Exercise 9: Candidate character and presidential vote
Another reason for using three-variable tables in our data analysis is to examine the joint influence of two independent variables on a dependent variable. To illustrate this situation, we can consider the influence of how perceptions of candidate personal characteristics influence the vote. Specifically, we can look at how voters perceived the leadership abilities of Obama and McCain1.
To begin, you should generate frequency tables that show how voters perceived the leadership abilities of the two candidates (V028 and V034).
The next question is whether these perceptions of leadership ability are related to the vote. You should generate a table that shows how perceptions of Obama's leadership ability (V028) were related to the vote. For the reasons suggested in exercise one, you should use the recoded version of V002 that you created for that exercise, so that you examine only the major-party vote (i.e., only the Obama and McCain voters). After creating this table (Table 9C), create a similar table (9D) using the same question about McCain's leadership abilities (V034).
Tables 9C and 9D each indicate that perceptions of both Obama's and McCain's leadership abilities were related to the vote. However, looking at each perception separately does not answer the most interesting question, which is what effect perceptions of differences between the candidates have on the vote. That is, some voters who thought that Obama was a strong leader may also have felt the same about McCain, in which case they did not see a difference between the candidates on this attribute. Other voters who thought that Obama was a strong leader may have felt that McCain was not, and this group clearly saw a difference between the candidates on this attribute. To examine the joint influence of V028 and V034 on the presidential vote, you should generate a three-variable table. In this case, it does not matter whether V028 is treated as the independent variable and V034 as the control variable or the reverse. In order to simplify the table, first recode V028 and V0342 so that are dichotomized into simply favorable and unfavorable responses.
1This dataset contains several items of information about the perceptions of the personal characteristics of the two presidential candidates, including questions that asked the respondents whether or not they thought that Obama and McCain were strong leaders (V028 and V034). These items asked respondents whether the phrase "he would provide strong leadership" characterized each candidate extremely well, quite well, not too well, or not well at all. These questions were only asked of one-half of the sample.
2Recoding V028 and V034: Tables 9C and 9D show that the greatest difference in voting is between those with a favorable view of the candidate and those with an unfavorable view. In each table, the difference between the "extremely well" column and the "quite well" column is not nearly as great as the difference between the "quite well" and "not very well" columns. The "not very well" and "not at all" columns also are not that different. Therefore, it is reasonable to dichotomize these variables into those with a favorable view and those with an unfavorable view. This will simplify our three-variable table and will increase the Ns in the columns. Since these questions were only asked of one-half of the sample, this second consideration is important.