Explain and give examples of how the particular outcomes of

Explain and give examples of how the particular outcomes of a study can suggest if a particular threat is likely to have been present.

Solution

When randomization is not used, such as with a quasi-experiment, the study is at a higher risk of confounds (threats). This is one of the main threats to the internal validity of a study. Quasi-experimental designs are considered to be weak designs, and thus the conclusions of these studies need to be interpreted carefully. Possible confounds may include a history effect, maturation effect, testing effect, diffusion of treatment, regression to the mean, experimental mortality, selection-maturation interaction, John Henry effect. Much efforts to avoid/reduce the threats against internal valdity and external validity. However, some widespread concepts may also contribute other types of threats against internal and external validity.