Biostat ch 2 definitions Flashcards
Observational Study Design
can be used to alert the medical/public health community to emerging health issues, generate/test hypotheses, and asses specific associations
Experimental Study Design
test hypotheses, evaluate the effect of the intervention, determine causality
Cohort
share common characteristics and are followed over time
Confounding Variable
distorts the relationship between the risk factors and the outcome
Cross-Sectional
at a single point in time
Incidence
number of new cases over a period of time
Prevalence
proportion of individuals with the condition (new and existing) at a single point in time
Prospective
data collected going forward in time
Retrospective
data collection looking back in time
Case Report
detailed report of specific features of case
Case Series
report on common features of a small number of cases
Case Series Example
Gottleib studied 5 young homosexual men with rare form of pneumonia and other unusual infections. Start of AIDS research
Cross-Sectional Study
conducted at a single point in time, data collected through surveys, non-randomized, estimates prevalence of risk factors, diseases, practices, or opinions, can make comparisons between groups
Cross-Sectional Study Example
Is there an association between diabetes and cardiovascular disease?
Case-Control Study
participants identified and included in study based on the presence or absence of outcome of interest, cases have disease, controls are free of disease, compare cases and controls with respect to the proportions exposed, is there a statistically significant difference bt cases and controls with regards to exposure status?
Case-Control Study Example
is there an association between sleep position and SIDS?
Cohort Study
includes persons exposed and not exposed to risk factor at outset- usually persons are disease free, follow prospectively or retrospectively, can asses temporal relationship and calculate incidence, problem if disease is rare, bias is less of an issue than case-control
Cohort Study Example
is there an increase in the incidence of CVD among those who have hypertension?
Blinding
participant is unaware of their treatment status
Double Blind
participant and outcome assessor are unaware of treatment status
Intention-to-Treat
analytic strategy whereby participants are analyzed in the treatment group they were assigned regardless of whether they followed the study procedures completly
Per protocol
analytic strategy whereby only participants adhered to the study protocol are analyzed
Placebo
inert substance designed to look, feel, and taste like the active or experimental treatment
Stratification
a process whereby participants are partitioned or separated into mutually exclusive or non-overlapping groups
Prognostic Factor
a characteristic that is strongly associated with an outcome such that it could be used to reasonably predict whether a person is likely to develop a disease or not
Efficacy
how the intervention performs under ideal conditions
Effectiveness
how the intervention performs in the real world
Randomized Control Trial
experimental study where patients are randomized to receive one of several comparison treatments
Randomized Control Trial Example
is the new drug efficacious in reducing hyperlipidemia?
