Methodology Definitions
Methodology Definitions

true experiment
a design in which participants are assigned randomly to treatments

a design that resembles that of an experiment in that discrete groups are used, but participants are not randomly assigned to treatments nor are treatments randomly determined for the groups.

construct variable
a theoretical variable that has 'reality status' such as competition, attractiveness, negative mood.

operational variable
the researchers' precise operational definition (i.e., measurement) of a theoretical construct.

independent variable
the variable presumed to cause a change in the dependent variable.

dependent variable
the variable presumed to be affected by the independent variable.

matching variable
an objective, quantifiable measure to help assure pretreatment equivalence among groups.

confounding variable
a variable that systematically varies along with the independent variable

a statement positing a relation between constructs

a statement of a proposed relation among two or more constructs

construct validity
the degree to which the operational definition accurately measures the construct of interest

internal validity
the extent to which causal conclusions can be drawn (i.e., the IV effects the DV)

external validity
the extent to which the results generalize to the population of interest

face validity
the extent to which measures seem to reflect the construct of interest

convergent validity
overlap among variables presumed to measure the same construct

discriminant validity
failure to find overlap among variables presumed to measure the same construct

subject variables
nonmanipulated qualities of the participant sometitmes treated as if they are true independent variables (which are manipulated and therefore their causal nature can be assessed)

random assignment
the process by which subjects receive an equal chance of being assigned to a particular condition

manipulation check
a measured variable designed to assess whether the manipulation worked and tapped the desired construct

demand characteristic
aspect of the experiment encouraging the participant to respond according to situational constraints

subject expectancies
a demand characteristic whereby subjects think they know experimenters' interests and act accordingly.

the extent to which a construct is measured without error

a procedure in which neither experimenter nor participant knows to which condition the participant are assigned

order effects
the effects on behavior of presenting two or more treatments to the same participants

a technique for controlling order effects by which each condition is presented first to each participant an equal number of times, and each condition occurs an equal number of times at each session.

control group
condition which received a zero level of the construct of interest

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