Chap 4

Front 1

deterministic causation

Back 1

The ordinary concept of causality that presumes that an effect always follows a cause; differs from the scientific concept of probabilistic causation conceptualizing effects in terms of their statistical probability.

Front 2

direct testing effect

Back 2

Occurs when the first of two observations affects the second. Same as main testing effect.

Front 3

experiment

Back 3

A rigorous investigation in which the researcher controls several (independent) variables and measures or observes their effects on one or more dependent variables.

Front 4

experimental design

Back 4

A form of investigation in which the researcher can directly control one or more (independent) variables to study their effects on other (dependent) variables.

Front 5

external validity

Back 5

A method of evaluating the results of experiments; formally, the degree to which conclusions would hold under other, presumably identical circumstances (e.g., for other respondents, places, and times).

Front 6

extraneous variable

Back 6

Any variable, other than those specific to the treatment administered to test units, that may affect the response of the test units to the treatments, including the history effect, maturation effect, testing effect, instrumentation effect, statistical regression effect, selection bias, and test unit mortality; also referred to as a confound.

Front 7

history effect

Back 7

The occurrence of events outside of, but taking place at the same time as, the experiment that can affect the dependent variable.

Front 8

instrumentation effect

Back 8

In statistical models, an effect that arises when instruments, observers, or scorers change over the course of an experiment.

Front 9

internal validity

Back 9

A way to evaluate experiments by verifying that changes in the dependent or criterion variable truly arose from changes in the independent or treatment variables alone.

Front 10

maturation effect

Back 10

An effect similar to the history effect except that it pertains to changes in the experimental units themselves over time (e.g., getting older, developing fatigue, gaining experience, or learning).

Front 11

test unit mortality

Back 11

A serious problem that occurs when test units withdraw from an experiment before their role is completed.

Front 12

test units

Back 12

In experimental design, the entities to whom (or to which) treatments are presented and whose response to the treatments is measured; in practice, these are typically people, products, or firms.

Front 13

testing effect

Back 13

An effect that can come about when the pre-test itself exerts an influence on how participants perform on the post-test (e.g., when both are tests of the same skill and participants learn from the pre-test).

Front 14

treatment

Back 14

In experimental design, the manipulated independent variable whose effects are then measured.

Front 15

X-O-R syntax

Back 15

A special shorthand used to convey experimental designs: X represents the exposure of a test group to an experimental treatment, O refers to processes of observation or measurement of the dependent variable on the test units, and R indicates that individuals have been assigned at random to separate treatment groups or that groups themselves have been allocated at random to separate treatments