Brainscape's Knowledge GenomeTM

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


See full index

PCM > PCM > Flashcards

PCM Flashcards

1
Q

The study of the distribution and determinants of disease frequency in populations and the application of this study to control health problems.

A

epidemiology

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

A range of values on either side of the odds ratio or point estimate

A

CI confidence interval

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

Used to determine if the observed differences between groups (such as ill and not ill) are significant or due to chance

A

p-value

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

What is a statistically significant p-value?

A

a p-value of less than or equal to 0.05 is statistically significant. The result is not likely attributable to chance.

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

What is the possible range of a p-value?

A

p-values range from 0-1

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

What is a statistically significant CI? (Or, what is a CI that is not statistically significant)

A

A CI that includes 1 is not statistically significant

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

What is a 95% CI telling you?

A

We are 95% confident that the true value lies in this range.

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

This measures new cases developing over a period of time

A

incidence

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

This measures existing cases at a particular point in time or over a previous period of time

A

prevalence

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

(# of new problems during a given period of time)/(total population at risk)

A

incidence

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

(# of patients with the problem at a designated time)/(total population at that time)

A

prevalence

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

This is used to compare risk in two different groups of people, for example risk of heart disease in smokers and nonsmokers.

A

relative risk

risk of disease in exposed/risk of disease in unexposed

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

This is the risk of a group developing a disease over a period of time

A

absolute risk

risk of disease in exposed - risk of disease in unexposed

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

incidence rate 1/incidence rate 2

A

rate ratio

used to determine the probability of a certain event, e.g. crude birth rate

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

ad/bc

[same thing as (a/b)/(c/d)]

A

odds ratio

odds of developing the disease in exposed is X times the odds of developing the disease in unexposed

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

If a pregnancy test is 99% _______ and the test result is negative, you can be nearly certain they are not pregnant.
(sensitive, specific)

A

sensitive

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

If an HIV test is 99% _______ and the test result is positive, you can be nearly certain they actually have HIV.
(sensitive, specific)

A

specific

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

A very sensitive test rules ___ disease when the result is ________.
(in, out/positive, negative)

A

A very sensitive test rules out disease when the result is negative.

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

A very specific test rules ___ disease when the result is _______.
(in, out/positive, negative)

A

A very specific test rules in disease when the result is positive.

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

If you get a positive test result, the probability that the person really does have the disease

A

positive predictive value

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

What is the difference between effectiveness and efficacy?

A

An EFFECTIVE treatment provides positive results in a usual or routine clinical care condition that may not be controlled for research purposes.
An EFFICACIOUS treatment provides positive results in a controlled experimental research trial.

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

What is the ‘number to treat’?

A

the NNT is the average number of patients who need to be treated in order to prevent one additional bad outcome

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

What are the characteristics of an ideal screening test?

A

100% specific, 100% sensitive

  • reasonable cost, safe to administer
  • disease has a widely available treatment with a potential for cure that increases with early detection
  • can detect high proportion of disease in its preclinical state
  • disease is a public health problem (common condition, significant morbidity & mortality)
  • will lead to improved health outcomes
  • test is widely available
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the difference between screening and diagnostic tests?

A

Screening: primary or secondary prevention when patients are asymptomatic but at risk
Diagnostic: test is done when patient is suspected of having a disease and test will confirm

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

What is the procedure for parallel screening tests?

A

Two screening tests are performed at the same time and the results are combined

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

What is the procedure for serial screening tests?

A

Second test is performed only if the first test was positive

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

What is the difference in effect on sensitivity and specificity for parallel and serial screening test strategies?

A

parallel: raises sensitivity, lowers specificity overall
serial: lowers sensitivity, raises specificity overall

28
Q

What is the difference between background and foreground questions?

A

BACKGROUND questions ask for general knowledge about an illness, disease, condition, process or thing. These types of questions typically ask who, what, where, when, how & why about things like a disorder, test, or treatment, etc.
FOREGROUND questions ask for specific knowledge to inform clinical decisions. These questions typically concern a specific patient or particular population. Foreground questions tend to be more specific and complex compared to background questions. Quite often, foreground questions investigate comparisons, such as two drugs, two treatments, two diagnostic tests, etc. Foreground questions may be further categorized into one of 4 major types: treatment/therapy, diagnosis, prognosis, or etiology/harm.

29
Q

What 3 factors are integrated in Evidence-based Medicine?

A
  1. best external evidence
  2. individual clinical expertise
  3. patient values & expectations
30
Q

What is the PICO format for formulating foreground questions?

A

P: patient problem or population (who is the patient, what problem is being addressed)
I: intervention (what is the intervention or exposure)
C: comparison (what is the comparison group)
O: outcome (what is the outcome or endpoint)

31
Q

What is the 2x2 table?

A

………………….disease yes….disease no
exposure yes………A………………B
exposure no……….C……………….D

32
Q

What is internal validity?

A

Internal validity is the extent to which a causal conclusion based on a study is warranted. The study basics, did they minimize bias, were there confounding factors.

33
Q

What is external validity?

A

External validity is the extent to which a study’s results can be applied to populations/situations/etc. different from those in the study. In other words, can you generalize the study findings from the research population to other groups/situations?

34
Q

What is statistical power?

A

the probability that the test will reject the null hypothesis when the null hypothesis was false - the probability of not making an error…
(Error is either getting results that show an association between disease and exposure but there is not truly an association or getting results that show there is no association and there truly is one.)

35
Q

This is an error in interpretation of results due to other unmeasured factors

A

confounding

36
Q

What are four ways to minimize confounding?

A
  1. RESTRICT/STRATIFY the study subjects narrowly (e.g. narrow age range or women only)
  2. MATCH subjects on important potential confounders - assures the comparison groups are the same
  3. RANDOMIZE (intervention/RCT only) - this attempts to produce comparison groups that are similar on both known and unknown confounders
  4. MATH, aka regression techniques
37
Q

What are three ways to minimize bias?

A
  1. randomize
  2. blinding
  3. double-blinding
38
Q

What is bias?

A

systematic error that causes incorrect interpretation of results

39
Q

What are two types of bias?

A

selection bias

information bias

40
Q

What is the primary source of selection bias in case-control studies?

A

the manner in which cases, controls, or both are chosen

41
Q

What is the primary source of selection bias in cohort studies and clinical trials?

A

loss to followup, withdrawal from study, or non-response

42
Q

What is the primary source of selection bias in cross-sectional studies?

A

selective survival (one of the groups, exposed or unexposed, survives longer than the other)

43
Q

In this type of study, a set of observations is collected from all subjects at a certain point in time…a “snapshot”

A

cross-sectional

44
Q

In this type of study, subjects are chosen based on confirmed DISEASE and certain exposures are observed to see if there is a causal relationship

A

case-control

45
Q

In this type of study, subjects are chosen based on their EXPOSURE and observed to see if they develop the disease in order to determine risk factors for a disease

A

cohort

46
Q

In this type of study, an intervention (e.g. medication, device) is chosen and tested to see if it works. Gold standard of evidence.

A

clinical trial

47
Q

What is a prospective study?

A

A prospective study watches for outcomes, such as the development of a disease, during the study period and relates this to other factors such as suspected risk or protection factor(s). The study usually involves taking a cohort of subjects and watching them over a long period.

48
Q

What is a retrospective study?

A

A retrospective study looks backwards and examines exposures to suspected risk or protection factors in relation to an outcome that is established at the start of the study.
Looks at already-collected data as though it was happening in real time.

49
Q

Study for odds-ratio

A

Case-control study

50
Q

What is randomization and why is it important?

A

Subjects get randomly put into different arms of the study - it reduces bias.

51
Q

Study for NNT

A

RCT/Clinical trial

52
Q

Studies that can be used to calculate relative risk

A

Cohort, RCT/Clinical trial

53
Q

What is information bias?

A

bias arising from measurement error

54
Q

What is selection bias?

A

bias arising from the way the subjects are identified and selected for the study

55
Q

What would make your CI narrower?

A

larger sample size

56
Q

What are the 2 definitions of p-value?

A
  1. the probability that we make a type I error (falsely reject the null hypothesis)
  2. the probability that the difference we saw between the groups happened by chance alone
57
Q

What is the formula for sensitivity?

A

True positive/(true positive + false negative)

58
Q

What is the formula for specificity?

A

True negative/(false positive + true negative)

59
Q

the proportion of people WITH THE DISEASE that the test correctly identified as positive

A

sensitivity

60
Q

the proportion of people WITHOUT THE DISEASE that the test correctly identified as negative

A

specificity

61
Q

Use this test for screening

A

highly sensitive test

62
Q

Use this test for confirming a diagnosis

A

highly specific test

63
Q

What is the formula for positive predictive value?

A

true positive/(true positive + false positive)

64
Q

What is the formula for negative predictive value?

A

true negative/(true negative + false negative)

65
Q

If you get a negative test result, the probability that the patient really doesn’t have the disease

A

negative predictive value

66
Q

What is the difference between nominal and ordinal variables?

A

Nominal: has two or more categories, but there is no intrinsic ordering to the categories. For example, gender is a nominal variable having two categories (male and female) and there is no intrinsic ordering to the categories. Hair color is also a nominal variable having a number of categories (blonde, brown, brunette, red, etc.) and again, there is no agreed way to order these from highest to lowest.
Ordinal: there is a clear ordering of the variables. e.g. elementary school, junior high, high school; excellent, average, poor; etc.

67
Q

What is an ecologic fallacy?

A

The ecological fallacy occurs when you make conclusions about individuals based only on analyses of group data. For instance, assume that you measured the math scores of a particular classroom and found that they had the highest average score in the district. Later (probably at the mall) you run into one of the kids from that class and you think to yourself “she must be a math whiz.” Aha! Fallacy! Just because she comes from the class with the highest average doesn’t mean that she is automatically a high-scorer in math. She could be the lowest math scorer in a class that otherwise consists of math geniuses!

PCM (1 decks)

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