Chong-ho Yu (2021) Show
The books by Campbell and Stanley (1963), Cook and Campbell (1979), and Shadish, Cook, and Campbell, (2002) are considered seminal works in the field of experimental design. The following write-up is based upon their books with insertion of my examples and updated information. Problem and Background
Factors Jeopardizing Internal and External ValidityPlease note that validity discussed here is in the context of experimental design, not in the context of measurement. Three Experimental DesignsTo make things easier, the following will act as representations within particular designs: Three True Experimental DesignsThe next three designs discussed are the most strongly recommended designs: Discussion on causal inference and generalizationAs illustrated above, Cook and Campbell devoted much efforts to avoid/reduce the threats against internal validity (cause and effect) and external validity (generalization). However, some widespread concepts may also contribute other types of threats against internal and external validity. Reference
Go up to the main menu Which of the following is a threat to internal validity in a pretestAnother threat to the internal validity of one-group pretest-posttest designs is testing , which refers to when the act of measuring the dependent variable during the pretest affects participants' responses at posttest.
What is a major problem with the pretestThe main problem with this design is that it improves internal validity but sacrifices external validity to do so. There is no way of judging whether the process of pre-testing actually influenced the results because there is no baseline measurement against groups that remained completely untreated.
Which threat to internal validity is of particular concern to pre post designs?An example of a threat to internal validity would be selection bias.
What is the main threat to the internal validity of a oneAnother threat to the internal validity of one-group pretest-posttest designs is testing which refers to when the act of measuring the dependent variable during the pretest affects participants' responses at posttest.
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