All Terms Flashcards
The incidence of a disease in a population.
Absolute risk
The probability of making a type II error, i.e. the error of failing to reject a false null hypothesis.
Beta
The degree to which a measurement or an estimate based on measurements represents the true value of the attribute that is being measured.
Accuracy
The rate of outcome after controlling for a variable or variables across the entire population or both groups of comparison.
Adjusted Rates
Defined as the number of people at risk who develop a certain disease divided by the total number of people at risk.
Attack Rate
The amount or proportion of disease incidence that can be attributed to a specific exposure.
Attributable risk
Any systematic error in the design, conduct or analysis of a study that results in a mistaken estimate of an exposure’s effect on the risk of disease.
Bias
A form of selection bias that leads hospital cases and controls in a case-control study to be systematically different from one another.
Berkson’s bias
The probability of making a type I error, i.e. the error of rejecting a true null hypothesis.
Alpha
Keeping the observer(s) and/or subjects ignorant of the group to which the subjects are assigned.
Case
A distribution in which there are two peaks.
Bimodal Curce
A study in which cases are defined as those with the disease and controls are those without the disease. We can then study the significance between exposure and non-exposure from the two groups. Note: This study begins with diseased and non-diseased people.
Case-control study
An alternative to randomization in that no comparison is made with an untreated group or with a group receiving some other treatment.
Case study
Determines what percentage of people diagnosed as having a certain disease die within a certain time after diagnosis.
Case-fatality rate
Factors that increase risk for an event.
Causal Factors
A disease that will last for a considerable amount of time if not until death. Ill-effects and/or complications are usually delayed and gradual.
Chronic Disease
Disease characterized by signs and symptoms.
Clinical disease
A study that compares the incidence of disease between a group of exposed individuals and a group of non-exposed individuals. Note: This study begins with exposed and non-exposed people.
Cohort Study
Outbreak due to exposure of a group of persons to a noxious influence that is common to the individuals in the group.
common source epidemic
The computed interval with a given probability, e.g. 95%, that the true value of a variable is contained within the interval.
confidence interval
term used when variables or factors known to be related, or associated with, can influence the state of the subjects being studied.
confounding
Table of observed frequencies where the rows correspond to one variable of classification and the columns correspond to another variable of classification; simplest form is the two by two table.
contingency table
A study in which both exposure and disease outcome are determined simultaneously for each subject; it is as if we were viewing a snapshot of the population at a certain point of time.
cross-sectional study
The difference between a true value and that obtained as a result of faulty design of a study.
design bias
The process of determining health status and the factors responsible for producing it.
diagnosis
One determinant is directly associated with an outcome without any intermediate determinants.
direct cause
Transmitting an agent directly from the host to the susceptible. For example, person-to-person transmission by direct contact.
direct transmission
Study conducted during a foodborne-illness investigation where the investigators ask whether the suspect food was eaten or not eaten.
eaten/not eaten study
The change of one factor alters the outcome involved. Using a factor, i.e. age, to modify the effect of a putative causal factor under study.
effect modification
The habitual presence of a disease within a given geographic area. Also referred to as the usual occurrence of a given disease within such an area.
endemic
The incidence is calculated by using a period of time during which all of the individuals in the population are considered to be at risk for the outcome.
Cumulative incidence
The occurrence in a community or region of a group or illnesses of similar nature, clearly in excess of normal expectancy, and derived from a common or a propagated source.
Epidemic
The study of the distribution and determinants of health-related states or events in specified populations and the application of this study to control health problems.
epidemiology
All that which is external to the individual human host.
encironment
A graphic plotting for the distribution of cases by times of onset.
epidemic curve
synonymous with attributable fraction.
etiologic fraction
The cause of a disease.
etiology
The absolute difference between the rates of disease in the entire population and the rates of disease among the non-exposed.
excess risk
The ability to generalize your treatment over an entire population based on the results of your sample study population.
external validity
People who have the disease and who are erroneously called “negative”
false negatives
People who do not have the disease and who are erroneously called “positive” by the test.
false positives
Number of people who ate a certain food and became ill divided by the total number of people who ate that food.
food specific attack rate
1) Introduction 2) Methods 3) Results 4) Discussion
four parts of scientific manuscript
A cohort study on cardiovascular disease, which was begun in 1948 in Massachusetts and consisted of a little over five thousand subjects.
Framingham study
Was the first to create vital statistics table.
Graunt John
A mathematical modeling technique that allows one to analyze prospectively collected data.
hazard model
Defined as the resistance of a group to an attack by a disease to which a large proportion of the members of the group are immune.
herd immunitiy
Father of medical statistics.
AB HILL
See retrospective cohort study.
historical cohort
Constant or uniform measures or variances across strata.
homogeneity
Denotes transmission from one person to another, directly or indirectly.
horizontal transmission
A person or other living animal that affords subsistence or lodgment to an infectious agent under natural conditions.
host
A study design which is a combination of more than one standard study design.
hybrid study design
A concept used that suggests that the visible or clinical cases of disease represent a small fraction of the actual prevalence.
iceberg concept of disease
Forcing in values for missing data.
imputation
The number of new cases of a disease that occur during a specified period of time among all person-time for a population at risk for developing the disease.
incidence denisty
The number of new cases of a disease that occur during a specified period of time among all persons in a population at risk for developing the disease. It is a measure of risk.
incidence rate
The interval from receipt of infection to the time of onset of clinical illness.
incubation period
The first case in a family or other defined group to come to the attention of the investigator.
index case
One determinant is indirectly associated with an outcome usually with intermediate determinants.
Indirect Cause
Transmission of an agent from host to susceptible by means of a vector, i.e. water.
Indirect transmission
An illness due to a specific infectious agent or its toxic products that arises through transmission of that agent or its products from an infected person, animal, or reservoir to a susceptible host, either directly or indirectly through an intermediate plant or animal host, vector, or the inanimate environment
infectious disease
A flaw in measuring exposure or outcome data that results in different quality of information between comparison groups.
information bias
Voluntary consent given by a subject for participation in a study after being informed of the purpose and risks.
informed consent
Interaction occurs when the incidence rate of disease in the presence of two or more risk factors differ from the incidence rate expected to result from their individual effects.
interaction
Systematic error due to interviewers’ subconscious or conscious gathering of selective data.
interviewer vias
Pioneered studies in vaccination. He was interested in predisposing people to cowpox as a means of controlling smallpox.
edward jenner
A measure of the degree of nonrandom agreement between observers of the same categorical variable.
kappa statistic
A list of postulates that should be met before a causative relationship can be accepted between a disease agent and the disease in question.
kochs postulates
An infection with no active multiplication of the agent , as when viral nucleic acid is incorporated into the nucleus of a cell as a provirus. Only the genetic message is present in the host, not the viable organism.
latent disease
Overestimation of survival time, due to the backward shift in the starting point for measuring survival that arises when diseases such as cancer are detected early, as by screening procedures.
lead time bias
A systematic error due to selection of disproportionate numbers of long-duration cases in one group but not in another.
length bias
A summarizing technique used to describe the pattern of mortality and survival in populations.
life table
Conducted one of the first randomized trials on scurvy by administering lemons randomly to the crew of a ship during the 18th century.
James Lind