Chapter 7

• Concurrent validity


  The degree to which scores on the measuring instrument correlate with another known standard for measuring the variable being studied.
• Confounding

  • An error that occurs when the value of an extraneous variable changes systematically along with the independent variable in an experiment
  • An alternative explanation for the findings that threatens internal validity.
• Construct validity


  The degree to which an operational definition accurately represents the construct it is intended to manipulate or measure.
• Content validity


  The degree to which the content of a measure reflects the content of what is being measured.
• Dependent variable (DV)

  • The specific behavior that a researcher tries to explain in an experiment.
  • The variable that is measured.
• Experimental operational definition

  • The explanation of the meaning of independent variables.
  • Defines exactly what was done to create the various treatment conditions of the experiment.
• Extraneous variable

  • A variable other than an independent or dependent variable.
  • A variable that is not the focus of an experiment but can produce effects on the dependent variable if not controlled.
• Face validity


  The degree to which a manipulation or measurement technique is self-evident.
• History threat


  A threat to internal validity in which an outside event or occurrence might have produced effects on the dependent variable.
• Hypothetical construct

  • Concepts used to explain unseen processes, such as hunger, intelligence, or learning.
  • Postulated to explain observable behavior.
• Independent variable (IV)


  The variable (antecedent condition) that the experimenter intentionally manipulates.
• Instrumentation threat


  A threat to internal validity produced by changes in the measuring instrument itself.
• Interitem reliability


  The degree to which different items measuring the same variable attain consistent results.
• Internal validity


  The certainty that the changes in behavior observed across treatment conditions in the experiment were actually caused by the independent variable.
• Interrater reliability


  The degree of agreement among different observers or raters.
• Level of measurement


  The type of scale of measurement—either ratio, interval, ordinal, or nominal—used to measure a variable.
• Levels of the independent variable


  The two or more values of the independent variable manipulated by the experimenter.
• Manipulation check


  An assessment to determine whether the independent variable was manipulated successfully.
• Maturation threat 


  A threat to internal validity produced by internal (physical or psychological) changes in subjects
• Measured operational definition


  The description of exactly how a variable in an experiment is measured.
• Method

  • The section of a research report in which the subjects and experiment are described in enough detail that the experiment may be replicated by others.
  • It is typically divided into subsections, such as Participants, Apparatus or Materials, and Procedures.
• Operational definition

  • The specification of the precise meaning of a variable within an experiment.
  • Defines a variable in terms of observable operations, procedures, and measurements.
• Predictive validity


  The degree to which a measuring instrument yields information allowing prediction of actual behavior or performance.
• Reliability


  The consistency and dependability of experimental procedures and measurements.
• Selection interactions

  • A family of threats to internal validity produced when a selection threat combines with one or more of the other threats to internal validity.
  • When a selection threat is already present, other threats can affect some experimental groups but not others.
• Selection threat


  A threat to internal validity that can occur when nonrandom procedures are used to assign subjects to conditions or when random assignment fails to balance out differences among subjects across the different conditions of the experiment.
• Statistical regression threat

  • A threat to internal validity that can occur when subjects are assigned to conditions on the basis of extreme scores on a test.
  • Upon retest, the scores of extreme scorers tend to regress toward the mean even without any treatment.
• Subject mortality threat


  A threat to internal validity produced by differences in dropout rates across the conditions of the experiment.
• Testing threat


  A threat to internal validity produced by a previous administration of the same test or other measure.
• Test-retest reliability


  Consistency between an individual’s scores on the same test taken at two or more different times.
• Validity

  • The soundness of an operational definition.
  • In experiments, the principle of actually studying the variables intended to be manipulated or measured.