It is also possible that voters could change their attitudes after having completed the questionnaire. This could affect the validity of the results for the experimental group. To handle this eventuality, several questionnaires can be delivered over time for the whole group before the experimental group is selected. A mean can then be determined to most accurately divide the group into a similar experimental and control group.

After the experimental group is determined, negative advertisements can be displayed. In order increase the validity of this experiment, a number of survey questionnaires over time can also be delivered in order to minimize non-visible influences such as an extreme reaction to a particular person in a particular advertisement. At the same time, the same number of questionnaires can be delivered to the control group.

A mean of all the questionnaires over the determined time can then provide relatively...

This limitation can be minimized by ensuring the selected voters of their anonymity. No names or political affiliations should be required on the questionnaires, with participants known only by their participation in the experimental or control groups.
The results of such research are important in terms of determining political campaigns for the future. If voter turnout is indeed lower because of the negative advertising, politicians should therefore engage in different tactics to encourage voter turnout. On the other hand, it is also important to engage in several research studies for each question, as unknown factors could determine voter opinion and turnout.