Post Four: Results

Coefficient P-value
Union Membership -3.36 0.003
Mexican Border 0.467 0.197
Perot Vote 0.565 0.574
Household Income 0.033 0.076
Corporate Contributions -0.313 0.604
Labor Contributions -4.137 0.000

 

The coefficient sign for “Labor Contributions” is negative, which means a Congressman with a high proportion of contributions from labor-related political action committees will be likely to shift his attitude toward voting against NAFTA.  Since the p-value is less than .01, we can reject the null hypothesis with 99% certainty.  The null hypothesis is this case is that there is no relationship between “Labor Contributions” and the “Shift” variable.

The coefficient sign for “Union Membership” is negative, which means a Congressman with a high proportion of private-sector workers in unions will be more likely to shift his attitude toward voting against NAFTA.  Since the p-value is less than .01, we can reject the null hypothesis with 99% certainty.  The null hypothesis is this case is that there is no relationship between “Union Membership” and the “Shift” variable.

The remaining independent variables in the analysis (“Mexican Border,” “Perot Vote,” “Household Income,” and “Corporate Contributions”) do not have P-values lower than .05, so we cannot reject the null hypothesis that there is no relationship between these independent variables and the “Shift” variable.

The statistical significance of the “Labor Contributions” variable fits my hypothesis because interest groups actively influence Congressional voting, and it is likely that lobbyists working for the labor interest groups met with Congressmen and convinced them to shift their vote against NAFTA.

The statistical significance of “Union Membership” is unexpected, since constituents are not as likely as interest groups to play an active role in influencing Congressional voting.  It is possible, however, that the variables “Labor Contributions” and “Union Membership” are related.