External Validity

In order to gather participants for the study, I will offer $15 for completing the estimated 1 hour experiment. I will advertise the study in the local newspaper, through emails and phone calls, on college campuses, and in general public areas such as restaurants and shopping malls. Ideally I will be able to get at least 150 participants of all races, ages, party affiliation, occupations, etc. This will help to strengthen the experiments external validity and generalizability. The participants will be randomly assigned to one of the 2 treatment conditions: they will either watch “America” or “We Can Be.” The ads will be included in a commercial break about half way through a 30 minute recording of the news. Just as Shanto Iyengar and Donald

All of the experiments will be conducted in the exact same way to hold things as constant as possible. In chapter 2 of News That Matters, Iyengar and Kinder describe several ways in which external validity can be strengthened and weakened. As they describe, there is the chance that the results of my experiment would disappear in another experiment if the conditions or questions I asked were altered (13). My study is only measuring the effects of two Sanders ads on participants, but it is possible that the results would not hold for the ads of other election campaigns or candidates. This was a strength of the experiments run by Ansolabehere, who replicated his experiment with other issues, campaigns, and primary and general elections (22). To strengthen my results to this study, I would need to repeat my experiment in the same way Ansolabehere did. Another potential weakness of my experiment that Iyengar and Kinder describe is the risk that participants alter their normal behavior or become more attentive simply because they know they are taking part in a study. I attempted to reduce this through creating a more natural living room environment for the experiment and attempting to mask the study’s true motive, but there is always the possibility that these precautions will not prevent the altered