PSY 2174 Lecture Notes - Lecture 6: Repeated Measures Design, Measuring Instrument, Quasi
12 Oct 2016
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Topic #6: lecture notes for wednesday, october 12, 2016. Step two: look at the list of threats. Step three: ask yourself is these threats are plausible to this particular design in regards to particular context. Step four: are there any other threats to internal validity. Designs used when random assignment is not possible. Quasi (aka pre-experimental) design without a comparison group. Be careful to not confuse this with repeated measures design. Example: cbt treatment in a mental health clinic. Possibly they improved over time regardless of treatment (maturation) Changes that might have happened and coincided with the treatment (history) Knowledge of getting a therapy that is supposed to work (placebo)--want to please the researcher (pretest effect--sensitization) Interpret the questions differently for the second time--means that the tool is not reliable, or instrument fluctuates naturally (instrument change) Pretest effects: repeated testing (likely to be problem if it"s a performance measureis this performance measure. Sensitization: interaction between the pre-test and the treatment.
