Brainscape's Knowledge GenomeTM

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


See full index

Behavioral Science > Epidemiology/Biostatistics > Flashcards

Epidemiology/Biostatistics Flashcards

1
Q

What are the different types of studies?

A
  • Case control
  • Cohort
  • Cross-sectional
  • Twin concordance
  • Adoption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What type of study is a Case-control?

A

Observational & retrospective

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

What is the design of a case-control?

A
  • Compares a group of people w/ dz to a group w/o dz
  • Looks for prior exposure or RF
  • Asks, “what happened?”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What do Case-control studies measure?

A

Odds ratio (OR)

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

What is an example of a case control study?

A

Pts w/ COPD had higher odds of a hx of smoking than those w/o COPD had

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

What type of study is a Cohort study?

A

Observational & prospective or retrospective

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

What is the design of a Cohort study?

A
  • Compares a group w/ a given exposure or risk factor to a group w/o such exposure
  • Looks to see if exposure inc the likelihood of dz
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What do Cohort studies measure?

A

Relative risk (RR)

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

What is an example of a Cohort study?

A

Smokers had a higher risk of dev COPD than nonsmokers had

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

What type of study is a Cross-sectional study?

A

Observational

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

What is the design of a Cross-sectional study?

A
  • Collects data from a group of people to assess freq of dz (& related RF) at a particular point in time
  • Asks, “what is happening?”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does a Cross-sectional study measure?

A
  • Dz prevalence
  • Can show RF assoc. w/ dz but doesn’t est causality
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the design of a Twin concordance study?

A

Compares the freq w/ which both monozygotic twins or borh dizygotic twins dev sam dz

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

What do Twin concordance studies measure?

A

Heritability

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

What is the design of an Adoption study?

A

Compares siblings raised by biological vs adoptive parents

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

What do Adoption studies measure?

A

Heritability & influence of environmental factors

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

What is a clinical study?

A

Experimental study involving humans

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

What do clinical trials compare?

A

Therapeutic benefits of 2 or more tx or of tx & placebo

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

What improves the study quality of a clinical trial?

A
  • Randomized
  • Controlled
  • Double-blinded
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is a double blind study?

A

Neither pt nor doctor knows whether the pt is in the tx or control group

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

What is a triple blind study?

A

Refers to the additional blinding of the researchers analyzing the data

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

What is the study sample of a Phase I clinical trial?

A

Small # of healthy volunteers

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

What is the purpose of a Phase I clinical trial?

A

Assess safety, toxicity & pharmacokinetics

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

What is the study sample of Phase II clinical trial?

A

Small # of pt w/ dz of interest

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

What is the purpose of a Phase II clinical trial?

A

Assess tx efficacy, optimal dosing & adverse effects

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

What is the study sample of a Phase III clinical trial?

A

Large # of pt randomly assigned either to the tx under investigation or to the best available tx (or placebo)

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

What is the purpose of a Phase III clinical trial?

A

Compares the new tx to the current standard of care

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the study sample of a Phase IV clinical trial?

A

Postmarketing surveillance trial of pts after approval

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the purpose of a Phase IV clinical trial?

A

Detects rare or LT adverse effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is an Evaluation of dx tests?

A

Uses 2x2 table comparing test results w/ the actual presence of dz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the components of evaluating dx tests?

A
  • TP= True Positive
  • FP= False Postiive
  • TN= True Negative
  • FN= False Negative
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the fixed properties of evaluation dx tests?

A

Sensitivity & specificity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Which properties vary w/ prevalence or pretest probability?

A

PPV & NPV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is Sensitivity (true-positive rate)?

A

Proportion of all people w/ dz who test positive or the probability that a test detects dz when dz is present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What does a value approaching 100% sensitivity mean?

A

Desirable for ruling out dz & indicates a low false-negative rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is sensitivity used for?

A

Screening in dz w/ low prevalence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What does sensitivity do?

A
  • PID= Positive In Dz
  • SNOUT= SeNsitivity rule OUT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is Specificity (true-negative rate)?

A

Proportion of all people w/o dz who test negative or the probability that a test indicates non-dz when dz is absent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What does a value approaching 100% Specificity mean?

A

Desirable for ruling in dz & indicates a low false-positive rate

40
Q

What is specificity used for?

A

Used as a confirmatory test after a positive screening test

41
Q

What does specificity do?

A
  • NIH= Negative In Health
  • SPIN= SPecificty rules IN
42
Q

What is Positive predictive value (PPV)?

A
  • Proportion of + test results that are +
  • Probability that person actually has the dz given a + test result
43
Q

What does PPV vary w/?

A

Directly w/ prevalence or pretest probability

44
Q

What does a high PPV mean?

A

High pretest probability

45
Q

What is Negative Predictive value (NPV)?

A
  • Proportion of negative test results that are true negative
  • Probability that person actually is dz free given a negative test result
46
Q

What does a low NPV mean?

A

High pretest probability

47
Q

What is Incidence rate?

A

# of new cases in a specificed time period

Pop at risk druing same time period

48
Q

What does incidence look at?

A

New incidents

49
Q

What is Prevalence?

A

# of existing cases

Pop at risk

OR

Incidence rate x average dz

50
Q

What does prevalence look at?

A

All current cases

51
Q

Prevalence> incidence for ____ ____.

A

Chronic Diseases

52
Q

What are Odds ratio (OR) used for?

A

Case-control studies

53
Q

What does Odds ratio mean?

A

Odds that the group w/ the dz (cases) was exposed to a RF divided by the odds that the group w/o the dz (controls) was exposed

54
Q

What is Relative risk used for?

A

Cohort studies

55
Q

What does Relative risk mean?

A

Risk of dev dz in th exposed group divided by risk in the unexposed group

56
Q

If prevalence is low ___=___.

A

Relative risk= Odds ratio

57
Q

What is Attributable risk?

A

The difference in risk b/w exposed & unexposed groups or the proportion of dz occurrences taht are attributable to the exposure

58
Q

What is Absolute risk reduction (ARR)?

A

Absolute reduction in risk assoc. w/ a tx as compared to a control

59
Q

of pts who need to be tx for 1 pt to benefit is calculated as ______________.

A

1/absolute risk reduction

60
Q

of pts who need to be exposed to a RF for 1 pt to be harmed is calculated as ___________.

A

1/attributable risk

61
Q

What is precision?

A

Consistency & reproducibility of a test (reliability)

Absence of random variation in a test

62
Q

What is a Random error?

A

Reduces precision in a test

63
Q

Inc precision→ dec ____ ____.

A

Standard deviation

64
Q

What is Accuracy?

A

The trueness of test measurements (validity)

The absence of systematic error or bias in a test

65
Q

What is Systematic error?

A

Reduces accuracy in a test

66
Q

What is Bias?

A

Occurs when there is systemic error or favor in a particular direction

67
Q

What is Selection bias?

A

Nonrandom assignment of participation in a study group

68
Q

What is Recall bias?

A

Knowledge of presence of disorder alters recall by subjects; common in retrospective studies

69
Q

What is Sampling bias?

A

Subjects are not representative of the general pop; therefore results are not generalizable.

A type of selection bias

70
Q

What is Late-look bias?

A

Info gathered at an inappropriate time

71
Q

What is Procedure bias?

A

Subjects in diff groups are not tx the same

72
Q

What is Confounding bias?

A

Occurs when factor is related to both exposure & outcome, but is not on the casual pathway; factor distorts or confuses effect of exposure on outcome

73
Q

What is Lead-time bias?

A

Early detection confused w/ inc survival; seen w/ improved screening

74
Q

What is Observer-expectancy effect?

A

Occurs when a researcher’s belief in the efficacy of a tx changes the outcome of that tx

75
Q

What is the Hawthorne effect?

A

Occurs when the group being studied changes its behavior owing to the knowledge of being studied

76
Q

What are the ways to reduce bias?

A
  • Blind studies to limit influence of participants & researches on interpretation of outcomes
  • Placebo control groups
  • Crossover studies to limit confounding bias
  • Randomization to limit selection bias & confounding bias
  • Matching to reduce confounding bias
77
Q

What are measures of central tendency?

A
78
Q

What are measures of dispersion?

A
  • Standard deviation (SD)
  • Standard error of the mean (SEM)
  • Z-score
  • Confidence interval
79
Q

What is normal distribution?

A

Gaussian, also called bell-shaped

Mean=median=mode

80
Q

What is a Positive skew?

A
  • Mean>median>mode
  • Asymmetry w/ longer tail on right
  • Mode is lease affected by outliers in the sample
81
Q

What is a Negative skew?

A
  • Mean<median>
    </median><li>
    Asymmetry w/ longer tail on left</li>

</median>

82
Q

What is Power (1-ß)?

A

Probability of rejecting null hypothesis when is it in fact false or the likelihood of finding a diff if one fact exists

83
Q

What does Power (1-ß) increase w/?

A
  • Inc sample size
  • Inc expected effect size
  • Inc precision of measurement
84
Q

What is Meta-analysis?

A

Pools data & integrates results from several similar studies to reach an overall conclusion

Inc statistical power

85
Q

What is Meta-analysis limited by?

A

Quality of individual studies or bias in study selection

86
Q

What is a confidence interval?

A

Range of values in which a specified probability of the means of repeated samples would be expected to fall

87
Q

What is a t-test?

A

Checks diff b/w the means of 2 groups

88
Q

What is ANOVA?

A

Checks diff b/w the means of 3 or more groups

89
Q

What is Chi-square (x2)?

A

Test checks diff b/w 2 or more % or proportions of categorical outcoomes (not mean values)

90
Q

What is Pearson’s correlation coefficient (r)?

A
  • r is always b/w -1 & +1
  • The closer the absoulte value of r is to 1 the stronger the linear correlation b/w the 2 variables
91
Q

What is Primary dz prevention?

A

Prevent dz occurrence

92
Q

What is secondary dz prevention?

A

Early detection of dz

93
Q

What is Tertiary dz prevention?

A

Reduce disability from dz

94
Q

What are Medicare & Medicaid?

A

Federal programs that originated from amendments of the Social Security Act

95
Q

Who is Medicare available to?

A

Pts >65yo & <65yo w/ certain disabilities & those w/ end-stage renal dz

96
Q

Who is Medicaid available to?

A

Joint federal & state health assistance for people w/ very low income

Behavioral Science (4 decks)

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