Question:At Committee Meetings, there is a single question that requires members to make a recommendation or decision.
This week, use the internal validity handout to make decisions about the following two research scenarios. First, decide if the study is internally valid. If is not valid, decide which internal validity threat applies to the situation. In both cases, provide a strong rationale for your decision.
a. Yes.This experiment is internally valid.
No. This experiment is not internally valid, and the source of threat is:
e. Repeated Testing
g. Regression to the Mean
h. Experimental Mortality
i. Selection-Maturation Interaction
j. Experimenter Bias
Scenario 1: Mrs. Smith’s husband suffered a stroke, one result being that he very rarely spoke. Mrs. Smith consulted a behavior therapist and together they designed a reinforcement program. First, for one week, she was to act normally and place a tick mark in a specified column on a data sheet every time her husband spontaneously vocalized to her (Baseline). The next week she was to continue to keep count, but she was also to touch, praise, and smile at her husband following each of his spontaneous vocalizations (Treatment). At the beginning of the program, she sometimes got confused and placed a tick mark in the wrong column, but eventually she got it right. To see the data, click here. We can conclude that the reinforcement program was responsible for improving Mr. Smith’s spontaneous vocalizations.
Scenario 2: Behavioral researchers attempted to use their skills to combat the problem of impaired driving. For one month, on Saturday nights they measured the blood alcohol content (BAC) of departing patrons at each of two taverns (Baseline). The patrons were compensated for agreeing to do this with lottery tickets. Then, they implemented a treatment package, which included (1) placing cards on tables in the taverns instructing patrons how to pace their drinking to stay under the legal limit, (2) providing individual feedback on BAC to departing patrons, and (3) posting a large poster in each tavern indicating the percentage of patrons who drove home intoxicated the previous week. Data continued to be recorded for one more month on Wednesday nights (Treatment). To see the results, click here. We can conclude that the treatment package reduced the mean BAC of departing patrons at each of the two taverns.
*Please label your answers with a 1) for scenario one and 2) for scenario 2. List the letter that corresponds with your answer and then provide a strong rationale for your decision.
If you would like more practice with internal validity threats, click here: