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# PHC 6000m (T/F)

### Introduction to epidemiology (T/F)

Question | Answer |
---|---|

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