NR503 Epidemiology Actual
Midterm& Final Exam latest Exam
2025 Latest
prospective studies
begins with a defined population and then follows a group of people who were exposed
or not exposed to compare incidence of outcome
scientific misconduct
fraud. includes gift authorship, data fabrication, plagiarism, conflict of interest
random error
Measurements are either too high or too low in equal amounts because of random
factor. Less serious than bias because they generally don't distort findings
confounding error
occurs when it appears that a true association exists between an exposure and an
outcome but in reality, the association is from another variable or exposure. a
situation in which an exposure and an outcome is distorted by the presence of another
variable.
retrospective studies
exposure is ascertained from past records and outcomes are ascertained as the study
begins
bias/systematic error
broken down into two categories: selection and information
,selection bias
occurs when selected subjects in a sample are not representative of the population of
interest or comparison group
withdrawal bias
can occur when people of certain characteristics drop out of a group at a different rate
than they do in another group or are lost to follow-up at a different rate
volunteer bias
people who volunteer to participate in a study may have characteristics that are
different from people who do not volunteer impacting outcome of results
information bias
bias in how information and data are collected
exclusion information bias
can occur when one applies different eligibility criteria to the cases and control groups
measurement bias
occurs during data collection possible caused by an error in collecting info for an
exposure or outcome.
misclassification differential bias
, occurs when a case is misclassified into exposure groups more often than controls
misclassification bias
a control may be recorded as a case or a case is classified as having an exposure
incorrectly
contamination bias
occurs when members of a control group are exposed to an intervention
reporting bias
occurs when a subject may not report a certain exposure as he or she may be
embarrassed or not want to disclose personal information
recall bias
happens when subjects are asked to remember or recall events from the past
publication bias
refers to the tendency of peer-reviewed journals to publish a higher percentage of
studies with significant results rather than those studies with nonsignificant or
negative statistical results
randomized control trial
assigns patients randomly to either receive new treatment/intervention or not to.
Inclusion criteria must be precise and spelled out
strengths: lower chance or confounding variables, minimize bias in treatment
assignments, able to control intervention/treatment
Midterm& Final Exam latest Exam
2025 Latest
prospective studies
begins with a defined population and then follows a group of people who were exposed
or not exposed to compare incidence of outcome
scientific misconduct
fraud. includes gift authorship, data fabrication, plagiarism, conflict of interest
random error
Measurements are either too high or too low in equal amounts because of random
factor. Less serious than bias because they generally don't distort findings
confounding error
occurs when it appears that a true association exists between an exposure and an
outcome but in reality, the association is from another variable or exposure. a
situation in which an exposure and an outcome is distorted by the presence of another
variable.
retrospective studies
exposure is ascertained from past records and outcomes are ascertained as the study
begins
bias/systematic error
broken down into two categories: selection and information
,selection bias
occurs when selected subjects in a sample are not representative of the population of
interest or comparison group
withdrawal bias
can occur when people of certain characteristics drop out of a group at a different rate
than they do in another group or are lost to follow-up at a different rate
volunteer bias
people who volunteer to participate in a study may have characteristics that are
different from people who do not volunteer impacting outcome of results
information bias
bias in how information and data are collected
exclusion information bias
can occur when one applies different eligibility criteria to the cases and control groups
measurement bias
occurs during data collection possible caused by an error in collecting info for an
exposure or outcome.
misclassification differential bias
, occurs when a case is misclassified into exposure groups more often than controls
misclassification bias
a control may be recorded as a case or a case is classified as having an exposure
incorrectly
contamination bias
occurs when members of a control group are exposed to an intervention
reporting bias
occurs when a subject may not report a certain exposure as he or she may be
embarrassed or not want to disclose personal information
recall bias
happens when subjects are asked to remember or recall events from the past
publication bias
refers to the tendency of peer-reviewed journals to publish a higher percentage of
studies with significant results rather than those studies with nonsignificant or
negative statistical results
randomized control trial
assigns patients randomly to either receive new treatment/intervention or not to.
Inclusion criteria must be precise and spelled out
strengths: lower chance or confounding variables, minimize bias in treatment
assignments, able to control intervention/treatment
