EPH

Bias

Systematic errors that disproportionately affect data in one direction or another.

Random error

Error that results from measurement imperfections in a data collection system.

Inherent variability

Natural differences that exist between individuals in a population.

Internal validity

The methodological design of a study, including variables, controls, and samples.

External validity

The generalizability of a study, or how well results can be extrapolated to a larger population.

Selection bias

A form of bias that results when the sample taken is not representative of the population.

Misclassification bias

The incorrect measurement of participants or their categorization into wrong groups.

Non-differential misclassification

Equal misclassification of exposed and disease classification between subjects.

Differential misclassification

Unequal distribution of exposed and disease classification between subjects, detrimental to internal validity.

Implicit bias

Subconscious biases that affect judgments and decisions.

Explicit bias

Conscious biases that are held by an individual.

Sample size

The number of participants included in a study; smaller sizes mean a higher error percentage, while larger ones are more reflective of entire population

Convenience sampling

A non-random sampling method that often leads to biases.

Volunteer/self-selection bias

A bias that arises when participants self-select to respond or participate in a study.