Wednesday, May 15, 2013

Final Project for Coursera "Passion Driven Statistics"

Title - The Association Between Marital Status and Voting in the 2000 Election

Many factors are thought to have an impact on voting.  Racial, cultural and religious identity may all play a role, as well as views on economic, social, and foreign policy.  One of the factors which may be associated with voting patterns is marital status.  Since non-married people do not have a spouse to fall back on in case of a job loss, pregnancy, or disability, they may be more keenly aware of the need for government assistance and therefore more likely to vote for a larger social welfare state, and therefore for the Democratic candidate.  If this hypothesis is correct, non-married (widowed, divorce or single) people who are caring for children are even more likely to feel the need for a large welfare state, and therefore perhaps more likely to support the democratic candidate.

Research Questions
  1. For independent voters who voted in the 2000 election, are nonmarried people (single, widowed, divorced) more likely to vote for the democratic candidate?
  2. Is the association between marital status and voting similar for individuals with and without a child under 18 at home?
    Sample - The 1987 to 2012 Values Merge File contains core values questions from 15 surveys conducted between May 1987 and April 2012, some of which were done face-to-face and some over the telephone.  The combined N=35,578.
    Measures - Data for voting, marital status, and dependent at home were based on telephone or in-person responses.  We filtered out follwing: those who were not asked about whether htey had kids at home, those who did not vote for either the republican or the democrat, and those who were affiliated with either the republican or the democratic party.  In other words, we are looking only at those who voted but did not have an affiliation with either political party.  For marital status, we converted the data so that the values are either married, not married, or did not respond.

    Univariate - Independents (those not identifying as Republican or Democrat) who voted for a non-third party candidate in the 2000 election voted for the Democrat 40.26% of the time.  63.6% of the sample was married, and 31.29% reported having kids living at home.

    Bivarite - As expected, the chi-squared analysis shows that nonmarried (single, widowed, divorced) are more likely to vote for the Democratic presidential candidate - in our sample, 46.85% of married voted for the Democrat, while 58.73% of unmarried voted for the Democrat, and the chi-squared test has a p-value below .001.  When we look at those with and without kids, we see that for both married and unmarried, those with kids at home under 18 are less likely to vote for the Democrat than those without.

These results confirm the well-known pattern that non-married people are more likely to vote for the Democrat than married people.  Further, they show that those without kids at home are more likely to vote for the Democrat than those with kids at home.  However, we do not know much about the causality - are Democratic voters less likely to marry?  Or does marriage cause a change in voting patterns?  This study does not give sufficient evidence to make a determination.  Also, this study only looks at the 2000 election, so the result might not generalize to other election years.  

For future research, it would be good to look at a wider array of demographic features, to see whether marital status was the best predictor to look at, or whether a different indicator (correlated with marital status) would better predict voting patterns.  It would be also interesting to look at the same voters across time - if someone moves from single status to married or from married to divorced or widowed, does this change cause a change in voting?