CHS 712- Epidemiology in Public Health Quizzes 1-12
Arrange the eras of epidemiology into the correct chronological order. *Era of infectious disease epidemiology *Era of sanitary reform *Era of chronic disease epidemiology *Emergent era
*Early 1900s *Late 1800s *Late 1900s *21st century
Match each era with its causal paradigm: * Era of chronic disease epidemiology * Era of infectious disease epidemiology *Era of sanitary reform Emergent era
*Web of Causation * Causes, consequences, prevention and treatment of disease *Miasmatic causes of disease *Eco-Epidemiology, globalism
In a population of 5,000 people, 100 ate spinach contaminated with E. coli (O157:H7) and became ill. Of the ill, 15 died. What was the case fatality rate 20 per 1,000 3 per 1,000 150 per 1,000 15 deaths
150 per 1,000
Reasons for conducting a case-control study instead of a cohort study include which of the following? (Select all that apply.) When the disease is rare When little is known about a disease When the disease has a long induction and latent period
All Apply
The main advantages of using hospital controls in a case-control study include which of the following? (Select all that apply.) Easy identification Less expensive Less recall bias Comparable to cases that come from the same population base
All Apply
"Determinants" of disease include ________. (Select all that apply.) causes of disease preventive factors genetic makeup
All apply
Experimental studies can be classified by which of the following? (Select all that apply.) The unit to which the treatment is assignment Purpose Method of treatment administration Number of treatments being tested
All apply
Major advantages of a case-cross-over study are which of the following? (Select all that apply.) Fewer subjects are needed. Cases and controls have similar characteristics. It is easier to get controls.
All apply
The components of epidemiology include _________. (Select all that apply) frequency and distribution population disease determinants disease control
All apply
Homogeneity of effect means: effect measure modification is absent. the stratum-specific measures of association between an exposure and outcome are nearly the same for each stratum of a third variable. statistical interaction is absent. All of these answers are correct
All of these answers are correct
The main purpose of adjusting death rates for age is to compare mortality across different populations control for differences in the age distributions of populations eliminate the effects of age when comparing populations. All of these answers are correct
All of these answers are correct
Vital statistics refers to the collection of information about divorces and marriages births and deaths fetal deaths All of these answers are correct
All of these answers are correct
An association is considered valid if which the following explanations has been eliminated? Systematic bias Confounding Random error All of these answers are correct.
All of these answers are correct.
Characteristics of a cause include what? Statistical dependence between causal factor and outcome Time order Direction All of these answers are correct.
All of these answers are correct.
Over the years, some definitions of "cause" have included which of the following? "That which produces" "An event that preceded the disease onset" "Something that makes a difference" All of these answers are correct.
All of these answers are correct.
Some ways to minimize misclassification bias include: using multiple measures of exposure and disease. validating collected data. defining exposure and disease using sensitive and specific criteria. All of these answers are correct.
All of these answers are correct.
The criteria of a confounder include: an association with the exposure in the population that produced the cases. an independent risk factor for the outcome of interest. that it cannot be an intermediate step in the pathway between the exposure and disease. All of these answers are correct.
All of these answers are correct.
Which of the following measures can be estimated from a clinical trial? Cumulative incidence Risk difference Risk ratio All of these answers are correct.
All of these answers are correct.
Which of the following should be considered as an alternative explanations for the result of a study? Confounding Bias Random error All of these answers are correct.
All of these answers are correct.
Health risk behaviors of adults in the U.S. are assessed through the National Health and Nutrition Exam Surveys (NHANES) Behavioral Risk Factor Surveillance System National Health Care Surveys. National Health Care Surveys.
Behavioral Risk Factor Surveillance System
The crude death rate can be expressed as the number of deaths divided by the population-at-risk a weighted sum of the age-specific death rates and the proportions of the population by age Neither of these answers is correct Both of these answers are correct
Both of these answers are correct
If you want to find data on global cancer incidence, which would be a likely source of this information? National Health and Nutrition Examination Survey (NHANES) National Health Interview System (NHIS) Surveillance, Epidemiology and End Results System (SEERS) Cancer Incidence on Five Continents
Cancer Incidence on Five Continents
Which of the following study designs begin with people who have a disease? (Select all that apply.) Cohort study Case-control study Therapeutic trial Preventive trial
Case-control study Therapeutic trial
Which study type is the typical design for measuring incidence? Cross-sectional Ecologic Cohort Case-control
Cohort
Which of the following study designs are considered observational studies? (Choose all that apply.) Cohort study Cross-sectional study Clinical trial Case-control study Experimental study Ecologic study
Cohort study Cross-sectional study Case-control study Ecologic study
Repeated observations of a relationship between an exposure and outcome is an example of which of Hill's criteria? Consistency Specificity Coherence Strength of association
Consistency
Which study design is most often used for public health planning? Cross-sectional Ecologic Cohort Case-control
Cross-sectional
What is the most appropriate measure of new-onset disease frequency in an open population? Incidence rate Cumulative incidence Prevalence Odds
Cumulative incidence
Consider the definition of epidemiology—"the study of the distribution and determinants of disease frequency in human populations and the application of this study to control health problems." Which part of this definition is the "domain" of descriptive epidemiology? Distribution of disease Determinants of disease Application Control of health problems
Distribution of disease
What is a common problem of ecologic studies? Confounding Ecologic fallacy Lack of participation Loss to follow-up
Ecologic fallacy
Which of the following is not a strength of case-control studies? Efficient for studying rare diseases Efficient for studying rare exposures Can evaluate multiple exposures Efficient for studying diseases with long induction and latent periods
Efficient for studying rare exposures
What are the major goals of randomization? (Select all that apply.) Ensure treatment assignment occurs in an unbiased way. Mask the participants. Distribute potential confounders evenly across the groups. Increase participation in the study.
Ensure treatment assignment occurs in an unbiased way. Distribute potential confounders evenly across the groups.
What was the signal event of the transition from the era of infectious disease epidemiology to the era of chronic disease epidemiology? Discovery of the tubercle bacillus The AIDS pandemic Discovery of the web of causation Evidence that smoking causes lung cancer
Evidence that smoking causes lung cancer
The principle of equipoise is most important in which kind of study? Cohort Cross-sectional Experimental Case-control
Experimental
A long follow-up period makes it easier to measure outcomes in a cohort study. True False
False
Birth defects usually represent prevalent, rather than incident, cases. True False
False
Cross-sectional studies evaluate associations using the population rather than the individual as the unit of study. True False
False
Epidemiologists agree on the specific steps in the method of causal inference. True False
False
Hill's causal criteria should be used systematically as rigid criteria for establishing causal inference. True False
False
It is important for clinical trials to be conducted within a two-year period. True False
False
It is okay to compare the results of several studies even when the case definition is different across the studies. True False
False
Noncompliance occurs only when the study participants willfully decide to stop taking the study treatment. True False
False
Pancreatic disease is suitable for screening because it is a serious condition. True False
False
Secondary prevention efforts include activities that prevent the onset of disease. You Answered True False
False
Selection bias occurs in a cohort study if loss to follow-up is related to exposure. True False
False
Sensitivity is the probability of correctly identifying someone without disease. True False
False
The term "epidemic" refers only to an infectious disease outbreak. True False
False
When study participants are assigned to the treatment group in alternation assignment, this is considered "random assignment." True False
False
Experimental studies always have less confounding than observational studies. True False
False Confounding occurs in all types of studies.
Differential misclassification always leads to bias toward the null. True False
False Differential misclassification may lead to either a bias toward or away from the null.
It is always impossible to infer temporality from a cross-sectional study. True False
False If the exposure is unalterable—for example, a genetic trait—then temporality can be established.
In a case-control study, it is better to include people who may not have the disease than to exclude people who do have the disease. True False
False Including people who do not have the disease will lead to more classification error in the study. It is better to have a restrictive definition, which restricts people from the study.
Prevalence is most useful for determining the rate and cause of disease. True False
False Prevalence is most useful for understanding the burden of disease in a population and for allocating resources. Incidence rate is most useful for determining the rate of disease, and either incidence measure is useful for determining cause of disease.
The population risk difference is derived by subtracting risk in the unexposed group from risk in the exposed group True False
False The population risk difference is derived by subtracting risk in the unexposed group from risk in the population.
The best way to evaluate effect measure modification is to compare the crude measure of association and the adjusted measure of association. True False
False This is the first step of evaluating a potential confounder. The best way to evaluate effect measure modification is to compare the stratum-specific measures of association.
A risk factor is always the same thing as a cause. True False
False A risk factor does not directly cause a disease but serves to identify more proximate causes.
The direct method of standardization is used when the numbers of deaths in each age group in the study population are too small to calculate stable age-specific rates True False
False The indirect method of standardization is used when the numbers of deaths in each age group in the study population are too small to calculate stable age-specific rates
Intermediate variables in a causal pathway are special types of confounders. True False
False Variables that are part of the causal pathway are not considered to be confounders.
What was Robert Koch's theory of causation based on? Chronic diseases Causes of death Germ Theory Web of causation
Germ Theory
Which of the following diseases meets all the criteria for screening? Pancreatic cancer HIV Flu Pneumonia
HIV
An important work that helped mark the transition from the social reform era to the infectious disease era was the Bradford-Hill Criteria Poor Law Henle-Koch Postulates Malthusian Theory
Henle-Koch Postulates
What is the most appropriate measure of new-onset disease frequency in a fixed population? Incidence rate Cumulative incidence Prevalence Odds
Incidence rate
Which measure of incidence has person-time in the denominator? Incidence rate cumulative incidence Prevalence ncidence proportion
Incidence rate
Which measures of disease frequency focus on measuring the transition from health to disease? (Select all that apply.) Prevalence Incidence rate Mortality rate Cumulative incidence
Incidence rate Cumulative incidence
If the diagnostic criteria of a disease were to change and become stricter than the previous criteria, what would you likely see in the data on this disease? Incidence would increase. Incidence would decrease. Incidence would remain the same.
Incidence would decrease.
In the United States, a graph of the relationship between age and mortality rate is J shaped U shaped normally distributed unpredictable
J shaped
One of the earliest experimental studies on scurvy was conducted by: John Snow John Graunt James Lind William Farr
James Lind
Who conducted a thorough analysis of the water drinking habits to investigate the source of a cholera epidemic in London? John Snow John Graunt James Lind William Farr
John Snow
What is the interval between disease onset and clinical diagnosis? Induction period Latent period Infectious period
Latent period
__________ over-estimates the benefits of screening and should be taken into account when evaluating a screening program. Sensitivity Specificity Information bias Lead-time bias
Lead-time bias
What is the most common source of selection bias in a prospective cohort study? There is no selection bias in a cohort study. Loss to follow-up Incomplete ascertainment of cases Incomplete ascertainment of controls
Loss to follow-up
Which of the following is the principal source of data on the health of the civilian, non-institutionalized population of the United States? National Health and Nutrition Exam Survey (NHANES) Behavioral Risk Factor Surveillance System National Health Care Surveys National Health Interview Survey
National Health Interview Survey
What studies commonly use proportional mortality ratio (PMR) and standardized mortality ratio (SMR) as their measure of association? Case-control studies Occupational cohort studies Experimental studies Cross-sectional studies
Occupational cohort studies
What kind of studies suffer from the see-saw effect? Case-control studies SMR studies PMR studies Cross-sectional studies
PMR studies
Which of the following measures would tend to be larger in the same population? Point prevalence Period prevalence Prevalence rate No differences in any of the measures
Period prevalence
The beneficial effect of an inactive control treatment is known as what? Hawthorne effects Halo effects Placebo effect Sham effect
Placebo effect
The existence of a biological mechanism for a disease caused by a specific exposure is an example of which of Hill's criteria? Consistency Specificity Plausibility Strength of association
Plausibility
Match the type of cohort study with its description. Considered to be less vulnerable to bias because outcomes have not occurred. Considered to be more efficient because less time is needed
Prospective Cohort Retrospective Cohort
What do chronic diseases usually have? Proximate causes Distant causes Proximate and distant causes None of the other answers is correct.
Proximate and distant causes
Which type of case definition leads to fewer classification errors? Restrictive definition Inclusive definition Signs and symptoms definition Self-diagnosis definition
Restrictive definition
Describing disease by person, place, and time is done for what kind of purposes? (Select all that apply.) Scientific Administrative Educational
Scientific Administrative
What are the two major forms of bias in a study? Selection bias and prejudice Information bias and prejudice Selection bias and information bias Confounding and prejudice
Selection bias and information bias
One exposure causing one effect is an example of which of Hill's criteria? Consistency Specificity Coherence Strength of association
Specificity
A "complete causal mechanism" that inevitably produces disease is known as a what? Risk factor Sufficient cause Necessary cause Component cause
Sufficient cause
What causes the "ecologic fallacy"? A false association between exposure and disease Interference from the environment The lack of information at the individual level The inability to assess temporality
The lack of information at the individual level
Retrospective cohort studies should be used when: The outcome of interest has a long induction and latent period. The exposure is rare. The exposure is rare and multiple effects of exposure are of interest. None of the other answers is correct.
The outcome of interest has a long induction and latent period.
Which is the ideal comparison group in a cohort study? The same individuals, had they not been exposed Different individuals, with different exposures Similar individuals, with similar exposures
The same individuals, had they not been exposed
A "general cohort" is assembled to study common exposures True False
True
A "sufficient cause" could also be described as one pathway for getting a specific disease. True False
True
A causal relationship between exposure and outcome must be asymmetrical. True False
True
A relative measure of comparison is based on the ratio of two frequency measures True False
True
A tenet of the sufficient-component causal model is the idea that disease can originate from several different sufficient causes. True False
True
Age is an important personal factor in disease because it reflects both the aging process and previous experiences to harmful exposures True False
True
All high-quality epidemiologic studies include techniques for controlling confounding. True
True
An absolute measure of comparison is based on the subtraction of two frequency measures. True False
True
An age-adjusted death rate is a hypothetical index True False
True
An age-specific death rate is a crude death rate for a specific age group True False
True
An important difference between an observational study and an experimental study is that exposures are assigned to participants in experiments. True False
True
An intent-to-treat analysis would compare everyone who was assigned to Treatment 1 with everyone who was assigned to Treatment 2, regardless of whether they completed the assigned treatment. True False
True
At the beginning of a cohort study, it is important that all participants are free of the outcome of interest. True False
True
Attack rate is a type of cumulative incidence True False
True
Because the time of disease onset is often difficult to identify, the latent period and induction period are usually merged together in a cohort study. True False
True
Case fatality rate is a type of cumulative incidence True False
True
Clinical trials may have both primary and secondary outcomes. True False
True
Cohort studies compare exposed and unexposed, while case-control studies compare diseased and non-diseased. True False
True
Confounding may be accounted for in either the design of the study or analysis of the data. True False
True
Cumulative incidence can be calculated in a clinical trial. True False
True
Cumulative incidence can be obtained from an incidence rate True False
True
Cut-points of screening tests should take into account the seriousness of false positives and false negatives. True False
True
Data from death certificates should be evaluated carefully because inconsistencies may occur when the International Classification of Disease (ICD) codes are changed. True False
True
Eligibility criteria affect the generalizability of an experimental study. True False
True
Examination of a 2x2 table is important because formulas and interpretation may change based on whether exposure status is placed along the side (rows) or along the top (columns). True False
True
Ideas about case-control studies have changed over time, from the thinking that they were less rigorous than cohort studies to the idea that they are just as valid for finding a cause-effect relationship. True False
True
If stratum-specific estimates of a relationship between exposure and outcome are different, we can conclude that the variable on which we are stratifying is an effect measure modifier. True False
True
In confounding, we are interested in whether the measure of association is distorted by a third variable, whereas in effect measure modification, we are interested in whether the measure of association differs across levels of a third variable. True False
True
It is not enough to determine the presence of confounding; an investigator must also determine the magnitude and direction of confounding. True False
True
It is possible to calculate the attributable proportion and the population attributable proportion using an odds ratio (OR). True False
True
John Snow's epidemiologic study of the cause of the London cholera epidemic could be considered a "natural experiment." True False
True
John Snow's theories about the transmission of cholera were disputed for several years after he conducted his famous study in London. True False
True
Lead time can vary from person to person. True False
True
Length-bias sampling occurs because screening tends to identify people with the less aggressive forms of disease. True False
True
Misclassification of exposure or disease may be either differential or nondifferential. True False
True
Modern epidemiology views the case-control study as a method of sampling a population. True False
True
Mortality data are easy to obtain, but the accuracy is often questionable. True False
True
Nondifferential loss to follow-up of diseased participants in a cohort affects the absolute risk but not the relative risk. True False
True
Nondifferential misclassification of dichotomous variables biases results toward the null. True False
True
One indication that effect measure modification is present is that the size of a measure of association changes according to the level of a third variable. True False
True
Prevention trials may be classified as primary prevention trials or secondary prevention trials. True False
True
Primary prevention efforts include activities that prevent the onset of disease. True False
True
RD is the excess risk or rate associated with the exposure True False
True
Recall bias is a form of information bias that occurs when there is a differential level of accuracy in information provided by compared groups. True False
True
Retrospective cohort studies should be used when the outcome of interest has a long induction and latent period. True False
True
SMR studies suffer from the "healthy worker effect." True False
True
Sensitivity and specificity are percentages. True False
True
Sensitivity and specificity of a screening test speak to the validity of the test. True False
True
Spot maps are helpful in showing the geographic distribution of cases but should not be used to assess the risk of disease True False
True
Standardizing to a younger population results in a lower age-adjusted death rate True False
True
Study participants are masked in single-masked, double-masked, and triple-masked studies. True False
True
Tertiary prevention efforts include activities that target people with existing disease. True False
True
The "counterfactual ideal" states that the best comparison group in a cohort study would be the same individuals in the exposed group, had they not been exposed. True False
True
The National Health Care Surveys are a group of surveys that provide information on the use and quality of health care in a number of different settings. True False
True
The best way to minimize bias from misclassification is to improve the accuracy of the collected data. True False
True
The counterfactual ideal is used to guide the selection of a comparison group in order to minimize confounding. True False
True
The criteria for case definitions are different in case-control studies than in other types of epidemiologic studies. True False
True
The crude death rate is a good measure of the overall magnitude of mortality in a population. True False
True
The denominator of prevalence includes people who are sick, healthy, at risk, and not at risk True False
True
The first step in assessing whether a variable is a confounder is to determine the strength of association between the variable and the disease. True False
True
The impact of an exposure on a population is a function of the rate or risk difference (RD) and the proportion of exposed individuals in a population. True False
True
The induction period is the time between the causal action of exposure and the onset of disease. True False
True
The major difference between a community experimental study and an individual experimental study is the unit to which the treatment is assigned. True False
True
The major difference between an experimental study and an observational study is active manipulation of the treatment by the investigator. True False
True
The most commonly used causal criteria proposed by Sir Austin Hill are consistency, strength of association, biological plausibility, and biological gradient. True False
True
The prevalence of a disease is related to the incidence rate and duration of the disease True False
True
The primary objective of analysis in cohort studies is to compare disease occurrence in exposed and unexposed populations. True False
True
The rationale behind using dead controls in a case-control study is for comparability of data collection procedures between cases and controls. True False
True
There are both causal and non-causal associations, and causal inference is a method for distinguishing between the two. True False
True
Using a placebo in clinical trials is one method of masking. True False
True
When comparing death rates in the same population for different years, it is essential to adjust the rates to the same standard population before making a comparison. True False
True
When effect measure modification is present on a relative scale, it is absent on an absolute scale. True False
True
When effect measure modification is present on an absolute scale, it is absent on a relative scale. True False
True
When researchers evaluate whether study results are true, they are really evaluating the internal validity of the study. True False
True
he major disadvantages of using population controls for a case-control study are (1) expense and time needed, (2) difficulty in getting cooperation, and (3) differential recall. True False
True
When examining surveillance data by place, it is better to characterize cases by the place where they were reported rather than by the place of exposure True False
True When examining surveillance data by place, it is better to characterize cases by the place of exposure since this is more relevant to the epidemiology of the disease.
For a case-control study, why is it not important that all cases in a population be identified? (Select all that apply.) Validity should not be sacrificed for generalizability. Generalizability should not be sacrificed for validity. Partial case ascertainment is legitimate as long as the source population can be identified.
Validity should not be sacrificed for generalizability. Partial case ascertainment is legitimate as long as the source population can be identified.
When is a factorial design desired in a clinical trial? When investigators want to test the efficacy of one treatment. When investigators want to test separate and combined effects of several agents. When investigators want to conduct a community trial. When study participants have several risk factors.
When investigators want to test separate and combined effects of several agents.
Of the early key figures in the history of epidemiology and demography, which one is credited with developing the British system for vital statistics? John Snow William Farr John Graunt Edwin Chaddock
William Farr
Epidemiologic surveillance includes which of the following activities? (Select all that apply.)
XXXXX
A "complete causal mechanism" that inevitably produces disease is known as a what? Risk factor Sufficient cause Necessary cause Component cause
XXXXXX
According to more modern thinking about case-control studies, the purpose of the control group is to: be a comparison for disease rates. provide information on the exposure distribution in the population that produced the cases. control confounding. All of the other answers is correct.
XXXXXX
An exposure-response curve is related to which of Hill's criteria? Consistency Biological gradient Coherence Strength of association
XXXXXX
Evaluating an odds ratio describing the relationship between an exposure and outcome is an example of which of Hill's criteria? Consistency Specificity Coherence Strength of association
XXXXXX
Fluoride was added to the drinking water supply of a small town to measure the effectiveness of fluoride in reducing cavities in children. This is an example of what type(s) of experimental study? (Select all that apply.) Individual trial Community trial Preventive trial Therapeutic trial
XXXXXX
Identify the most appropriate type of cohort study (retrospective, prospective, or both) for each description. Less vulnerable to bias Poor information on exposures and other key variables Can directly measure disease incidence or risk and evaluate multiple effects of an exposure
XXXXXX
Magnitude of confounding can be estimated by which equation? (Adjusted RR - Crude RR)/Crude RR (Crude RR - Adjusted RR)/Crude RR (Crude RR - Adjusted RR)/Adjusted RR (Adjusted RR - Crude RR)/Adjusted RR
XXXXXX
Recall bias in a case-control study is introduced when: cases recall exposure differently from controls. all members of the study incorrectly recall exposures. cases outnumber controls. All of these answers are correct
XXXXXX
The analysis that answers the question: "How well does the treatment work among those who take the treatment as directed?" is known as: intent-to-treat. advocacy analysis. efficacy analysis. CAPRIE analysis.
XXXXXX
The best way to avoid selection bias from loss to follow-up in a cohort study is to:
XXXXXX
What is the major difference between a PMR study and an SMR study? PMR studies mortality while SMR studies morbidity. SMR studies mortality while PMR studies morbidity. PMR uses proportionate mortality while SMR uses mortality rates. There is no difference between the two.
XXXXXX
When the International Classification of Disease (ICD) is revised, deaths from a specific cause tend to increase decrease remain the same Cannot tell without knowing more
XXXXXX
Which new drug trial phase is conducted in a relatively small number of healthy volunteers to provide preliminary information on drug safety? Phase I Phase 2 Phase 3 Phase 4
XXXXXX
Which of the following is a negative cause of disease? Cigarette smoking Hormone replacement therapy Vitamins Ionizing radiation
XXXXXX
Which of the following study designs are considered observational studies? (Choose all that apply.) Cohort study Cross-sectional study Clinical trial Case-control study Experimental study Ecologic study
XXXXXX
Which of these is an example of an active "cause"? Vitamins Sex Geography Heritage
XXXXXX
Which technique is often used in cohort studies to translate the use of placebos to cohort studies? Random assignment Individual matching Assignment of a sham treatment
XXXXXX
Which type of study design is usually considered the most scientifically rigorous? Case-control Cohort Cross-sectional Experimental
XXXXXX
Why are "odds" calculated in a case-control study? It is the easiest measure to calculate. It is the only measure that can be calculated. It gives more information than risk or rate. It is more statistically rigorous than the risk.
XXXXXX
Why is "intent-to-treat" analysis used? (Select all that apply.) Preserves benefits of randomization Gives information about treatment under everyday conditions Helps ensure study results are unbiased Increases generalizability
XXXXXX
Suppose the true association between exposure and outcome is measured with a risk ratio of 2.0, but a biased study of this relationship results in a risk ratio of 2.5. We can say the risk ratio measured in the study is: biased away from the null. biased toward the null. an overestimate of the true association. biased away from the null and an overestimate of the true association.
biased away from the null and an overestimate of the true association.
Self-selection bias in a case-control study may occur if refusal or nonresponse is related to: case status. exposure status. case and exposure status. None of these answers are correct.
case and exposure status.
Recall bias can occur in any study design, but it is most common in: ecologic studies. case-control studies. cross-sectional studies. cohort studies.
case-control studies.
The "healthy worker effect" is a form of selection bias that occurs when: comparing a worker population to the general population. only healthy people remain in a study. only unhealthy people remain in a study. only unhealthy people are included in the study.
comparing a worker population to the general population.
One way to minimize confounding by indication is: controlling for age. controlling for the third variable. comparing treatments for the same condition. None of these answers is correct
comparing treatments for the same condition.
The type of confounding that can occur when participants are given a treatment for a specific disease that might be related to the outcome is called: confounding by severity. confounding by indication. confounding by an important variable. None of these answers is correct
confounding by indication.
The type of confounding that occurs when the severity of disease is a confounder between the treatment and outcome is called: confounding by severity. confounding by indication. confounding by an important variable. None of these answers is correct.
confounding by severity.
In a study, the mixing of effects among the exposure, outcome, and a third factor related to the exposure and outcome is called: confounding. bias. random error. None of these answers is correct.
confounding.
Trials in which all participants receive all the treatments at different times are referred to as ________. cross-over trials therapeutic trials community trials preventive trials
cross-over trials
The lifetime risk of cancer. This measure of disease frequency is cumulative incidence prevalence proportion incidence rate None of these measures
cumulative incidence Key words are "risk," which is a proportion, and "lifetime," which is a period of time
The percentage of freshman girls who become pregnant over the course of their high school years. This measure of disease frequency is cumulative incidence prevalence proportion incidence rate None of these measures
cumulative incidence The key words here are "percentage" and "become."
Cross-sectional studies evaluate associations using the population rather than the individual as the unit of study. True False
false Ecological studies evaluate associates using the population as the unit of study.
If there is a positive relationship between the exposure and disease, then the relative measure would be equal to 1.0. less than 1.0. greater than 1.0 equal to 0.
greater than 1.0
Effect measure modification is also known as: homogeneity of effect. heterogeneity of effect. absence of effect. None of these answers is correct.
heterogeneity of effect.
The number of live-born babies who die of sudden infant death syndrome during the first year of life per 100,000 baby-years of follow-up. This measure of disease frequency is
incidence rate Key words are "baby-years of follow-up" - a measure of person-time
The classic analysis for an experimental study is: logistic regression. intent to treat. regression modeling. stratification.
intent to treat.
The best comparison groups for an occupational cohort study are, in order of superiority: internal cohort, comparison cohort, and general cohort. internal cohort, general cohort, and comparison cohort. comparison cohort, general cohort, and internal cohort. general cohort, internal cohort, and comparison cohort
internal cohort, general cohort, and comparison cohort.
interviewer bias: only occurs in case-control studies. only occurs in cohort studies. may occur in all study designs. None of these answers is correct.
may occur in all study designs.
One way to study the effect of environment on health is through: case-control studies cohort studies migrant studies experimental studies
migrant studies
The most common form of bias in epidemiologic research is: selection bias. interviewer bias. recall bias. misclassification.
misclassification.
A proportional mortality ratio (PMR) study compares: exposed diseased persons to unexposed diseased persons. exposed persons to unexposed persons. mortality rates of exposed group to mortality rate of general population. mortality proportions of exposed group to mortality proportion of general population.
mortality proportions of exposed group to mortality proportion of general population.
A proportional mortality ratio (PMR) study compares: exposed diseased persons to unexposed diseased persons. exposed persons to unexposed persons. mortality rates of exposed group to mortality rate of general population. mortality proportions of exposed group to mortality proportion of general population.
mortality proportions of exposed group to mortality proportion of general population.
The detectable preclinical phase (DPCP) of a disease is a function of ________. natural history of disease and capabilities of the screening test natural history of disease and cost of the screening test capabilities of the screening test and prevalence of the disease cost of the screening test and prevalence of the disease
natural history of disease and capabilities of the screening test
Primary prevention efforts are targeted at the ___________. pathological onset stage preclinical stage remission stage relapse stage
pathological onset stage
If the True RR is 2.0 and the Adjusted RR is 3.0, confounding is said to be: positive. negative. equal.
positive
The main way to measure the feasibility of a screening program is with ________. sensitivity specificity predictive value number of people saved from disease
predictive value
The percentage of senior boys who are fathers at the time of graduation. This measure of disease frequency is cumulative incidence prevalence proportion Incidence rate None of these measures
prevalence proportion Key words are "percentage" and "are" (at a specific time).
The type of cohort study most like an experimental study is the ________ study. prospective cohort retrospective cohort ambidirectional cohort
prospective cohort
The probability that a study result is due to chance is called: confounding. bias. random error. None of these answers is correct.
random error.
Experimental studies are less likely than cohort studies to suffer from confounding by severity due to: use of two treatment groups. randomization. better retention of subjects. None of these answers is correct.
randomization.
One way to sample controls from a prospective cohort to form a nested case-control study is to sample controls throughout the period of follow-up each time a case is identified. This type of sampling is called _______. case-base sampling risk set sampling survivor sampling None of these other answers is correct.
survivor sampling
In effect measure modification, when one factor enhances the effect of another, the relationship is said to be: synergistic. antagonistic
synergistic.
The best statistical test for effect measure modification is: the chi-square test for homogeneity. the t-test. the student's t-test. None of these answers is correct
the chi-square test for homogeneity.
When survivor sampling is used for control selection in a case-control study, the odds ratio estimates ________. the odds ratio in the base population the risk ratio in the base population the rate ratio in the base population None of these answers is correct.
the odds ratio in the base population
When risk set sampling is used for control selection in a case-control study, the odds ratio estimates: the odds ratio in the base population. the risk ratio in the base population. the rate ratio in the base population. None of these answers is correct
the rate ratio in the base population.
One disadvantage of using existing records for information on exposures in a cohort study is that: it is nearly impossible to get permission to view the records. it is nearly impossible to link the exposures to the persons. the records were collected for other purposes and may not have the specific information needed for the study question. it is often difficult to interpret the records
the records were collected for other purposes and may not have the specific information needed for the study question.
When case-base sampling is used for control selection in a case-control study, the odds ratio estimates: the odds ratio in the base population. the risk ratio in the base population. the rate ratio in the base population. None of these answers.
the risk ratio in the base population.
Data from the U.S. Census are used to assign members of the House of Representatives to the state to identify denominators for incidence and prevalence measures to assign members of the House of Representatives to the states and to identify denominators for incidence and prevalence measures None of these other answers is correct.
to assign members of the House of Representatives to the states and to identify denominators for incidence and prevalence measures
Important reasons to conduct surveillance on a regular basis include: (Select all that apply.) to establish a baseline in the community to identify an outbreak in the community to monitor disease trends. to collect data for a case-control study.
to establish a baseline in the community to identify an outbreak in the community to monitor disease trends.
One reason for conducting a nested case-control study within a cohort study is: to reduce the expense of obtaining exposure data on the entire cohort to prove that case-control studies are as rigorous as cohort studies to identify a rare exposure None of the other answers is correct.
to reduce the expense of obtaining exposure data on the entire cohort
An alternative to an intent-to-treat analysis is an efficacy analysis. True False
true
An important difference between an observational study and an experimental study is that exposures are assigned to participants in experiments. True False
true
Cohort studies are also called "follow-up," "incidence," and "longitudinal" studies. True False
true
The primary disadvantage of passive surveillance is over-reporting under-reporting that it uses more public health resources than active surveillance does that it requires the use of official vehicles
under-reporting
The principle of equipoise relates to whether ______. whether participants are treated fairly whether there is genuine uncertainty about risks and benefits of a treatment whether a placebo has been introduced into the study design whether the control and test groups have equal numbers
whether there is genuine uncertainty about risks and benefits of a treatment
"Place" is an important aspect of disease distribution because it includes aspects of what? (Select all that apply.) Physical environment Biological environment Social environment Time differences
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To calculate the attributable portion (AP) among the exposed, you would use what? (Select all that apply.) The risk in the exposed The risk in the unexposed The risk in the population None of these answers is correct.
xxxxxx
An important work that helped mark the transition from the social reform era to the infectious disease era was the Bradford-Hill Criteria Poor Law Henle-Koch PostulatesMalthusian Theory
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