Study Designs in Epidemiology

-a specific plan or protocol for  conducting a research study, which allows the  investigator to translate the conceptual hypothesis  into and operational one

-refers to how accurately a study answers the study question or the strength of the study conclusions

-The degree to which any statements of effects are actually the result of  the exposure of interest and not from some other interfering variable

-The extent to which the conclusions from a given study can be extended,  or generalized, beyond the current sample and target population to the  general population

-refers to whether an assessment instrument gives the same results each time it is used in the same setting with the same type of subjects

_________ is a measure of accuracy while ________ is a measure of consistency.

What are some common threats to internal validity?

–Typically describe an unusual case (maybe even a surprising recovery or unintended  beneficial effect), including the presentation of the case, the course of action taken by the  author (usually practitioners), and sometimes conjectures as to possible causal  explanations

-Similar to a case report except the description is of clinical findings seen in a succession of  patients who seem to share common clinical characteristics, rather than a single case  report

-All the information collected refers to the same point in time. These studies are  snapshots of the population status with  respect to disease or exposure variables, or  both, at a specific point in time

-Observational studies that enroll one group of  persons with a certain disease, chronic condition,  type of injury, or any outcome of interest (case-  patients) and a group of persons without the outcome of interest (control subjects) and compares differences in exposures, behaviors, and  other characteristics to identify and quantify  associations, test hypotheses, and identify causes

Which study design is particularly useful when the outcome of interest is relatively rare?

a) cross-sectional

b) case-control

c) case-series

d) cohort

-Observational studies in which enrollment is based on status of exposure to a certain factor or membership in a certain group. Populations are followed, and disease, death, or other health-related outcomes are documented and  compared

Which study design is as an observation and comparison of disease experience among exposed and unexposed groups?

a) cross-sectional

b) case-control

c) case-series

d) cohort

-this type of study design looks at associations from a group level rather than individuals; aggregate-level data

-a case-control design within a cohort

-used as a less expensive option to study various outcomes in a cohort than making measurements on everyone.

-compares exposure status during the time period immediately before an outcome with the exposure status in a time period where an outcome did not occur

-process to comprehensively identify all studies for a specific focused question, appraise the methods of the studies, summarize the results, present key findings, identify reasons for different results across studies, and cite  limitations of current knowledge

-when results of a systematic review are mathematically combined (a process sometimes referred to as pooling)

-content expert writes about a particular field, condition, or treatment – focus is broad (this is traditionally how review articles were written)

What are the disadvantages when it comes to case series & case reports?