Exercise 3. Attitude on Social Security Spending and the Presidential Vote.
Studies of voting behavior often attempt to explain voting behavior on the basis of certain policy issues. The hypothesis is that voters choose between candidates based on their issue positions. One public policy issue that has received attention in recent years concerns federal entitlement programs, such as Social Security or Medicare. Democrats have long been viewed as more supportive of these programs, and Obama and Romney differed on this issue. It seems reasonable to hypothesize that voters who wanted more spending on Social Security would have been more likely to vote for Obama than would voters who did not favor increasing spending on Social Security. To examine this possibility, we can look at a table that relates attitude on Social Security spending (J23) to the presidential vote. For the reasons suggested in Exercise 1, you should use the recoded version of A02 that you created for that exercise, so that you examine only the major-party vote (i.e., only the Obama and Romney voters).
After examining Table 3A, you should conclude that those who favored increasing Social Security spending had a greater propensity to vote for Obama than did those who who wanted to hold spending constant or reduce it. Does this prove that voters cast their ballots in part on the basis of this issue, or is there something else that might cause this relationship? In social science research, we have to be careful about attributing causality. Often, two variables are associated not because one affects the other but because both are influenced by a confounding variable.
One possible confounding variable is party identification. The relationship in Table 3A could be due to both variables being affected by party identification. To examine this possibility, you need to construct a three-variable table that shows the relationship between attitude on Social Security spending, presidential vote, and party identification. To keep the table simple and to have a sufficient N for each column, you should recode J23 so that it has just three categories (more spending, same spending, and less spending) and use the recoded version of party identification that you created for Exercise 1 (Democrats, independents, and Republicans).
In this example, the relationship between attitude toward Social Security spending and presidential vote is extremely weak once we control for party identification. This tells us that the original relationship between the attitude and the vote is basically spurious.