Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

HOSA Epidemiology > Types of Studies > Flashcards

Types of Studies Flashcards

1
Q

2 types of edpidemiologic studies

A

observational
experimental

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

Experimental Studies

A

an active attempt to change a disease determinant or the progress of a disease through treatment

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

what do major experimental study designs include?

A
  • randomized controlled trails,
  • field trials, (healthy participants)
  • community trials (ppl in the community)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

randomized controlled studies (clinical trials)

A
  • designed to stude the effects of a particular intervention, usually a treatment for a specific disease
  • partients are alloved into groups randomly
  • ## should be comparable at the start of the investigation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Field Trials

A
  • involve healthy people who are presumed at risk
  • aimed at reducing exposure
  • often ligistically complicated and expensive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

FIeld Trial groups

A

preventiatice intervention and no intervention (control group)

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

community trials

A

treatment groups are communities rather than individuals
- diseases that are influenced by social conditions
- prevention includes changing behaviours

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

Limitations of a community trials

A
  • small number of communitites can be involved
  • differences can be attributed to the study and not other factors
  • random isn’t always possible
  • difficult to isolate the general social change
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Sources of Error

A
  • Random
  • Systematic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Random Errors

A

when the value of a sample measurement diverges from the true population value due to chance alone.

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

3 major sources of random errors

A
  • individual biological variation
  • sampling error
  • measurement error
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

individual biological variation

A

always occurs no measurement is perfectly accurate

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

Sampling Error

A

caused by the fact that a small sample is not representative of all the population’s variables
- increasing size can help, not necessarily

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

Measurement error

A

can be reduced by strict protocols and making individual measurements as precise as possible

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

What do you need to perform sample size calculations?

A
  • statistical significance to be able to tell the difference
  • acceptable error
  • magnitude of the effect
  • amount of disease
  • relative sizes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how many controls should you have for each case

A

more than four controls for each case

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

Systematic Error (or bias)

A

occurs when results differ in a systematic mannor from true values

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

high accuracy

A

a study with small systematic error, not affected by sample size

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

2 principle biases

A

selection bias
- measurement or classification bias

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

Selection Bias

A

a systematic difference between the characteristics of the people selected for a study and the characteristics of those who are not

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

Healthy Worker Effect

A

when the disease or factor under investigation makes people unavailable for the study

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

Measurement Bias

A

occurs when the individual measurements or classification of disease or exposure are inaccurate

  • dif labs cna get dif results
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

recall bias

A

occurs when there is a differential recall of information by cases and controls

participants don’t remember past things accurately.

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

blind study

A

investigators do not know how the participants are classified

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
double blind study
investigators and participantsand researchers do not know the treatment or intervention
26
Confounding
can occur when another exposure exists in the study population and is associated both with the disease and the exposure being studied.
27
methods of controlling confounding
- randomization - restriction - matching analysis stage: - stratification - statistical modeling
28
Randomization to control confounding
the method for ensuring that potential confounding variables are equally distributed among the groups being compared.
29
Restriction to control confounding
limiting the study to people who have particular characteristics, limit such that confounding characterisitcs are not present in the sample
30
Matching to control confounding
selecting study participants to ensure that potential confounding variables are evenly distributed in the two groups being compared, matching a person with a confounding variable to another.
31
Stratification /Statistical Modelling to control confounding
used in large studies because it preferable than doing things during design
32
Stratification
involves the measurement of the strength of associations in well defined and homogenous categories, if age is a confounding variable measure in age groups
33
Statiscal modeling
range of statistical techniques
34
validity
an expression of the degree to which a test is capable of measuring what it is intended to measure valid = responds to the truth
35
2 types of validity
internal validity external validity
36
Interval validity
the degree to which the results of an observation are correct for the partical group being studied necessary but does not guarantee external validity
37
External Validity
the exntent to which the results of a study apply to people or laborities not involved - external quality control - judgements - supported if similar results are found in studies in other populations
38
Informed Consent
free and voluntary informed consent must be obtained, must retain the right to withdraw at any time
39
an observational study
investigate measures, but it does not intervene
40
2 types of observational studies
- descriptive study - analytical study
41
descriptive study
limited to a description of the occurrence of a disease in a population often the first step in an epidemiogic investigation
42
analytical study
goes further by analysing relationships between bealth staus and other variables
43
ecological studies
or correlational studies and useful for generating hypotheses, units of analysis are groups - comparing different populations through time or place
44
ecological fallacy
inaproriate conclusions fromt he study are drawn, the association observed at the group level does not reflect that at the individual level.
45
Cross sectional studies or prevalence studies
measure of the prevalence of disease measurements of exposure and effect are made at the same time effect line follows exposure line there is a correlation
46
Case-control studies
involves cases and suitable control group of people unaffect by the disease or outcome variable
47
cases
people with a disease or other oucome variable of interest
48
control group
the comparison of reference of the case group - healthy ppl
49
Cohort studies
aka follow-up or incidence studies begin with a group of people who are free of disease and who are classified into subgroups according to exposure to a potential cause of disease or outcome
50
Nested Case-Control Studies
cases and controls are both chosen from a difined cohort
51
risk =
attack rate
52
risk among people who are exposed =
people with disease / total number of people exposed
53
Risk among people not exposed
number of people with disease / total number of people not exposed
54
Relative risk =
risk among people exposed / risk among people not exposed
55
If relative risk >1
exposure and disease are positively associated (more exposed people have the disease)
56
Relative risk = 1
exposure and disease are not associated
57
relative risk <1 exposure
and disease are engatively associated (more unexposed people have the disease), those exposed are protected from the disease
58
attributable risk =
risk of people exposed - risk of people not exposed the proprtion of people who showed syptoms that can be credited to the exposure
59
null hypothesis
the exposure is not related to the disease, is 1
60
alternatie hypothesis
if the null hypothesis prove implausible, exposure IS associated with disease
61
ODDS =/ probability
62
odds calculation
number of times something happens/something DOES NOT happen
63
probability calculation
number of times something happens/number of times something COULD happen
64
case control calculations
odds
65
Cohort calculations
risks
66
odds ratio =
odds of disease among people exposed/odds ff disease among people not exposed
67
if odds ratio >1
exposure and disease are positively associated - more diseased people exposed)
68
if odds ratio = 1
exposure and disease are not associated
69
if odds <1
exposure and disease are negatively associated, more non-diseased people are exposed
70

HOSA Epidemiology (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions