Question

Using MR SMITH and his ID, identify two potential internal validity threats that might affect the A—B design. Tell me how that threat might impact conclusions in the A—B design. Note #1: You cannot use maturation (since I already did that one for you!). Note #2: There are some MR SMITH ID threats that won’t have much impact in a single case design.

Answer 1

1. History: Events that occur besides the treatment (events in the environment) may infact be responsible for the change observed across the conditions. The researchers should obtain as much information as possible about Mr. Smith and keep the time gap between the pretest and posttest as short as possible.

2. Repeated testing: Repeatedly measuring Mr. Smith may lead them to remember the certain response patterns and alter their behaviour due to practice or fatigue. To encounter this issue, researchers can use alternative or parallel forms of the measurement tool.