Pithua

Question 1

Epidemiology is based on what 2 fundamental assumptions?

Answer 1

1. disease does NOT occur at random, rather there are factors/determinants that can increase or decrease the likelihood of disease
2. the factors or determinants can be identified by systematic investigation of populations or subgroups within populations

Question 2

__________ is the study of the distribution and determinants of disease frequency in human/animal populations and the application of this study to control health problems.

Answer 2

epidemiology

Question 3

when studying human or animal populations, the group of subjects have common …

Answer 3

characteristics
such as: geographic location, age, group membership, breed, parity, housing, production levels, etc.

Question 4

how do you measure disease frequency?

Answer 4

counting the number of cases of a disease in a population over a specific period of time

Question 5

What is meant by studying the “distribution” of disease frequency?

Answer 5

how the disease is distributed through the population
Ex: age, sex, socioeconomic status, breed, location, time

Question 6

_________ are factors that cause some individuals to acquire disease and/or factors that prevent some individuals from getting disease. These are also referred to as “exposures”.

Answer 6

determinants

Question 7

What is the first step of the epidemiologic approach?

Answer 7

Make observations – suspect that exposure influences disease occurence

Question 8

What is the second step of the epidemiologic approach?

Answer 8

form specific hypotheses about exposure-disease link

Question 9

what is the third step of the epidemiologic approach?

Answer 9

perform epidemiologic studies to measure the relationship between exposure and disease

Question 10

What is the fourth step of the epidemiologic approach?

Answer 10

judge if the association is valid and casual – factor in: evidence, chance, bias, cofounding, limits of study design, strength of study design

Question 11

what is the fifth/last step of the epidemiologic approach?

Answer 11

evaluate prevention and treatment

Question 12

What are the 2 criteria for a GOOD hypothesis?

Answer 12

1. project expected association between 2 or more measurable variables
2. carry clear implications for testing stated relations

Question 13

__________ are important for advancing epidemiologic research and guiding study design, variable selection, sample selection, data analyses, and interpretation of results.

Answer 13

hypotheses

Question 14

“Smoking causes cancer” is an example of what type of hypothesis?

Answer 14

fundamental

Question 15

“People who smoke cigarettes daily have a higher incidence of lung cancer over a 10-year period than people who do not smoke cigarettes” is an example of what type of hypothesis?

Answer 15

operational

Question 16

T/F: we must know the specific cause of a disease in order to intervene, that is why hypotheses are so important to guide our experiments.

Answer 16

false – we do NOT need to know a specific cause to intervene.

Question 17

This type of epidemiology is described as:
1. describes patterns of disease
2. monitor public health, evaluate success of disease intervention programs, generate hypotheses about causes of disease, and monitor herd health
3. identify and count cases of disease in populations and conduct simple studies

Answer 17

descriptive epidemiology

Question 18

This type of epidemiology is described as:
1. search for disease cause and prevention
2. evaluate hypotheses about causes of disease and evaluate success of intervention programs
3. compare groups and systematically determine if there is an association present

Answer 18

analytical/scientific epidemiology

Question 19

what are the 3 main uses of descriptive epidemiology in veterinary medicine and public health?

Answer 19

1. ID problems, trends, and high-risk groups
2. planning: where to spend resources
3. generate hypotheses for analytical epidemiology

Question 20

what is the limitation of descriptive epidemiology?

Answer 20

cannot identify cause of disease

Question 21

what are the 4 components for measuring disease frequency?

Answer 21

1. population
2. cases of disease (numerator)
3. size of population (denominator)
4. time

Question 22

A ______ population is a population whose membership is defined on the basis of some event and membership is permanent (ex. veteran of vietnam war or people born in 1982)

Answer 22

fixed

Question 23

A ________ population is where membership is defined by being in a state or condition, but membership is transient. (ex. being a student at a certain school, being a parent of a teenager)

Answer 23

dynamic

Question 24

What are some examples of methods of disease ascertainment?

Answer 24

clinical records
diagnostic tests
disease registries
surveillance programs
self-reports

Question 25

What factor is necessary to compare disease across populations?

Answer 25

size of the population you sampled from. you cannot compare the number of cases alone

Question 26

When measuring disease frequency, this type of measure is the division of one number by another and these numbers do NOT have to be related.

Answer 26

ratio
ex. observed # cases of rabies in bburg during aug / expected # cases of rabies in bburg during aug
if there were 40 cases but you expected 20, then the ratio is 40/20 or 2. This means that there were 2 times as many cases of rabies in bburg during august than was expected.

Question 27

From june to august, you collected 1000 blood samples from dogs at your clinic. 120 of them were positive for Lyme disease. What is the proportion of patients infected with lyme?

Answer 27

12% of patients were infected with lyme.
120/1000 = 0.12

Proportion is the division of two RELATED numbers in which the numerator is a SUBSET of the denominator.

Question 28

You analyze data and determine that there are 100 cases of rabies per 100,000 cats per year.
What is the rate of rabies in cats per year?

Answer 28

Rate is the division of one number by another in which TIME is an intrinsic part of the denominator.
Therefore, rate is the # of NEW cases of rabies among 100,000 cats over a one year period.
So, 100 cases/100,000 cats per year.

Question 29

_________ measures the presence of EXISTING cases of disease in a population during a specific time period.
The denominator will include the TOTAL population (healthy, sick, etc.) and it is the proportion of the population of HAVE the disease.

Answer 29

Prevalence

Question 30

___________ is the proportion of a population that has the disease at a single point in time.

Answer 30

point prevalence

Question 31

What is the prevalence of bordetella in Blacksburg if 89 dogs test positive for bordetella on January 1st? Note, the total population of dogs in bburg is 40,000 on Jan 1st.

Answer 31

0.002

Question 32

You have a clinic with 25 canine patients. On monday, 5 of them have upper respiratory signs. By thursday, 3 have recovered. On saturday, they have all recovered. What is the prevalence of upper respiratory infection on thursday? what about saturday?

Answer 32

thursday – 2/25
saturday – 0

Question 33

_________ measures the occurrence of NEW cases of disease in a population during a specific time period. This involves TRANSITION from one state to another (healthy –> ill, alive –> dead). The denominator only includes the population AT RISK (excludes those who are already measured and/or immune).

Answer 33

incidence

Question 34

What are 2 reasons for measuring prevalence?

Answer 34

1. assess burden of disease (plan & allocate resources)
2. used for research when incidence is difficult to measure (uncertain onset)

Question 35

What are 3 reasons for measuring incidence?

Answer 35

1. etiologic research – find the cause of the dz
2. evaluate preventions – are they working?
3. evaluate treatment – is it working to improve survival or QOL?

Question 36

___________ incidence is when time is described in words that go along with the number. This measures the occurrence of NEW cases of disease in a population during a specified time period, assuming you have a fixed population/ no loss to follow-up.

Answer 36

cumulative

Question 37

___________ measures SPEED at which NEW cases of disease occur within a population. Time is an intrinsic part of the denominator. It does NOT assume the group being observed has been followed the entire time period.

Answer 37

incidence rate

Question 38

You have a clinic with 25 canine patients. On monday, 5 of them have upper respiratory signs. By thursday, 3 have recovered. On saturday, they have all recovered. What is the cumulative incidence of upper respiratory infection throughout the week?

Answer 38

5/25 = 20%

Question 39

__________ is a special type of cumulative incidence that measures the proportion of individuals exposed to an infectious agent who become infected over a certain time period.

Answer 39

attack rate

Question 40

________- is a special type of cumulative incidence that measures the proportion of individuals with a disease who die of that disease.

Answer 40

case fatality rate

Question 41

What are the biggest limitations of measuring cumulative incidence?

Answer 41

1. not a perfect measure in a dynamic population or in a fixed population that loses members over time.
2. doesnt consider time of occurrence

Question 42

What is a person-time?

Answer 42

the amount of time each person AT RISK is under observation. this is the unit of measure for incident rate.

Question 43

You followed 30,330 dogs from 1999-2004. There were 2,314 cases of bordetella during follow-up. What is the incidence rate?

Answer 43

Incidence rate is: # new cases during this time period / total person-time of observation in population at risk

IR = 2,314 / 104,574 = 0.022/PY = 2,215/100,000 PY
during 1999-2004, the incidence rate of bordetella was 2,215/100,000 PY.

Question 44

T/F: to be a prevalent case, an individual has to have been an incident case at some point and must still have the disease so that duration is involved

Answer 44

true

Question 45

What formula can you use to estimate the average duration of a disease?

Answer 45

D = P / IR
P is prevalence
IR is incidence rate (PY)

Question 46

What would happen to the incidence of rabies if you introduced primary prevention efforts to reduce exposure to rabies?
(increase, or decrease, or no effect)

Answer 46

incidence would decrease

Question 47

What would happen to the prevalence of rabies if you introduced primary prevention efforts to reduce exposure to rabies?
(increase, or decrease, or no effect)

Answer 47

prevalence would decrease

Question 48

What would happen to the incidence of FIP if you introduced new treatment that prolongs the life of patients with FIP?
(increase, or decrease, or no effect)

Answer 48

there would be NO effect on incidence because the cases are going to occur regardless of treatment

Question 49

What would happen to the prevalence of FIP if you introduced new treatment that prolongs the life of patients with FIP?
(increase, or decrease, or no effect)

Answer 49

the prevalence would increase because you are not preventing cases from occurring, you are only treating them and prolonging their lifespan with disease.

Question 50

Which type of disease frequency is the following:
The % of dogs that contract influenza during the course of an outbreak (June 1-15, 2022).
A. prevalence
B. incidence rate
C. cumulative incidence

Answer 50

C. cumulative incidence

Question 51

Which type of disease frequency is the following:
The % of potential breeding dogs rejected from service dog breeding program because of poor hip conformation.
A. prevalence
B. incidence rate
C. cumulative incidence

Answer 51

prevalence

Question 52

Which type of disease frequency is the following:
The number of UTIs diagnosed in 1,000 person-years within a veterinary hospital.
A. prevalence
B. incidence rate
C. cumulative incidence

Answer 52

incidence rate

Question 53

Which type of disease frequency is the following:
The % of live-born foals with flexural deformities among 100,000 live births.
A. prevalence
B. incidence rate
C. cumulative incidence

Answer 53

prevalence

Question 54

T/F: the total population contributes to the denominator of cumulative incidence

Answer 54

false – only population at risk

Question 55

T/F: when you calculate incidence rate of disease, you are required to follow subjects for the same amount of time

Answer 55

false

Question 56

_____________ is a device or procedure with the ability to differentiate a diseased individual from a non-diseased individual

Answer 56

diagnostic test

Question 57

Diagnostic tests are used for what type of patients in order to confirm a diagnosis, assess the severity of a disease, determine a prognosis, and assess the progress/response to treatment?

Answer 57

individual sick patients

Question 58

____________ are used in healthy populations or individuals to detect carriers or subclinical disease. They are commonly used in disease control and prevention, detection and monitoring, as well as eradication programs.

Answer 58

screening tests

Question 59

A test is considered useful if the result …

Answer 59

has the potential to alter your diagnosis or course of treatment/action.

Question 60

Necropsy, bacteria culture, exploratory sx, and biopsies are considered “gold standard” tests that are accurate in determining presence or absence of disease. The downside to these tests are …

Answer 60

1. complex
2. costly
3. risky
4. time-consuming

Question 61

T/F: when evaluating a new diagnostic test, we gather data comparing the results of the gold standard test against the results of the new test. The sample population (group that the test was evaluated with) should reflect the target population (group that you will be using test in real life).

Answer 61

true

Question 62

_________ is the proportion of all animals sampled that TRULY HAVE the disease.
In the 2x2 table, this is a+c / (a+b+c+d)
(test pos + dz pos / total tested)

Answer 62

true prevalence.

Question 63

_________ is the proportion of all animals sampled that appear to be infected based on a positive result from the test kit.
In the 2x2 table, this is *a+b / (a+b+c+d)
(total test pos / total)

Answer 63

apparent prevalence

Question 64

When comparing a new diagnostic test and the gold standard test, if the apparent prevalence is LESS than true prevalence, what conclusion can you draw?

Answer 64

the new test is underestimating prevalence of disease.

Question 65

__________ is the true positive rate or the proportion of truly diseased animals that test positive using the test kit.
In the 2x2 table, this is a / (a+c)
(test pos and dz pos / total that have dz)

Answer 65

sensitivity

Question 66

________ is the true negative rate or the proportion of truly uninfected animals that test negative using the test kit.
In the 2x2 table, this is d / (b+d)
(test neg and dz neg / total that do not have dz)

Answer 66

specificity

Question 67

_______ is measuring how close the test results are to the gold standard.

Answer 67

test validity

Question 68

_________ is the proportion of all animals (diseased and non diseased) tested that were CORRECTLY classified by the test kit.
In the 2x2 table, this is (a+d) / (a+b+c+d)
(test pos with dz + test neg without dz) / total)

Answer 68

test accuracy

Question 69

_____________ is assessing the consistency or repeatability of a test. If we repeat a test on the same sample, how often would we get the same answer?

Answer 69

Test precision

Question 70

T/F: if a test is NOT precise, it CANNOT be accurate

Answer 70

true

Question 71

T/F: A test can be very precise, but still inaccurate

Answer 71

true

Question 72

__________ is the probability that a test result reflects the TRUE disease status. I.e. if we get a positive result, how confident are we that this animal is TRULY infected/diseased (PPV) and vice versa (NPV)

Answer 72

predictive value

Question 73

What is the equation to calculate positive predictive value based on the 2x2 table?

Answer 73

a / (a+b)

in other words, the individuals who have disease AND tested positive divided by the total individuals that tested positive.

Question 74

What is the equation to calculate negative predictive value based on the 2x2 table?

Answer 74

d / (c+d)

in other words, the individuals who do NOT have disease AND tested negative divided by the total individuals that tested negative.

Question 75

Positive predictive values are affected by sensitivity and specificity. Choose the correct answer for the following scenarios:
sensitivity: if you have fewer false negatives –> (higher or lower NPV)
specificity: if you have fewer false positives –> (higher or lower PPV)

Answer 75

sensitivity: if you have fewer false negatives –> higher NPV
specificity: if you have fewer false positives –> higher PPV

Question 76

Which of the folllowing can change dramatically and have an impact on predictive values?
a. sensitivity
b. specificity
c. prevalence

Answer 76

c. prevalence

Question 77

If the prevalence of a disease is HIGH, what effect will that have on the positive and negative predictive values?

Answer 77

PPV will be higher – if you get a positive test, you are MORE confident that it is correct due to the disease being more prevalent.

NPV will be lower – if you get a negative test, you are LESS confident that it is correct due to the disease being so prevalent

Question 78

T/F: we can improve positive predictive value by testing only individuals from high risk / high prevalence populations

Answer 78

true
because as prevalence increases, PPV increases

Question 79

T/F: we can improve predictive value by altering sensitivity and specificity through changing the conditions of the test or how it is interpreted (change cut points, etc.)

Answer 79

true
because this will change the threshold for determining whether an animal tests positive or negative

Question 80

T/F: We can improve predictive value of a test by using individual diagnostic tests rather than multiple to make the results more clear.

Answer 80

false
we should do sequential testing or concurrent testing –
do the sensitive test first (to avoid false negatives)
then do a specific test only on the individuals that tested positive on the first test (avoids false positives)

Question 81

T/F: outbreaks are sudden events that occur spectacularly

Answer 81

false – they can be sudden, but they can also be insidious (silent outbreaks)

Question 82

T/F: if you see multiple clinical signs in an individual animal/person, there tends to be a single etiology. And, a single syndrome in a population tends to have multiple etiologies.

Answer 82

true

Question 83

_____________ problems are a combination of errors over time.

Answer 83

additive or cyclic

Question 84

_____________ problems are long-acting errors that require the passage of time before the consequences become of sufficient magnitude to be recognized.

Answer 84

chronic

Question 85

When attempting to determine the problem within an outbreak, you aim to characterize cases in the form of a ____________ which will evolve into a case definition.

Answer 85

working definition

Question 86

In order to verfiy the outbreak, what needs to be confirmed?

Answer 86

is there a true excess of disease – obtain objective data to verify the magnitude of the problem. then, compare the actual number of cases to the expected number to determine if the frequency is “excessive”

Question 87

T/F: if you cannot make a definitive diagnosis, it is not possible to create a case definition

Answer 87

false – you can!
if there is a def dg, it looks like this: pasteurella pneumonia in recently weaned calves
if there is not a def dg, it looks like this: acute respiratory disease in recently weaned calves

Question 88

T/F: a case definition is good because it usually establishes the pathologic or etiologic diagnosis, but it does not solve the producers problems.

Answer 88

true
it does not solve anything because the real question is WHY the problem is occurring.

Question 89

How do you calculate an attack rate?

Answer 89

individuals with dz / # individuals exposed

Question 90

How do you calculate a risk ratio?

Answer 90

incidence risk in exposed / incidence risk of unexposed

Question 91

How do you calculate attributable fraction?

Answer 91

AF = Re - Ro / Re

Re is a/a+b
Ro is c/c+d

Question 92

why do we describe an outbreak according to place?

Answer 92

Because different groups or pens of animals often have different levels of exposure. we want to figure out the affected versus unaffected animals and their location to see if it gives us clues

Question 93

What 2 things do we want to consider when we are describing an outbreak according to time?

Answer 93

1. when (in calendar time) did the problem begin
2. what is the pattern of performance over time

Question 94

What are pseudoepidemics?

Answer 94

onset of producer awareness of a more chronic problem

Question 95

Describe a common point source epidemic curve

Answer 95

many cases during during/around one time period pointing towards a common source being the issue.

Question 96

Describe a continuous source epidemic curve

Answer 96

cases are not just appearing one time, they are continually appearing indicating that continual exposure to the source.

Question 97

Describe a propagated epidemic curve

Answer 97

you see several case peaks over time with a common source but resulting from person to person spread, not as a result of the source just being present.

Question 98

T/F: you should generate your hypothesis about the nature of exposure BEFORE you develop quantitative information (who, when, where, etc.)

Answer 98

false – quantify first, then generate a hypothesis

Question 99

how can you implement interventions as a part of your outbreak investigation?

Answer 99

1. give hands-on practical advice on how to decrease the impact of this problem
2. monitor progress to make sure the intervention is working
3. write written reports of your findings

Question 100

if you want to compute a measure of effect, what measure of disease frequency should you use?

Answer 100

you should use an absolute comparison: risk/rate difference

Question 101

If you calculate a relative comparison such as a risk ratio, rate ratio, and/or an odds ratio, what is this comparison called?
hint: a measure of __________.

Answer 101

measure of association

Question 102

___________ measures such as risk ratio or odds ratio describe the strength of a causal relationship between exposure and the disease.

Answer 102

relative measures

Question 103

A study is considered “valid” ONLY when what 3 alternative explanations have been eliminated?

Answer 103

1. bias
2. confounding
3. random error

Question 104

________ is a systematic error in the design or conduct of a study that results in an erroneous association between the exposure and the disease or obscures an association that actually exists.

Answer 104

bias

Question 105

_________ is mixing of effects between exposure, disease, a confounder. it distorts the relationship between an exposure and disease.

Answer 105

confounding

Question 106

__________ is the probability that an observed study result is due to chance (no assignable cause).

Answer 106

random error

Question 107

T/F: is bias, confounding, and random error are ruled out as alternative explanations of an observed exposure-disease association, then the association is true and the study is “internally valid”

Answer 107

true

Question 108

T/F: if a study has demonstrated an association between an exposure and a disease, then you can assess whether the exposure caused the disease.

Answer 108

false – only after the observed study is considered VALID is it appropriate to assess whether the exposure has caused the disease.
you have to establish internal validity before you could apply to a generalized population.

Question 109

__________ is when the observed results accurately reflect the true association.

Answer 109

internal validity

Question 110

__________ is error due to a recognizable source.

Answer 110

systematic error

Question 111

T/F: it is possible to have both random and systematic error occurring at once.

Answer 111

true

Question 112

If the direction of a bias is TOWARDS the null
(RR=1 or RD=0), then it means the bias is …

Answer 112

masking an association that is truly present
aka it is underestimating the true measure of association

Question 113

_________ is when the observed effect is HIGHER than the true value.

Answer 113

positive bias

Question 114

________ is when the observed effect is LOWER than the true value.

Answer 114

negative bias

Question 115

If the direction of a bias is AWAY from the null, then it means the bias is …

Answer 115

overestimating the true measure of association.
ex. overestimating the effectiveness of a vaccine or overestimating the risk of drinking alcohol on liver failure

Question 116

If an exposure RR is greater than the null (1), what does this indicate about exposure?

Answer 116

exposure increases the risk of the outcome
ex. drinking alcohol increases risk of liver failure

Question 117

If an exposure RR is less than 1, what does this indicate about the exposure?

Answer 117

exposure decreases the risk of the outcome
ex. vaccines (are protective against dz)

Question 118

T/F: if you detect bias in your study, you can correct it before you continue

Answer 118

false – little can be done to correct or remove bias once it has occurred so it should be carefully avoided when designing and conducting a study

Question 119

___________ is a design method to deal with confounding that limits the study to people who are WITHIN one category of the confounder
(ex. only selecting individuals of the same sex or age)

Answer 119

Restriction

Question 120

T/F: restriction is a good way to deal with confounding, however it does limit the sample size, which limits generalizability, and it is possible that incomplete control occurred and residual confounding is present.

Answer 120

true

Question 121

________ is a design method to deal with confounding that selects study subjects so that confounders are distributed identically among exposed and unexposed or cases and controls. For example, if your potential confounding variables are age and sex, then your cases are 35yo males, then your controls should also be 35yo males.

Answer 121

Matching

Question 122

_________ is a design method to deal with confounding in which participants are allocated to treatment groups by a random method that gives EQUAL chance of being in any treatment group. This ensures baseline comparability of groups and controls for unknown and known confounders (with no limit).

Answer 122

randomization

Question 123

Which type of bias can be (to some extent) adjusted or controlled for in the analysis?

Answer 123

confounding

Question 124

_______ bias has to do with WHO gets into your study and results from the procedures used to select subjects. Essentially, it arises when/if people who agree to take part in the study are different from the source population you want to study, and therefore the study population will NOT represent the source population.

Answer 124

selection bias

Question 125

in what studies is selection bias MOST likely to occur in?

Answer 125

1. case control studies
2. retrospective studies
   because outcomes and exposures have already occurred when you are selecting the subjects.
3. experimental cohort studies
4. prospective cohort studies
   due to differential loss to follow-up

Question 126

If you select participants of a study in a manner related to developing the outcome of interest OR participation of individuals if differs for exposure and disease, what will occur in your study?

Answer 126

selection bias
you will get an Risk Ratio estimate that is NOT consistent with the truth as a consequence of how you selected individuals to investigate

Question 127

What is the healthy worker effect?

Answer 127

it is when you select the general population as a comparison group in an occupational cohort study

Question 128

__________ bias occurs if controls are MORE or LESS likely to be selected if they are exposed or unexposed. It occurs when controls fail to represent the exposure distribution in the source population from which the cases arose because controls do not accurately represent the same source population as the cases.
For example, if you are attempting to determine if SES is assoc. with prostate cancer – if your exposed pop is men with prostate cancer, but your control group is individuals from a door-to-door survey during a workday, then you have control-selection bias because unemployed or retired men are mostly at home during those hours (not representative of a true control sample).

Answer 128

control-selection

Question 129

What is the equation to calculate odds ratio?

Answer 129

OR = AD / BC

this is comparing the exposed to the unexposed

Question 130

If your research question aims to determine if women who took antidepressants during pregnancy increases their risk of having babies with birth defects, what could a potential differential participation/self-selection bias be?

Answer 130

that mothers who took antidepressants during pregnancy are MORE willing to participate in this study vs other mothers.

Question 131

How can you prevent differential participation/self-selection bias in your case-control studies?

Answer 131

have a high participation rate for ALL groups

Question 132

If your controls have an unusually LOW prevalence of the exposure, then “b” in in 2x2 table will tend to be smaller. This will bias the odds ratio (toward or away) from 1?

Answer 132

AWAY

it will OVER-estimate the odds ratio

Question 133

If your controls have an unusually HIGH prevalence of the exposure, then “b” in in 2x2 table will tend to be large. This will bias the odds ratio (toward or away) from 1?

Answer 133

TOWARD

it will UNDER-estimate the odds ratio

Question 134

___________ occur when study participants exit the study for reasons related to both exposure and disease

Answer 134

differential loss-to-follow up

Question 135

_________ is bias that can occur if study participants are placed into the wrong exposure or disease category

Answer 135

measurement/misclassification error

Question 136

Non-differential/ random measurement/misclassification errors are about the same in both groups and tend to have what effect on the true difference between the groups

Answer 136

dilute/mask/obscure

Question 137

A ____________ measurement/misclassification error is when information is better in one group than another and the association may be over or under estimated.

Answer 137

differential/non-random

Question 138

____________ bias is error that can occur if the information you collect from or about study participants is erroneous

Answer 138

information

Question 139

__________ bias is a type of information bias that is error occurring when people with disease remember/recall/report their exposure differently (more or less likely).

Answer 139

recall

Question 140

How can you resolve/prevent information recall bias?

Answer 140

use controls who are also diseases to promote comparable recall.
use standardized, close-ended questionnaries to promote consistency and specificity
examine pre-existing data

Question 141

_________ bias is a type of information bias that occurs if there is a systematic difference in soliciting, recording, or interpreting information or control status. In other words, the person recording/interpreting information is influenced by the participants treatment or exposure status.

Answer 141

interviewer

Question 142

How can you prevent interviewer information bias?

Answer 142

use blinding/masking to prevent interviewers from seeing the hypothesis or knowing someones exposure status
use high qual standardized closed ended questionnaire to promote consistency and specificity
examine pre-existing data

Question 143

If your research question wants to determine an etiology, which study designs are BEST to carry out?

Answer 143

1. cohort
2. case-control

Question 144

If your research question wants to determine the effect of a treatment, what study design is BEST to use?

Answer 144

randomized controlled trial

Question 145

if your research question wants to determine the prognosis of a exposure, what study design is BEST to use?

Answer 145

cohort

Question 146

if your research question wants to determine the harm/effect of an exposure, what study designs are BEST to use?

Answer 146

1. cohort
2. case-control

Question 147

if your research question wants to determine a diagnosis, what study designs are BEST to use?

Answer 147

1. cross-sectional
2. case-control

Question 148

A well-built clinical research question has what 4 architectural components?
hint: the abbreviation is PICO

Answer 148

1. patient or population (specific group of interest)
2. intervention/exposure
3. comparison intervention/exposure (control group)
4. outcome

Question 149

If the investigator assigns exposures, what kind of study are your performing – experimental or observational?

Answer 149

experimental

Question 150

if the investigator is performing an experimental study and chooses to do random allocation, what is this study design called?

Answer 150

randomized controlled trial (RCT)

Question 151

If the investigator does NOT assign exposures, this is an observational study. If within this observational study, the investigator includes a comparison group, what type of study does this become?

Answer 151

analytical study

(as opposed to a descriptive study that would NOT have a comparison group)

Question 152

What analytical study looks at the exposure before looking at the outcome?

Answer 152

cohort study

Question 153

What analytical study looks at the outcome first then the exposure?

Answer 153

case-control study

Question 154

What analytical study looks at the exposure and outcome at the same time?

Answer 154

cross-sectional study

Question 155

T/F: a descriptive study investigates and describes the distribution of disease within a population by using routinely collected data (person, place, and time) and attempts to explain what is driving the outcome.

Answer 155

false – all is true except the explanation of the outcome. this study simply outlines the data.

Question 156

__________ studies are analytical studies that describe disease frequency in different populations in relation to exposures within those populations.

Answer 156

ecological

Question 157

A _____________ study gathers information from individuals to measure prevalence at one point in time of the individuals exposed vs the unexposed individuals.

Answer 157

descriptive cross sectional study

Question 158

what is the difference between a descriptive cross sectional study and an analytical cross sectional study?

Answer 158

analytical goes one step further to calculate a prevalence ratio between the 2 prevalences.
So, it calculates the prevalence of the exposed / prevalence of unexposed.

Question 159

what is the starting point for a case-control study?
what about a cohort study?

Answer 159

case-control studies starts with a group of individuals WITH the disease/outcome AND a control-group.

cohort studies define a group of people by their exposure status and then follow them over time to see which individuals develop the disease to compare the incidence of disease.

Question 160

which study design is best for studying multiple exposures?

Answer 160

case-control

Question 161

which study design is best for measuring time relationship between exposure and outcome?

Answer 161

cohort

Question 162

which study design is best for the direct measurement of incidence?

Answer 162

cohort

Question 163

which study design is best for investigations with long latent periods?

Answer 163

case-control