Research Study Designs

Question 1

framework, or the set of methods and procedures
used to collect and analyze data on variables

Answer 1

research study design

Question 2

type of study design used to answer a
particular research question is determined by the?

Answer 2

nature of the question

the goal of research

the availability of resources

Question 3

the design of a study can affect the _____ of
its results

Answer 3

validity

Question 4

case reports
case series
cross-sectional studies

Answer 4

descriptive

Question 5

observational and experimental

Answer 5

analytical

Question 6

cross-sectional studies
cohort studies
case-control studies

Answer 6

observational

Question 7

researcher is documenting a
naturally occurring relationship between the
exposure and the outcome

researcher does not do any active intervention
in any individual, and the exposure has already
been decided naturally or by some other factor

Answer 7

observational studies

Question 8

looking at the incidence of lung cancer in smokers versus nonsmokers, or
comparing the antenatal dietary habits of mothers
with normal and low-birth babies

Answer 8

observational

Question 9

experiments where the researcher actively
performs an intervention in some or all members of
a group of participants

Answer 9

interventional studies

Question 10

T or F: intervention could take many forms

Answer 10

T

Question 11

administration of a drug or vaccine, performance of a diagnostic or therapeutic
procedure, and introduction of an educational tool

Answer 11

interventional studies

Question 12

➔ Merely try to describe the data on one or more
characteristics of a group of individuals.
➔ Do not try to answer questions or establish
relationships between variables

Answer 12

descriptive studies / nonanalytical studies

Question 13

Type of Study Design: A survey of dietary habits among
pregnant women or a case series of patients with
an unusual reaction to a drug.

Answer 13

Descriptive

Question 14

refers to the description of a patient with an unusual disease or with simultaneous
occurrence of more than one condition

Answer 14

Case reports

Question 15

refers to the description of a patient with an unusual disease or with simultaneous
occurrence of more than one condition EXCEPT that it is an
aggregation of multiple (often only a few) similar
cases

Answer 15

case series

Question 16

are anecdotal and of limited value

Answer 16

case reports and case series

Question 17

➔ Involve the collection of information on the
presence or level of one or more variables of
interest (health-related characteristic), whether
exposure (e.g., a risk factor) or outcome (e.g., a
disease) as they exist in a defined population at
one particular time.

Answer 17

cross-sectional studies

Question 18

in ________, the
investigator also assesses the relationship between
the presence of an exposure and that of an
outcome

Answer 18

cross-sectional

Question 19

can be thought of as
providing a “snapshot” of the frequency and
characteristics of a disease in a population at a
particular point in time

are very good for measuring the prevalence
of a disease or of a risk factor in a population

are very helpful in assessing the disease burden and healthcare needs

are usually simple to do
and inexpensive

do not pose much of a challenge from an
ethics viewpoint

Answer 19

cross-sectional studies

Question 20

carry a risk of bias

Answer 20

cross-sectional

Question 21

The results of the cross-sectional study may not represent the true situation in the population.
This could arise from either ____ bias or
____ bias

Answer 21

selection, measurement

Question 22

looking for association between an
exposure and an outcome across populations
rather than in individuals.

Answer 22

ecological (correlational) study design

Question 23

convenient to do since the data have often
already been collected and are available from a
reliable source

useful when the differences in exposure between individuals within a group are much smaller than the differences in exposure between groups.

Answer 23

ecological

Question 24

➔ Attempt to test a hypothesis and establish causal relationships between variables.
➔ In these studies, the researcher assesses the effect of an exposure (or intervention) on an outcome.
➔ Can be observational (if the exposure is naturally
determined) or interventional (if the researcher
actively administers the intervention).

Answer 24

Analytical studies

Question 25

defined as a “group of people with a shared characteristic

Answer 25

cohort

Question 26

different groups of people with varying levels of exposure are followed over time to evaluate the occurrence of an outcome

Answer 26

cohort

Question 27

➔ These participants have to be free of the outcome at baseline ➔ The presence or absence of the risk factor (exposure) in each subject is recorded. ➔ The subjects are then followed up over time (longitudinally) to determine the occurrence of the outcome.

Answer 27

cohort

Question 28

are FORWARD-DIRECTION studies (moving from exposure to outcome) and are typically PROSPECTIVE studies (the outcome has not occurred at the start of the study)

Answer 28

cohort studies

Question 29

researcher first enrolls cases (participants with the outcome) and controls (participants without the outcome) and then tries to elicit a history of exposure in each group.

Answer 29

case-control

Question 30

these are BACKWARD-DIRECTION studies (looking from outcome to exposure) and are always RETROSPECTIVE (the outcome must have occurred when the study starts)

Answer 30

case-control studies

Question 31

cases are identified from hospital records, death certificates or disease registries

Answer 31

case-control

Question 32

T or F : The controls are not required to resemble cases in all respects, except for the absence of disease.

Answer 32

F

Question 33

What are the types of Interventional Studies?

Answer 33

1. Randomized controlled trials 2. Nonrandomized controlled clinical trials 3. Interventional studies without concurrent controls 4. Before-after (pre-post) studies 5. Factorial study design 6. Crossover study design 7. Cluster randomized trials

Question 34

group of participants fulfilling certain inclusion and exclusion criteria is “randomly” assigned to two separate groups, each receiving a different intervention

Answer 34

randomized controlled trials

Question 35

T or F: Random assignment implies that each participant has an equal chance of being allocated to the two groups.

Answer 35

T

Question 36

The use of randomization is a major distinguishing feature and strength of this study design.

Answer 36

RCT

Question 37

this term refers to the presence of a concurrent control or comparator group

Answer 37

controlled

Question 38

RCT have two or more groups : the ___ and ___

Answer 38

treatment and control

Question 39

receives no intervention or another intervention that resembles the test intervention in some ways but lacks its activity (e.g., placebo or sham procedure, referred to also as “placebo-controlled” or “sham-controlled” trials) or another active treatment (e.g., the current standard of care)

Answer 39

control group

Question 40

In this design, participants are assigned to different intervention arms without following a “random” procedure.

Answer 40

Nonrandomized Controlled Clinical Trials

Question 41

this may be based on the investigator's convenience or whether the participant can afford a particular drug or not

Answer 41

NRCT

Question 42

This study design is susceptible to bias – with patients in the two groups being potentially dissimilar – and hence validity of the results obtained is low

Answer 42

NRCT

Question 43

When a new intervention, e.g., a new drug, becomes available, it is possible to a researcher to assign a group of persons to receive it and compare the outcome in them to that in a similar group of persons followed up in the past without this treatment (”historical controls”)

Answer 43

Interventional Studies without Concurrent Control

Question 44

This is liable to a high risk of bias, e.g., through differences in the severity of disease or other factors in the two groups or through improvement over time in the available supportive care.

Answer 44

Interventional Studies without Concurrent Control

Question 45

In this design, a variable of interest is measured before and after an intervention in the same participants

Answer 45

Before-After (Pre-post) studies

Question 46

Type of Study Design : measurement of glycated hemoglobin of a group of persons before and after administration of a new drug (in a particular dose schedule and at a particular time in relation to it) or number of traffic accident deaths in a city before and after implementation of a policy of mandatory helmet use for two-wheeler drivers

Answer 46

Before-After studies

Question 47

If two (or more) interventions are available for a particular disease condition, the relevant question is not only whether each drug is efficacious but also whether a combination of the two is more efficacious than either of them alone.

Answer 47

Factorial Study Design

Question 48

This design allows the study of TWO INTERVENTIONS in the SAME trial WITHOUT unduly increasing the required number of participants, as also the study of interaction between the two treatments.

Answer 48

Factorial Study Design

Question 49

Type of Study Design : Two interventions – A and B. The participants are randomly allocated to one of four combinations of these interventions – A alone, B alone, both A and B, and neither A nor B (control).

Answer 49

Factorial Study Design

Question 50

The advantages of this design are: ★ Comparison of each intervention with the control group, ★ Comparison of the two interventions with each other, and ★ Investigation of possible interactions between the two treatments (whether the effect of the combination differs from the sum of effects of A and B when given separately)

Answer 50

Factorial Study Design