• Cohort study; The term used in clinical and epidemiological research to describe a
longitudinal prospective observational study.
In an observational cohort study, subjects are enrolled or grouped on the basis of their
exposure, then are followed to document occurrence of disease. Differences will be in disease
rates between the exposed and
13. unexposed groups. A cohort study is similar in concept to the experimental study. Note that
this differs from an experimental study because, in a cohort study, the investigator observes
rather than determines the participants’ exposure status. After a period of time, the
investigator compares the disease rate in the exposed group with the disease rate in the
unexposed group.
• Longitudinal study; An observational study design in which measurements are made over a
period of time.
• Longitudinal prospective study; An observational study design in which the investigators
follow subjects for future events.
• Case–control study; A type of observational analytical longitudinal retrospective study in
which investigators start by enrolling a group of people with disease (at CDC such persons are
called case-patients rather than cases, because case refers to occurrence of disease, not a
person). As a comparison group, the investigator then enrolls a group of people without disease
(controls). Investigators then compare previous exposures between the two groups.
14. • Crossover study; A special design of controlled trials in which half of the participants are
randomly assigned to start with the placebo and then switch to active treatment, while the
other half does the opposite.
• Cross-sectional study; An observationaldescriptive study design, not causal or relational,
in which, a sample of persons from a population is enrolled and their exposures and health
outcomes are measured simultaneously. The cross-sectional study tends to assess the presence
(prevalence) of the health outcome at that point of time without regard to duration.
• The cross-sectional study is weaker than either a cohort or a case-control study because a
cross-sectional study usually cannot disentangle risk factors for occurrence of disease
(incidence) from risk factors for survival with the disease. On the other hand, a cross-sectional
study is a perfectly fine tool for descriptive epidemiology purposes. Cross-sectional studies are
used routinely to document the prevalence.
• Retrospective study; An observational study design in which the investigators study present
and past events.
15. • Meta-analysis; A methodology to critically review research studies and statistically
combine their data to help answer questions that are beyond the power of single papers.
• Questionnaire; A means of collecting data from people where they provide written
responses to a set of questions, either in their own words (open-ended questions), or by
selecting from among pre-defined answers (closed response questions).
• Pilot study; A preliminary study to test the feasibility of the protocol, before implementing the
study proper. It may also be called “pre-test”.
• Phase I clinical trials; First trials of a new active ingredient or new formulation in humans,
often carried out in healthy volunteers.
• Phase II clinical trials; Trials performed in a limited number of subjects and often of a
comparative (e.g. placebo-controlled) design, to demonstrate therapeutic activity and to
assess the short-term safety of the active ingredient in patients suffering from a disease or
condition for which the active ingredient is intended.
• Phase III clinical trials; Trials including larger (and possibly varied) patient groups, with the
purpose of determining the short-and long-term
16. safety/efficacy balance of formulation(s) of the active ingredient, and of assessing its overall
and relative therapeutic value.
• Phase IV clinical trials; Studies performed after marketing of the pharmaceutical product
to discover rare and remote side-effects.
• Randomized controlled trials; Intervention studies characterized by the prospective
assignment of subjects, through a random method, into an experimental group and a control
group.
Odds ratio; Term used in case-control studies as a measure of the odds of having the risk
factor among people with the disease divided by the odds of having the risk factor among
people without the disease.
• Hypothesis; The research hypothesis is a tentative statement that can be tested by a scientific
research design.
• The key feature of analytic epidemiology is a comparison group.
• Assignment; The process in an experiment where the researcher allocates subjects to two or
more groups, trying to achieve having groups as identical as possible to allow a valid comparison
of the results. Matching and
17. random assignment are the two most common methods.
• Attributable risk; An estimate to quantify the contribution which a particular risk factor
makes in producing the disease within a population.
• Audit of a trial; A systematic examination, carried out independently of those directly
involved in the clinical trial.
• Blinding; A randomized controlled trial may be blinded if participants in the trial are likely to
change their behavior in a systematic way that may influence the outcome of the study when
they are aware of which intervention they receive. The term “masking” is often used instead of
“blinding”.
• Coding; A method of analysis of qualitative data obtained for example in interviews, where
categories are labelled to facilitate computer analysis and examination of relationships.
• Cost–benefit analysis; A type of economic study design in which both costs and benefits of
interventions are expressed in monetary units, allowing direct comparison of competing
interventions.
18. • Cost–effectiveness analysis; A type of economic study design in which the net monetary costs
of a health care intervention per unit measure of clinical outcome or effectiveness allows direct
comparison of competing interventions.
• Validity; The extent to which a test measures what it is intended to measure.
• External validity; The extent to which the results of the study sample may be generalized to
the population from which the sample was withdrawn; also called generalizability.
• Internal validity; The degree to which the investigator’s conclusions correctly describe what
actually happened in the study. It means that within the confines of the study, results appear to be
accurate, the methods and analysis used stand up to scrutiny, and the interpretation of the
investigators appears supported.
• Matching; A sampling method to ensure that the two groups to be compared have similar
characteristics. In an intervention study, pairs of similar “matched” subjects are formed and then
one member of the pair is randomly assigned to one group and the other member to the other
group.
19. • P value; The probability that a difference or an association as large as the one observed could have occurred by
chance alone.
• Type I error; The error committed when, on the basis of a statistical test applied to the sample
of data, a conclusion is made that there is evidence of an association between variables or
difference between groups in the population, when in fact there is no difference or association.
The probability of type I error is represented by the symbol alpha (α). Another name for alpha is
the level of statistical significance.
• Type II error; A “miss”, when, on the basis of a statistical test applied to the sample of data,
a conclusion is made that there is no evidence of an association between variables or difference
between groups in the population, when in fact there is a difference or association. The probability of type I error is
represented by the symbol beta (β).
• Population; An entire set of persons, animals, objects or events which the researcher intends to
study.
• Sample; A subset selected for the study from the larger population.
• Proposal; A document written for the purpose of obtaining funding for a research project.
• Protocol; The detailed written plan of the study. Any research study should have a protocol.
20. • Qualitative methods; A research approach that emphasizes the non-numerical data and
interpretive analysis.
• Quantitative methods; A research approach that emphasizes the collection of numerical data
or data than can be quantified, and statistical analysis.
• Risk factor; A factor that is believed to increase the probability of a certain outcome or illness.
• Demographic factor; such as age, race, or sex.
• Constitutional factor; such as blood group or immune status.
• Behavior; or act such as smoking or having eaten salsa.
• Circumstance; such as living near a toxic waste site.
• Sampling error; The discrepancy between the values obtained from the relatively small
sample and the larger population from which the sample was drawn.
• Selection bias; A systematic difference between people who are selected for a study and those
who are not selected.
• Sensitivity; of a diagnostic test is the proportion of people who test as positive to a
21. disease who really have the disease, i.e. they are true positive.
• Specificity; The proportion of people who test negatively for a disease.
• True negative; A diagnostic test correctly indicating that a person does not have the
disease.
• True positive; A diagnostic test correctly indicating that a person has the disease.
• Standard deviation; A measure of the dispersion or variability of a group of scores.
• Standard error; A statistical measure of the probability that the finding in the sample will
reflect the finding in the population from which the sample was drawn.
• Statistical significance; A statistic indicating that the result obtained is probably not due to
chance but is real. A statistically significant result does not necessarily mean that it is important
or interesting.
23. • Some research questions are best approached by statistical analysis of data. This is
quantitative research. Others are better answered by looking for patterns, features or themes
in the data. This is qualitative research.
• Whereas quantitative research aims to develop objective theories by generating quantifiable
numerical data, qualitative research aims to understand meaning. This might be the
meanings that people attribute to their work, their behaviors or beliefs, or their attitudes or
perceptions.
• Qualitative research is often based on methods of observation and enquiry; qualitative
research “explores the meaning of human experiences and creates the possibilities of change
through raised awareness and purposeful action”.
• Qualitative research focuses on life experiences; they are more about the “why” and “how”
rather than the “how many”, or “how often”.
24. • Qualitative study designs might be chosen for any number of reasons. In health, you might
be interested in finding out how nurses feel or experience care in the ICU; or you might want
to find out how people engaged in heavy substance use found the experience of connecting
with a support agency.
• Qualitative study designs are beneficial for certain types of research questions such as
those looking to provide unique insights into specific contexts or social situations.
• However, they are not as strong when wanting to find direct cause and effects links or where
a statistically significant result is required.
25. 5 W and One H questions
• This section attempts to answer the 5 W and One H questions—Who, What, When,
Where, Why and How.
• It should include detailed information on the interventions to be made, procedures to be
used, measurements to be taken, observations to be made, laboratory investigations to be
done etc.
29. • In a case report is a detailed report of the diagnosis, treatment, response to treatment,
and follow-up after treatment of an individual patient.
• A case study/case report can be used in the following instances:
• Where there is atypical or abnormal behaviour or development
• An unexplained outcome to treatment
• An emerging disease or condition
34. • Case reports and case series usually contain demographic information about the patient(s),
for example, age, gender, ethnic origin.
• When information on more than three patients is included, the case series is considered to
be a systematic investigation designed to contribute to generalizable knowledge (i.e.,
research), and therefore submission is required to the IRB (Consent form).
35. • Advantages
• Can be published quickly
• Provides very detailed information
• Allows detailed investigation into situations which would be unethical or impractical
to perform using another study design
• Disadvantages
• May include researcher bias
• Difficult to replicate
• Can't always be generalized to the broader population
• The concept of “case series” is not well defined in the literature and does not reflect a
specific research design.
• A case series should have more than four patients while four patients or less should be reported
individually as case reports.
36. • Critical appraisal tools
• JBI Critical Appraisal Checklist for Case Series
• JBI Critical Appraisal Checklist for Case Reports
38. • Analytical studies are of 2 types: observational and experimental.
• Observational studies are studies that we conduct without any intervention or
experiment. In those studies, we purely observe the outcomes.
• On the other hand, in experimental studies, we conduct experiments and
interventions.
43. •The stages of a Cross-Sectional study
• Repeated Cross-Sectional Data Analysis
44. • This design is transverse where we take a specific sample at a specific time
without any follow-up
• It allows us to calculate the frequency of disease (prevalence) or the frequency of
a risk factor
• This design is easy to conduct
• For example 1; if we want to know the prevalence of migraine in a population,
we can conduct a cross-sectional study whereby we take a sample from the
population and calculate the number of patients with migraine headaches.
Example 2; researchers studying developmental psychology might select
groups of people who are different ages but investigate them at one point in
time. By doing this, any differences between the ages groups can presumably be
attributed to age differences rather than something that happened over time.
45. • Which clinical questions does a Cross-Sectional study best answer?
• Cross-sectional study designs are useful when:
• Answering questions about the incidence or prevalence of a condition, belief
or situation.
• Establishing what the norm is for a specific demographic at a specific time.
For example: what is the most common or normal age for students
completing secondary education in Victoria?
• Justifying further research on a topic. Cross-sectional studies can infer a
relationship or correlation but are not always sufficient to determine a direct
cause. As a result, these studies often pave the way for other investigations.
46. Table -clinical questions does a Cross-Sectional study
Question Type Study Example
Frequency
How common is the outcome (disease, risk factor,
etc.)?
This cross-sectional study looks at how many
Australian people meet DSM-IV and ICD-10
diagnostic criteria for the major mental health
disorders.
Aetiology
What risk factors are associated with these
outcomes?
This cross-sectional study identifies the
characteristics of women calling the perinatal
anxiety & depression Australia (PANDA) national
helpline.
Diagnosis
Does the new test perform as well as the ‘gold
standard’?
This cross-sectional study investigates the accuracy
of a Client Satisfaction Questionnaire in relation to
client satisfaction in mental health service support.
47. • What are the advantages and disadvantages to consider when using a Cross-Sectional study design?
Advantages
• An efficient and fast study design option.
• Cross-sectional studies may still use some experimental approaches such as physically
observing participants.
• Using a cross-sectional design, multiple variables can be investigated at the one time. For
example, cross-sectional studies can collect data on a range of attributes in the one instance; the
gender, age, health conditions, access to services, etc.
• Cross-sectional studies are often useful when looking for an ethical approach to investigate
harmful situations that would otherwise be unethical if inflicted on a participant.
• Cross-sectional studies can identify potential correlations, associations and relationships
between variables.
Disadvantages
• It cannot define direct causation.
• Rare diseases and conditions can be hard to investigated
https://deakin.libguides.com/quantitative-study-designs/cross-sectional
48. Key characteristics of a cross-sectional study
The study takes place at a single point in time
It does not involve manipulating variables
It allows researchers to look at numerous characteristics at once (age,
income, gender, etc.)
It's often used to look at the prevailing characteristics in a given
population
It can provide information about what is happening in a current
population
49. • What does a strong Cross-Sectional study look like?
• Appropriate recruitment of participants. The sample of
participants must be an accurate representation of the
population being measured.
• Sample size. As is the case for most study types a larger
sample size gives greater power and is more ideal for a
strong study design.
• A suitable number of variables. Cross-sectional studies
ideally measure at least three variables.
50. • What are the pitfalls to look for?
• Cross-sectional studies are at risk of participation
bias, or low response rates from participants. If a
large number of surveys are sent out and only a quarter
are completed and returned then this becomes an issue as
those who responded may not be a true representation of
the overall population.
51. • Critical appraisal tools
Axis Appraisal Tool for Cross Sectional Studies
Critical Appraisal Tool for Cross- Sectional Studies (CAT-CSS)
Critical Appraisal of a Cross-Sectional Study on Environmental Health
Critical appraisal tool for cross-sectional studies using biomarker data
(BIOCROSS)
CEBM Critical Appraisal of a Cross-Sectional Study (Survey)
JBI Critical Appraisal checklist for analytical cross-sectional studies
Specialist Unit for Review Evidence (SURE) 2018. Questions to assist with the
critical appraisal of cross sectional studies
STROBE Checklist for cross-sectional studies
53. History
• These findings (and more) have come out of a large cohort
study started in 1972 by researchers at the University of Otago
in New Zealand. This study is known as The Dunedin Study
and it has followed the lives of 1037 babies born between 1
April 1972 and 31 March 1973 since their birth. The study is
now in its fifth decade and has produced over 1200 publications
and reports, many of which have helped inform policy makers
in New Zealand and overseas.
54. • Characteristics
• Cohort Studies are a type of observational longitudinal study.
• We conduct this study by comparing two samples from the
population: one sample with a risk factor while the other lacks this
risk factor
• It shows us the risk of developing the disease in individuals with the
risk factor compared to those without the risk factor (RR = relative
risk)
• We may approach this study by 2 longitudinal designs:
• Prospective: we follow the individuals in the future to know who
will develop the disease
• Retrospective: we look to the past to know who developed the
55. disease (e.g. using medical records)
• This design is the strongest among the observational studies
• For example – to find out the relative risk of developing chronic
obstructive pulmonary disease (COPD) among smokers, we take a
sample including smokers and non-smokers. Then, we calculate the
number of individuals with COPD among both.
56. • How Cohort Studies are carried out, A. Prospective;
https://deakin.libguides.com/quantitative-study-designs/cohortstudies
57. • How Cohort Studies are carried out-B. Retrospective;
https://deakin.libguides.com/quantitative-study-designs/cohortstudies
59. • What is a Cohort Study design?
• Cohort studies are longitudinal, observational studies, which
investigate predictive risk factors and health outcomes.
• They differ from clinical trials, in that no intervention, treatment,
or exposure is administered to the participants. The factors of interest
to researchers already exist in the study group under investigation.
• Study participants are observed over a period of time. The
incidence of disease in the exposed group is compared with the
incidence of disease in the unexposed group.
• Because of the observational nature of cohort studies they can only
find correlation between a risk factor and disease rather than the
cause.
60. • Cohort studies are useful if:
• There is a persuasive hypothesis linking an exposure to an
outcome.
• The time between exposure and outcome is not too long
(adding to the study costs and increasing the risk of participant
attrition).
• The outcome is not too rare.
61. • The stages of a Cohort Study
• A cohort study starts with the selection of a group of participants
(known as a ‘cohort’) sourced from the same population, who must
be free of the outcome under investigation but have the potential
to develop that outcome.
• The participants must be identical, having common characteristics
except for their exposure status.
• The participants are divided into two groups – the first group is
the ‘exposure’ group, the second group is free of the exposure.
62. • Types of Cohort Studies
Prospective
• The two groups of cohorts (exposed and un-exposed) are followed prospectively over time to
track the development of new disease.
• Example: In a prospective cohort study researchers compared four different groups of women
(two at-high risk groups, two low-risk groups) to investigate which groups were more likely to
develop PTSD symptoms after a birthing event.
Retrospective
• Cohorts are defined from a previous point in time, and are not followed up in the future.
• Information or data is collected from past clinical records and the outcome of interest is
investigated.
• Useful for tracking the progress of a disease with a long latency period.
• Example: used previously data collected to investigate whether there was an association between
birth experience and subsequent maternal care-giving attitudes and behaviour over a 12-month
period
https://deakin.libguides.com/quantitative-study-designs/cohortstudies
63. • Which clinical questions does this study design best answer?
Question Type Study Example
Risks What risk factors predict disease?
This cohort study looks at dietary and lifestyle risk factors and
investigates how they might contribute to hypertension in
women.
Aetiology What factors cause these outcomes?
This cohort study looks at factors in early life that may predict
the occurrence of adolescent suicide.
Prognosis
What happens with this disease over
time?
This cohort study examines the instances of recovery from a
first-time episode of psychosis.
Diagnosis
If the test is positive, what happens
to the patient?
This cohort study examines recently released adults from prison
who have been diagnosed with both a mental illness and
substance use disorder and investigates what happens to them
following their diagnosis.
https://deakin.libguides.com/quantitative-study-designs/cohortstudies
64. • What are the advantages and disadvantages to consider when using a
Cohort Study?
Advantages
• The only observational study design that directly investigates risk of
disease and the factors contributing to it.
• Ethically safe.
• Multiple outcomes can be measured.
• They are good for rare types of exposures, e.g. an exposure to a chemical
spill in a factory.
Disadvantages
• Not appropriate for rare diseases or those that take a long time to develop
e.g. mesothelioma.
• Not appropriate for studying multiple exposures.
• Can be costly and time consuming.
https://deakin.libguides.com/quantitative-study-designs/cohortstudies
65. • What does a strong Cohort Study look like?
• The aim of the study is clearly stated.
• It is clear how the sample population was sourced, including inclusion and
exclusion criteria. The sample group accurately reflects the population.
• Loss of participants to follow up.
• The control group is clearly described to minimize bias and confounding.
• It is clearly stated whether the study was blinded or not.
• The methodology was rigorously adhered to.
valid measurements and appropriate statistical tests.
• The conclusions are logically drawn from the results.
• Includes a clear description of the data, including accessibility and
availability.
66. • What are the pitfalls to look for?
• Confounding factors within the sample groups may be difficult to
identify.
• Participants may move between exposure/non-exposure
categories.
• Study may influence behavior of participants.
• Too many participants may drop out.
67. • Critical appraisal tools
• Critical appraisal checklist for cohort studies (JBI)
• CASP appraisal checklist for cohort studies
70. • We conduct this study by comparing 2 groups: one group with the disease (cases) and
another group without the disease (controls)
• This design is always retrospective
• We aim to find out the odds of having a risk factor or an exposure if an individual has a
specific disease (Odds ratio)
• Relatively easy to conduct
• For example – we want to study the odds of being a smoker among hypertensive patients
compared to normotensive ones.
• There are two groups of people: one has a health issue (Case group), and this group is
“matched” to a Control group without the health issue based on characteristics like age,
gender, occupation.
• We can look back in the patient’s histories to look for exposure to risk factors to the Case group,
but not the Control group.
• There is a link between carcinoma of the lung and smoking tobacco. These studies estimate the
odds between the exposure and the health outcome, however they cannot prove causality.
71. • Referred to as retrospective or case-referent studies.
• Stages of a Case-Control study
• This diagram represents taking both the case (disease) and the control (no disease) groups
and looking back at their histories to determine their exposure to possible contributing
factors.
• For Accessibility: A case control study is likely to show that most, but not all exposed
people end up with the health issue, and some unexposed people may also develop the health
issue).
72. • Which Clinical Questions does Case-Control best answer?
• The best used for Prognosis questions.
• For example: Do anticholinergic drugs increase the risk of dementia in later life?
73. • What are the advantages and disadvantages to consider when using Case-
Control?
Advantages • Find the source of an existing illness or epidemic.
• Cheap and quick.
• Few ethics issues as the patient already has the health condition
• Looks at multiple risk factors.
Disadvantages • Patient recall about their history can be inaccurate (recall bias).
• Certain risk factors may focus and ignore other exposures.
• No randomization is possible, lowering internal validity.
• Finding a Control group that matches the Case group appropriately can be difficult.
• Not prove a clear causal relationship between risk factors and illness, only calculates the odds.
Opportunities • Useful for rare conditions.
• Identify point of outbreak.
• Can look at many exposure factors of the patient’s environment.
Confounding* • If the health issue causes multiple common exposures…which is more likely. For example, having a chronic illness. spend more time
in hospital environments, have a lower immune system, and suffer high levels of stress – so any of these could potentially be the cause
of that chronic illness. The study must make an attempt to eliminate some of these exposures as causes if possible.
• If the Control group is overmatched.
• If the Control group is under-matched.
For example, if you could not find female Controls to match female Cases.
https://deakin.libguides.com/quantitative-study-designs/casecontrol
74. • What does a strong Case-Control study look like?
• A strong study will have:
• Well-matched controls.
• Detailed medical histories are available, reducing unreliable recall.
75. • What are the pitfalls to look for?
• Poorly matched or over-matched controls. Poorly-matched means that not
enough factors are similar between the Case and Control. e.g. age, gender,
geography. Over-matched conversely means that so many things match (age,
occupation, geography, health habits) that in all likelihood the
• Selection bias: Selection of Controls is biased. E.g. All Controls are in the
hospital, so they’re likely already sick.
76. • Critical appraisal tools
• CASP - Case Control Checklist
• JBI – Critical appraisal checklist for case control studies
• CEBMA – Centre for Evidence Based Management – Critical
appraisal questions (focus on leadership and management)
• STROBE - Observational Studies checklists includes Case control
• SIGN - Case-Control Studies Checklist
• NCCEH - Critical Appraisal of a Case Control Study for
environmental health
78. • Also known as interventional studies
• Can involve animals and humans
• Pre-clinical trials involve animals
• Clinical trials are experimental studies involving humans
• In clinical trials, we study the effect of an intervention compared to another
intervention or placebo.
• An example, I have listed the four phases of a drug trial:
• I: We aim to assess the safety of the drug (is it safe ?)
• II: We aim to assess the efficacy of the drug (does it work ?)
• III: We want to know if this drug is better than the old treatment (is it
better ?)
• IV: We follow-up to detect long-term side effects (can it stay in the market ?)
79. • In 1747, James Lind, a ship’s surgeon, tested his theory for preventing the
effects of scurvy by giving 12 sailors different dietary acids. He subsequently
found that only sailors who consumed citric acid in the form of oranges and
lemons improved. This trial looked at a sample cohort (12 sailors) from a broader
population (all the sailors) and tested whether exposing part of that cohort to an
intervention of interest (citric acid), and the other part of that cohort to a different
intervention (other dietary acids), resulted in different outcomes (improved
symptoms) for the two parts of the sample cohort.
81. Forms of interventions
• In randomized controlled trials, one group of participants receives the control,
while the other receives the tested drug/intervention. Those studies are the best
way to evaluate the efficacy of a treatment.
• Interventions should be described in detail, including a description of the
drug/device/vaccine that is being tested. Interventions could also be in the realm
of social sciences for example providing training or information to groups of
individuals.
• Procedures could be biomedical (collection of blood or sputum samples to
develop a diagnostic test), or in the realm of social sciences (doing a
questionnaire survey, carrying out a focus group discussion as part of formative
research, observation of the participant's environment, etc.).
82. • Standardized and/or documented procedures/techniques should be
described and bibliographic references, if not provided earlier should be
provided.
• Instruments which are to be used to collect information (questionnaires, Focus
group discussion (FGD) guides, observation recording form, case report forms
etc.) must also be provided.
• In the case of a randomized controlled trial additional information on the
process of randomization and blinding, description of stopping rules for
individuals, for part of the study or entire study, the procedures and conditions
for breaking the codes etc. should also be described.
• A graphic outline of the study design and procedures using a flow diagram
must be provided. This should include the timing of assessments.
83. • What is a Randomized Controlled Trial?
Lind’s experiment illustrates some principles of a randomized controlled trial, but
not all. The common important features of a randomized controlled trial include:
• Researchers pre-determine eligibility criteria for the population considered
for inclusion in the trial, resulting in a population that is reasonably similar in
important ways. From here a sample is taken; this sample are the trial
participants.
• Participants are randomly assigned to an experimental or control group.
This reduces the potential for bias and the impact of variables outside researcher
control.
• Researchers manage trial participants’ engagement with the study, including
exposure to the intervention of interest. This is a key difference to other,
observational
84. studies where researchers do not directly expose participants to
interventions.
• The experimental group is exposed to the intervention of interest
while the control group is not. Both groups are then followed in
order for a comparison to be made between their respective outcomes.
85. • The stages of a Randomised Controlled Trial
Principles Identified • Eligible population defined and sample cohorts enrolled as participants
Randomisation • Participants randomly allocated to experimental or control group
Pre-exposure
Measurement
• Feature (s) of interest measured in both groups
Exposure
• Experimental group exposed to intervention of interest
• Control group exposed to comparison intervention
Post-exposure
Measurement
• Feature (s) of interest measured in both groups
Analysis
• Feature (s) of interest in both groups are compared
• Conclusions about intervention of interest are made
https://deakin.libguides.com/quantitative-study-designs/rct
86. • Which clinical questions does this study design best answer?
• Randomized controlled trials are excellent at answering questions about the effects of an intervention on a population.
Question Type Study Example
Effectiveness
Is a proposed intervention as effective as the
established intervention?
This study looked at the effectiveness of
play-based interventions for pre-schoolers
with behavioural issues.
Side effects
Does a proposed intervention have worse side effects
than the established intervention?
This study looked at medication intended to
reduce blood loss after vaginal delivery.
Cost of treatment
Which intervention for a specific condition results in
less cost to a healthcare service?
This study compared two methods of
repairing aortic aneurysms.
Patient adherence to treatment
Which intervention are patients more likely to
positively respond to?
This study looked at whether SMS
messages improved adherence rates in
patients receiving antiretroviral therapy.
Duration of effect of treatment Which intervention provides longer-lasting benefit?
This study looked at treatments for
colorectal cancer and measured survival
rates among participants.
https://deakin.libguides.com/quantitative-study-designs/rct
87. • What are the advantages and disadvantages to consider when using a
Randomized Controlled Trial?
Advantages
• Randomisation and blinding reduce bias and impact of confounders.
Confounders are variables which impact the outcome of a study and are outside
the control of the researchers.
• Researchers have greater control over the study’s circumstances.
• Can lead to strong conclusions about a causal relationship between exposure
and feature(s) of interest.
Disadvantages
• Design, execution and evaluation can be complex, costly and lengthy.
• Recruitment of participants can be difficult for some research.
• May not be appropriate for some research due to ethical concerns.
• May not be appropriate for some research due to difficulty of blinding
participants for some interventions.
https://deakin.libguides.com/quantitative-study-designs/rct
88. • What does a strong Randomised Controlled Trial look like?
• Interest
• It is important for RCTs to begin with a clear understanding of what is being measured and
how measures will be taken, and for these to be adhered to throughout the life of the trial..
• Random allocation to groups
• In a RCT trial participants are randomly allocated to control or experimental groups. Well-
designed trials feature randomization that is as free from bias as possible. A strong report of a
RCT should also include details of the randomization method in order to be as transparent as
possible.
• Blinding of participants and administrators
• Blinding is do not know whether a participant has been allocated to the experimental or the
control group. This is done to avoid the influence of bias. “Single-blind” trials have only the
participants unaware of group allocation while “double-blind” trials have both the
participants and administrators unaware of group allocation.
• Appropriate sample characteristics and size
• Minimal bias
• It is difficult for a study to be entirely free of bias.
89. • What are the pitfalls to look for?
• Poor recruitment
• Poor randomization
• While randomization is an important strength of randomized controlled trials, some forms of
randomization are susceptible to bias.
• Participants lost to follow-up
• Intention-to-treat not adhered to in analysis
• Bias due to industry sponsorship of trial
• Many trials are conducted with the sponsorship of companies that sell the intervention being
studied in the trial. Common examples include pharmaceuticals or medical devices. Research
published in 2018 found that studies which had industry sponsorship were more likely to
report results favorable to the intervention of interest than studies not sponsored by industry.
This suggests the existence of a bias for the studies which received industry sponsorship.
90. • How should Randomized Controlled Trials be evaluated?
• Critical appraisal
• CASP (Critical Appraisal Skills Programme)
• CEBM (Centre for Evidence-Based Medicine)
• SIGN (Scottish Intercollegiate Guidelines Network)
• RoB 2 (Cochrane risk of bias tool for randomised trials)
Finally, while not technically a critical appraisal checklist, the CONSORT
guidelines for reporting randomised trials could be useful to help understand the
expectations for appropriate reporting of such a study.
91. General information
• Name and title of the investigator(s) who is (are) responsible for conducting the
research, and the address and telephone number(s) of the research site(s), including
responsibilities of each.
• Name(s) and address(es) of the clinical laboratory(ies) and other medical
and/or technical department(s) and/or institutions involved in the research.
• Name and address of the sponsor/funder.
94. • Three widely used scholarly styles: the parenthetical author–date system recommended by
1. The sequential numerical or Vancouver system;
• It is based on an American National Standards Institute (ANSI) standard
adapted by the National Library of Medicine (NLM) for databases such as
medline.
• In Vancouver style, up to six authors, the names of all the authors are written. If
there are more than six authors, then after writing the first six authors, ‘et al’ is
used.
• Each reference number is placed in parentheses or superscripted throughout
the text, tables, and legends.
• This style recommends the use of official abbreviations for titles of journals.
95. • While using Vancouver style, if an author’s name is to be used in text, it is mandatory to use
the citation number as well. For example, as Kaur (2) emphasized the high prevalence of
depression in elderly. If there is more than one author it is recommended to use term “et al”
after writing the sir name of first author.
• Format of Article; “Surname Initial(s). Title of article. Journal title/or title abbreviation.
Year; volume (issue): page(s). DOI - if available” * It is optional to omit the month and issue
number if a journal carries continous pagination. *It is also optional to use the database unique
idenfiers such as PMID for pubmed and the clinical trial registration number.
• Example; 1. Wilson S, Bond F. Political and personal readings of the earliest zone poem.
Urban Poetry. 2016;12:72–94. doi:00.0000/00000000000000.
2. Petrie KJ, Mueller JT, Schirmbeck F, Donkin L, Broadbent E, Ellis CJ et al.
96. Effect of providing information about normal test results on patients’ reassurance:
randomised controlled trial. British Medical Journal. 2007;334(7589): 352-354. Available
from: doi:10.1136/bmj.39093.464190.55.
• Format of Book; “Surname author Initial(s). In: Surname editor Initial(s), editor(s).
Book title. Place of publication: Publisher; Year. page(s).”
• Example; Kaur S, Singh M. In: Singh A, Kaur S, Kishore J. Comprehensive Textbook
of Elderly Care. New Delhi: Century Publications, 1st Edition 2014. p 239–248.
Citation; (1).
• Several studies have taken this approach to the text (1,2,5–8).
97. 2. APA STYLE;
• The APA style is a structured format for all sort of academic writings including the journal
articles, books and other commentaries devised by the American Psychological Association
(APA).
• This style is very widely used in social and behavioral sciences like psychology, sociology,
social work, nursing and education.
• While citing reference in text, where one needs to cite one work by one author, the following
format is used: “Author’s Surname (year)”.
• For example; Sharma (2014) reported that 43% of antenatal females experience intimate partner
violence.
• When the citation has three, four, or five authors, cite all authors when the reference appears
for first time; in subsequent citations, include only the surname of the first author followed by et
al. and the year.
98. • For example; Kaur, Sharma, Bakshi and Sinha (2012) reported high prevalence of
stress among nurses. (Used as first citation in text) Kaur et al. (2012) also found
• The order of the reference list is prepared by arranging all entries in alphabetical
order by the surname of first author followed by initials of the author’s given name.
The rule is to alphabetize letter by letter.
• When there are several works by the same author, they are to be arranged by year
of publication, the earliest first.
• For example, Sharma N (2010) precedes Sharma N (2014).
• One-author entries precede multiple-author entries beginning with the same
surname even if the multiple-author work was published earlier.
• For example, Kaur (2014) shall precede Kaur, Singh and Sharma (2010). This
style mandates writing names of all the authors in reference list up to seven authors.
• If there are more than seven authors, following format is used: Kaur, S.,
Sharma,
99. N., Sharma, S., Thakur, M., Agnihotri, N. Thakur M,.… Saini, S. (2015).
• Format of Article; “Author, A.A. Author, B. B., and Author, C. C. (year). Title
of article. Title of journal, xx, pp-pp. doi:xx.xxxxxxxxxx”
• Example; Ager, A. (2013). Annual Research Review: Resilience and child
well-being – public policy implications. Journal of Child Psychology and
Psychiatry, 54(4), 488–500. doi:10.1111/ jcpp.12030
• Format of Book; “Author, A.A. (Year of Publication). Title of work. Publisher
City, State: Publisher
”
.
• Examples; 1. Wilson, S., & Bond, F. (2016). Political and personal readings
of the earliest zone poem. Urban Poetry, 12, 72–94.
doi:00.0000/00000000000000
2. Kaur, S., Singh, M. (2014). Clinical Neuroscience and Critical Care
Nursing. 1st Edition. New Delhi : Jaypee Medical Publishers
Citation; (Kaur, Singh, 2016).
100. 3. Harvard style
• This is also known as Author and Date system.
• Harvard system puts the authors and the date of work being referred to at the appropriate point
in the text rather than using a number. This is called a “citation”.
• All the works cited are then listed at the end of the report/paper in an alphabetical order
according to the authors’ surname. The reader can then refer from the text to the reference.
• It is economical in terms of time. It is very flexible as entries can be added, deleted, or changed
with a minimum of disruption to the rest of the document.
• In addition, the reader can tell immediately who the author is and when the study was
published. It emphasizes the name of the author and the publication year in the text with full
bibliographic details in a reference list.
• Format of Article; “Author(s) of article’s FAMILY/SURNAME, Initials. (Publication
101. year) Title of article. Title of journal - italicised or underlined. Volume number (Part number/
month). pp. followed by the page number of the article
”
.
• Example; Kaur, S, Singh, A., Dhillon, M.S., Tewari, M.K., Sekhon, P.K. (2015). Incidence of
bedsore among the admitted patients in a tertiary care hospital. JPMER, vol 49, no. 1, pp. 26-31.
Citation; Kaur, Singh, Dhillon, Tewari, Sekhon (2015) has reported that-
• Format of Book; “FAMILY/SURNAME, Initials. (Publication year) Book title – italicized.
Series title and volume if applicable. Edition – if not the first. Place of publication: publisher
”
.
”
.
• Examples; Dempsey, P.A. and Dempsey, A.D. (2000) Using Nursing Research: Process,
Critical Evaluation, and Utilization. 5th ed. Philadelphia: Lippincott Williams and
Wilkins.
• Citation; Dempsey, Dempsey (2014) emphasized that_.
• The reference list for sequential numerical citations is arranged, not surprisingly, by the
numerical sequence of the citations.
102. References
1. Tullu MS. Writing the title and abstract for a research paper: Being concise, precise, and meticulous is the key. Saudi J Anaesth. 2019;13(Suppl
1):S12-S17. doi:10.4103/sja.SJA_685_18
2. WHO. Recommended format for a 'research protocol". https://www.who.int/groups/research-ethics-review-committee/recommended-format-
for-a-research-protocol 14 October 2020
3. Abbas H. An introduction to different types of study design. https://s4be.cochrane.org/blog/2021/04/06/an-introduction-to-different-types-of-
study-design/ April 6, 2021.
4. Deakin University. Quantitative Study Designs. https://deakin.libguides.com/quantitative-study-designs/casestudy Last Updated: Jun 4, 2021.
5. Grimes, DA, & Schulz KF. An overview of clinical research: The lay of the land. The Lancet, 2002;359(9300), 57-61
.
6. Sayre JW, Toklu HZ, Ye F, Mazza J, Yale S. Case Reports, Case Series - From Clinical Practice to Evidence-Based Medicine in Graduate
Medical Education. Cureus. 2017 Aug 7;9(8):e1546. doi: 10.7759/cureus.1546. PMID: 29018643; PMCID: PMC5630458
.
7. Abu-Zidan FM, Abbas AK, Hefny AF. Clinical "case series": a concept analysis. Afr Health Sci. 2012 Dec;12(4):557-62. PMID: 23515566;
PMCID: PMC3598300
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8. Lander B, Balka E. Exploring How Evidence is Used in Care Through an Organizational Ethnography of Two Teaching Hospitals. Med
Internet Res 2019;21(3):e10769) DOI:10.2196/10769
9. Kannel WB. The Framingham Study: its 50-year legacy and future promise. J Atheroscler Thromb 2000;6:60-6.
10. CDC. Principles of Epidemiology in Public Health Practice, Third Edition An Introduction to Applied Epidemiology and Biostatistics.
https://www.cdc.gov/csels/dsepd/ss1978/lesson1/section7.html Last reviewed: May 18, 2012 (archived document)
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