Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Public Health > Overview of research methodology > Flashcards

Overview of research methodology Flashcards

1
Q

What is research?

A

Old French term “Re-cerchier” meaning to “search intensively”: a process by which we aim to discover new knowledge. Uses a systematic process  Scientific Method

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why is critical appraisal required

A
  • Published research is not always reliable or relevant.
  • We need a systematic framework to conduct research, interpret research and assess quality.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why is study design important?

A
  1. Specific questions need specific design (feasibility, ethics)
  2. Different designs have different causal strengths
  3. Determines nature of bias and confounding (validity)
  4. Affects resources needed: sample size, staff, expertise, access to records, time!  efficiency
  5. Ethical issues vary
  6. May influence measurement accuracy (e.g. prospective vs retrospective data collection)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Descriptive study

A

No comparison group. Answers who, what, when, where.
E.g. case study, case series, non-analytic cohort

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

advantages of descriptive study

A

Hypothesis generation
Health service planning & management

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

disadvantages of descriptive study

A

Cannot establish causality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Cross sectional study

A

Exposure and outcome measured at one point in time
= snap-shot
= prevalence study

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Advantages of cross sectional study

A

-Relatively cheap & easy
-Measure multiple variables at the same time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Disadvantages of cross sectional study

A
  • Cannot measure temporality
    -Cannot measure incidence
    -Information bias (recall bias); Selection bias
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Cohort study

A

“A group of people who share a common characteristic or experience within a defined period”.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Advantages of cohort study

A

–Temporality
-Can calculate incidence
-Useful for rare exposures
-Can study multiple outcomes (of single exposure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Disadvantages of cohort study

A

-Loss-to-follow-up
-Detection bias
-Time consuming, expensive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

retrospective

A

Study begins when outcome has already occurred
Participants grouped on exposure (NOT outcome status)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

prospective

A

Outcome has not yet occurred
Participants grouped on basis of exposure
Follow up to see if outcome occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

case control study

A

Identify cases (those who have the outcome/disease)
Choose controls (those without outcome/disease)
Measure exposure in both cases and controls
Common sources  hospital, neighbourhood, family members. “Matched controls”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Advantages of case control study

A

Efficient
Relatively quick
Good for rare outcomes
Can study multiple exposures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Disadvantages of case control study

A

Selection bias (selection of controls)
Information bias: Recall
Can only calculate odds ratio
No temporality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Randomised Control study

A

Similar to cohort, but exposure
assigned randomly & always prospective

Randomisation is a way to deal with confounders (known & unknown)
Participants have equal chance of receiving exposure/intervention as the control.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Advantages of RCT

A

Minimal bias/confounding
Strong evidence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Disadvantages of RCT

A

Ethical issues
Time-consuming, expensive
Loss-to-follow-up
Not suitable for all research questions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is blinding or masking in research studies?

A

Blinding or masking involves concealing information about the intervention received (e.g., treatment or placebo) from participants, clinicians, field workers, lab personnel, or statisticians involved in the study. This is done to prevent bias in the assessment of outcomes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the types of blinding?

A

Blinding can be single-blinded, where either participants or researchers are unaware of the intervention received, or double-blinded, where both participants and researchers are unaware. Triple-blinding involves concealing information from participants, researchers, and outcome assessors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why is blinding used in research studies?

A

Blinding is used to minimize bias that could result from knowledge of the intervention. It helps ensure that participants behave consistently and that researchers assess outcomes objectively, reducing the risk of bias in study results.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Ecological studies

A

Work with population or group-level variables. Previous examples were all looking at individual level. Study design itself can vary: but mostly cross-sectional ecological study

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Advantages ecological studies

A

Hypothesis generation
Relatively quick and cheap

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Disadvantages of ecological studies

A

Ecological fallacy
Confounding, bias
Cannot determine causality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is occurrence?

A

Describes the burden of disease (how much there is).

28
Q

When do we use measures of occurrence or frequency

A

Quantify the extent of an outcome(e.g. occurrence of disease) populations in order to motivate for response/ resources.
E.g How many cases of diabetes were diagnosed in South Africa in 2022?

29
Q

Measures of occurrence/ frequency

A

Prevalence
Incidence (Incidence Proportion & Incidence Rate)
Odds

30
Q

What is association?

A

Compares the occurrence of disease in different exposure groups. Explores the relationship between exposure(s) and an outcome(s) of interest and whether it could be causal.

31
Q

When do we use measures of association

A

We want to understand how exposures and outcomes are related, if one causes the other, if we want to modify exposure to increase or decrease the outcome.
E.g. How strongly is smoking related to lung cancer?/
How many cases of lung cancer could we prevent by implementing tobacco control measures?

32
Q

measures of disease association

A

-Relative measures
Prevalence ratio
Incidence: Risk ratio or rate ratio (RR)
Odds ratio (OR)

-Absolute measures
Proportion / rate and risk differences
Number needed to treat etc.

33
Q

cases/ counts

A

Individuals in a population who have the disease, health disorder, or suffers the event of interest. Usually forms the numerator for measures of disease frequency (A)

34
Q

population at risk (N)

A

The population from which cases come from. Usually forms the denominator in calculations of disease frequency

35
Q

ratio

A

Comparison of two groups (numerator and denominator can be related)

36
Q

rate

A

A rate is a ratio with a time component / change over time

37
Q

proportion

A

A ratio in which the numerator is included in the denominator (A/N)

38
Q

odds

A

A ratio in which the numerator is not included in the denominator (A/N-A)

39
Q

prevalence

A

The number of cases of disease in a population at one point in time, as a proportion of the total number of persons in that population i.e. proportion of a population that has the disease/event at a specific point in time

no of disease/ total population at point in time

40
Q

incidence proportion (risk)

A

no of new cases in a given time period/ no at risk at beginning of time period

41
Q

incidence rate

A

no of new cases in a given time period/ total person- time of observation or risk during that period

Used if incomplete follow-up – i.e. loss to follow-up/open population (participants entering and leaving)

IR takes into account the:
Size of population (number of individuals in a population that become ill)
length of time contributed by all persons during the period they were in the population.

42
Q

aims of measures of association

A

Measures of association allow us to compare measures of disease frequency
Quantify the association

43
Q

relative measures of association

A

Measures of disease frequency are divided by one another
Ratios of two measures of disease frequency

44
Q

Absolute measures of association

A

Measures of disease frequency are subtracted from one another
Tells us about the Public Health Impact

45
Q

relative measures of association: ratio

A

-prevalence ration
- cumulative incidence ratio
- incidence rate ration
- odds ratio

46
Q

Prevalence ratio

A

Prevalence of disease in exposed / prevalence of disease in unexposed

47
Q

Cumulative incidence ratio

A

Risk (incidence proportion) of disease in exposed / risk (incidence proportion) of disease in unexposed

Also called risk ratio or relative risk

48
Q

incidence rate ratio

A

Rate (incidence rate) of disease in exposed / rate (incidence rate) of disease in unexposed

Also called rate ratio or relative rate

49
Q

odds ratio

A

Odds of exposure in disease / odds of exposure in non-diseased*

50
Q

Interpretation of Relative Measures of Association: <1 (less than 1):

A

The numerator is smaller than the denominator
The exposure is “protective”/disease is less likely in the exposed

51
Q

Interpretation of Relative Measures of Association =1

A

The numerator and denominator are equal
There is no difference in disease occurrence between the exposed and unexposed

52
Q

Interpretation of Relative Measures of Association >1 (greater than 1):

A

The numerator is larger than the denominator
The exposure is “harmful”/disease is more likely in the exposed

53
Q

Interpretation of Relative Measures of Association = Significant?

A

The relative measure of association is an estimate, and should be reported and interpreted with a 95% Confidence Interval (generated by statistical software)
If the 95% confidence interval includes the value of 1, then not significant

54
Q

risk ratio

A

ratio of two probabilities

probability of an event occurring in treatment group / probability of the event occurring in control group

risk in exposed/ risk in unexposed

based on incidence- cohort studies, RCT

55
Q

odds ratio

A

ratio of two odds

odds of exposure occurring in cases group/ odds of exposure occurring in control group

odds in cases/ odds in controls

case control

56
Q

prevalence ratio

A

prevalence exposed/ prevalence unexposed

for cross sectional studies

57
Q

Absolute measures of association

A
  • prevalence difference
  • incidence proportion difference
  • incidence rate difference
58
Q

prevalence difference

A

Prevalence of disease in exposed - prevalence of disease in unexposed
=The number of cases that could be eliminated if the exposure was eliminated

59
Q

incidence proportion difference

A

Risk (incidence proportion) of disease in exposed - risk (incidence proportion) of disease in unexposed

60
Q

incidence rate difference

A

Rate (incidence rate) of disease in exposed - rate (incidence rate) of disease in unexposed

61
Q

Population Risk or Rate difference: PRD = Rt – Ru

A

Population risk difference gives you the excess number of cases in the whole population that is associated with the exposure

Can use incidence rate / incidence proportion or prevalence
-Rt = Incidence rate OR incidence proportion OR prevalence in the whole population
-Ru = Incidence rate OR incidence proportion OR prevalence in the unexposed

62
Q

Attributable Proportion:

A

This calculates the proportion of disease that is attributable to the exposure, also known as attributable risk (or fraction)
Can calculate attributable proportion in the exposed or in the population

63
Q

Attributable Prop in Exposed

A

APe=[(Re – Ru) / Re]

APe is the attributable proportion in the exposed
Re is the incidence rate, cumulative incidence or prevalence in the exposed
Ru is the incidence rate, cumulative incidence or prevalence in the unexposed
APt is the attributable proportion in the total population
Rt is the incidence rate, cumulative incidence or prevalence in the total population

64
Q

Attributable Prop in Population

A

APt=(Rt – Ru) / Rt

APe is the attributable proportion in the exposed
Re is the incidence rate, cumulative incidence or prevalence in the exposed
Ru is the incidence rate, cumulative incidence or prevalence in the unexposed
APt is the attributable proportion in the total population
Rt is the incidence rate, cumulative incidence or prevalence in the total population

65
Q

Number needed to treat

A

1 / [risk in exposed) – (risk in unexposed)

The number needed to be treated or the exposure to be prevented in order to prevent one case of disease

66
Q

Interpretation of Absolute Measures of Association

A

If difference=0 there is no association between exposure and disease

Difference will lie between -100% and 100%, or -1 and 1 when expressed as proportions.

E.g. Prevalence difference = 0.08
“ In this study, smokers had 8 additional cases of TB per 100 people compared to non-smokers”

Public Health (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions