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PHC 6000m (T/F)

Introduction to epidemiology (T/F)

QuestionAnswer
T/F: An advantage of cohort designs compared to the pure ca/co designs is that cohort studies can directly estimate risks. True
T/F: The temporal sequence of exposure and disease can be directly addressed in a cohort design as well as in a ca/co study. False
T/F: As described in class, a randomized clinic trial is an example of a prospective dynamic cohort study. True
T/F: A disadvantage of the cohort design compared to a ca/co study is that in a cohort study one needs to follow a large number of participants if the disease is rare. True
T/F: A case report is a type of descriptive study that is commonly conducted, partially because an appropriate control group is easily defined. False
T/F: The study of person, place, and time helps to understand the natural history of a disease. False
T/F: A risk difference is determined by the absolute difference in two incidence rates, whereas the relative difference is considered an attributable risk. True
T/F: As an estimate of a relative risk, an odds ratio is a measure of association that can be used to determine the magnitude of an association between exposure and an outcome. True
T/F: An attributable risk proportion (AR%) is a measure of the impact assessing how much risk results from exposure levels. Attributable risks that adjust for the prevalence of the causal factor in a population is called a population attributable risk. True
T/F: Case control studies have several crucial advantages that relate to their efficiency for studying rare conditions and those with prolonged induction and their efficiency in examining many exposures and outcomes. False
T/F: The decision to use an incidence density measure or a cumulative incidence as a measure of the strength of association may depend on the objectives of the study. Cumulative incidence is preferred if estimating individual risk is the main objective.
T/F: A standardized mortality ratio (SMR) can be determined using indirect adjustment. Because rates from a standard population are used, SMR's from two study populations can be compared as long as the rates in the standard population are stable.
What are the two conditions under which cumulative incidence and incidence density will approximate each other?
T/F: Prevalence is not influenced by the duration of the disease or condition. False
T/F: A standardized mortality ratio is an example of a stratum specific crude rate. False
T/F: The indirect method of age standardization employs the use of rates from a standard population. True
T/F: A steady state population is one in which no new members enter after the period of recruitment ends. False
T/F: Point prevalence is an effective way to measure the burden of diseases with short duration. False
T/F: Standardized mortality ratios are useful when the number of events is small and multiple comparisons among populations are to be made. False
T/F: A disease with low incidence may have high prevalence in a population. True
T/F: Direct age standardization can be characterized as applying the same set of weights to the age-specific rates between populations to be compared. True
T/F: A case report is a type of descriptive study that is commonly conducted, partially because an appropriate control group is easily defined. False
T/F: Cumulative incidence can be calculated in a ca/co study. False
T/F: The main purpose of randomization is to ensure that the same numbers of study participants are in the exposed and un-exposed groups. False
T/F: If the observed relative measure of association in a study was 1.0, we would be correct in stating that there was no observed association between the exposure and the outcome. True
T/F: In a case control study, the selection of controls must be independent of their exposure status. True
T/F: Incidence density is a proportion where the units of time are specified. False
T/F: As an estimate of a relative risk, an odds ratio is a measure of association that can be used to determine the magnitude of an association between exposure and an outcome. True
T/F: For a given exposure that causes disease, the AR% will always be greater than (or equal to) the PAR% True
T/F: Ecological studies cannot directly assess causal inference because they measure disease and exposure in a person at the same point in time. False
T/F: In a valid study, there is neither systematic error nor random error. False
T/F: The study population is always a subset of the source population. False
T/F: The sample is always a subset of the source population. False
T/F: Suppose the risk ratio in the source population is 3.0, whereas the risk ratio in the study population is 1.2. Then the study is not internally valid. True
T/F: If the estimated RR equals 2.7 in the sample and it is determined that there is a bias away from the null, then the RR in the target (i.e., source) population is greater than 2.7. False
T/F: If the estimated RR in the sample is 1.1 and it is determined that there is a bias away from the null, then there is essentially no association in the target population. True
T/F: If there is differential misclassification of disease status but not of exposure status in a ca/co study, then there may be bias in estimating the odds ratio, which is either away from or toward the null. True
T/F: Cumulative incidence can be calculated in a case-control study False
T/F: The main purpose of randomization is to ensure that the same numbers of study participants are in the exposed and un-exposed groups False
T/F: If t he observed relative measure of association in a study was 1.0, we would be correct in stating that there was no observed association between the exposure and the outcome True
T/F: A case report is a type of descriptive study that is commonly conducted, partially because an appropriate control group is easily defined False
T/F: In a case-control study, the selection of controls must be independent of their exposure rates True
T/F: Incidence density is a proportion where the units of time are specified False
T/F: As an estimate of a relative risk, an odds ration is a measure of association that can be used to determine the magnitude of an association between exposure and an outcome True
T/F: For a given exposure that causes disease, the AR% will always be greater than (or equal to) the PAR% True
T/F: Ecological studies cannot directly assess causal inference because they measure disease and exposure in a person at the same point in time False
Created by: AlneciaPHS