PSY 230 Lecture Notes - Lecture 11: Measuring Instrument, Type I And Type Ii Errors, Internal Validity
Document Summary
One-group, pretest/posttest design: an experiment in which a researcher recruits one group of participants, measures them on a pretest; exposes them to a treatment, intervention, or change, and then measures them on a posttest. Maturation threat: a threat to internal validity that occurs when an observed change in an experimental group could have emerged more or less spontaneously over time. Attrition threat: in a repeated-measures design or quasi-experiment, a threat to internal validity that occurs when a systematic type of participant drops out of the study before it ends. Testing threat: in a repeated-measures experiment or quasi-experiment, a kind of order effect in which scores change over time just because participants have taken the test more than once; include practice effects and fatigue effects. Instrumentation threat: a threat to internal validity that occurs when a measuring instrument changes over time from having been used before.
