Study Design Flashcards

1
Q

What is design of a study based on?

A

Identification or grouping of subjects

Time course of investigation

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2
Q

Explain how identification of subjects is relevant to study design

A

E.g. exposed vs non-exposed

or difference in outcomes e.g. cases vs controls

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3
Q

Explain how time course of investigation is relevant to study outcome

A

E.g. prospective or retrospective

or cross-sectional where exposure and outcome are measured together

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4
Q

Name some descriptive studies

A

Case report/series

Cross sectional studies

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5
Q

Name some analytical studies

A

Case-control studies
Cohort studies
Ecological studies

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6
Q

Name some experimental studies

A

Controlled trials

Uncontrolled trials

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7
Q

What happens in prospective studies?

A

Subjects exposed to a risk factor or invention are assembled and researcher awaits outcome

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8
Q

What happens in retrospective studies?

A

Group of individuals assembled because they have already experienced the exposure

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9
Q

Aim of descriptive studies

A

Describe characteristics of a group of subjects

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10
Q

What does not happen in descriptive studies compared to other studies?

A

No testing of causal hypothesis

No comparison with other groups

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11
Q

What can cross-sectional studies do that case reports/series cannot?

A

Suggest presence of putative relationship among variables

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12
Q

Another name for cross-sectional studies?

A

Prevalence studies - describe various attributes of subjects at a single point in time

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13
Q

What type of studies are surveys?

A

Cross-sectional

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14
Q

What type of studies are census?

A

Cross-sectional

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15
Q

What happens in prospective longitudinal studies?

A

Observations are repeated in same population over long period of time

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16
Q

What are prospective longitudinal studies helpful for?

A

Studying natural course of illness, risk factors and incidence rates

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17
Q

Disadvantages of longitudinal studies

A

Costly

Time consuming

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18
Q

What are analytical studies?

A

Comparative analysis of two groups to measure association between variables of interest

19
Q

Populations that can be studied in cross-sectional studies

A

Exposed and diseased
Exposed but no disease
Not exposed but diseased
Not exposed and no disease

20
Q

What happens in a case-control study?

A

Researcher assembles group of subjects who have experienced the outcome - cases and who have not - controls
Researcher estimates proportion in each group who have experienced exposure.

21
Q

When is hypothesis of case control study supported?

A

If proportion of exposed subjects is larger among case group than control group

22
Q

What is a cohort study?

A

Observational study of a group of people with specific characteristics of exposure who are followed up to detect an outcome

23
Q

What type of study is an ecological study?

A

Analytical

24
Q

What happens in an ecological study?

A

Data is gathered to describe what happens in a group rather than an individual

25
Q

What is the unit of measurement in an ecological study?

A

Population

26
Q

What is the assumption underlying ecological studies

A

All members of a given population are equally exposed and carry same risk of disease

27
Q

Problem of ecological studies

A

Tells us nothing about the individual

Does not note individual differences and risk factors

28
Q

What is ecological fallacy?

A

Drawing individual conclusions based on group-level observations in ecological studies

29
Q

What happens in experimental studies?

A

Exposure is experimentally assigned to groups in variable fashion to observe effect

30
Q

How are experimental studies different to cohort studies?

A

Deliberate manipulation of exposure (i.e. intervention)

31
Q

What type of study is a clinical trial?

A

Experimental

32
Q

What is another name for experimental studies?

A

Interventional

33
Q

What questions does a cross-sectional study ask?

A

How common is a condition?

What is the nature of this sample?

34
Q

What questions does a case-control study ask?

A

What are the causes of this outcome?

35
Q

What questions do interventional studies ask?

A

What is the effect of this intervention?

36
Q

What questions do cohort studies ask?

A

What are the effects of this risk factor/exposure?

37
Q

Best study to enquire treatment effectiveness?

A

Pragmatic RCT

Systematic review

38
Q

Best study to enquire treatment efficacy

A

Experimental RCT

Systematic Review

39
Q

Best study to enquire causation/aetiology?

A

Cohort

Case-control

40
Q

Best study to enquire prognosis?

A

Cohort

41
Q

Best study to enquire diagnostic assessment (new tool)?

A

Cross-sectional comparison to gold standard

42
Q

Best study to enquire health economics?

A

Cost-effectiveness study

43
Q

Best study to enquire ‘meaning’ or health ‘experience’

A

Qualitative study