Warning: package 'brms' was built under R version 4.4.1Warning: package 'Rcpp' was built under R version 4.4.1Warning: package 'tidybayes' was built under R version 4.4.1Warning: package 'gtsummary' was built under R version 4.4.1N Parameters
Using the results of a voting experiment in Michigan in 2006, we seek to forecast the causal effect on voter participation of sending postcards in the Texas general election for governor of 2026. There is concern that data from a primary election might not generalize to a general election and that political culture in the two states (Michigan and Texas) differ too much to allow for data from one to enable useful forecasts in the other. We modeled primary_06, a binary 0/1 integer variable indicating whether the respondent voted in the 2006 primary election, and the type of postcard they received. People who have been voting in the past are more likely to vote again. The best combination of Voter Class and Postcard Type is the Neighbors postcard and people who have a tendency to vote. This is our best guess. It is an informed estimate based on the most relevant data possible. From that data, we have created a 95% confidence interval for the treatment effect of various postcards: between 8% to 10%.
\[y_{i} = \beta_{0} + \beta_{1} age\_z + \beta_{2}male_i + \beta_{3}civic\_duty_i + \\ \beta_{4}hawthorne_i + \beta_{5}self_i + \beta_{6}neighbors_i + \\ \beta_{7}Sometimes\ vote_i + \beta_{8}Always\ vote_i + \\ \beta_{9}civic\_duty_i Sometimes\ vote_i + \beta_{10}hawthorne_i Sometimes\ vote_i + \\ \beta_{11}self_i Sometimes\ vote_i + \beta_{11}neighbors_i Sometimes\ vote_i + \\ \beta_{12}civic\_duty_i Always\ vote_i + \beta_{13}hawthorne_i Always\ vote_i + \\ \beta_{14}self_i Always\ vote_i + \beta_{15}neighbors_i Always\ vote_i + \epsilon_{i}\]
Warning in tidy.brmsfit(x, ..., effects = "fixed"): some parameter names
contain underscores: term naming may be unreliable!Characteristic |
Beta |
95% CI 1 |
|---|---|---|
| (Intercept) | 0.155 | 0.137, 0.174 |
| age_z | 0.036 | 0.031, 0.042 |
| sex | ||
| sexMale | 0.004 | -0.005, 0.014 |
| treatment | ||
| No Postcard | — | — |
| treatmentCivicDuty | 0.016 | -0.027, 0.057 |
| Hawthorne | 0.004 | -0.037, 0.043 |
| Self | -0.007 | -0.049, 0.035 |
| Neighbors | 0.084 | 0.041, 0.126 |
| voter_class | ||
| Rarely Vote | — | — |
| voter_classSometimesVote | 0.115 | 0.095, 0.135 |
| voter_classAlwaysVote | 0.298 | 0.275, 0.321 |
| treatment * voter_class | ||
| treatmentCivicDuty * voter_classSometimesVote | -0.005 | -0.051, 0.043 |
| Hawthorne * voter_classSometimesVote | 0.010 | -0.033, 0.054 |
| Self * voter_classSometimesVote | 0.059 | 0.012, 0.106 |
| Neighbors * voter_classSometimesVote | -0.009 | -0.057, 0.038 |
| treatmentCivicDuty * voter_classAlwaysVote | -0.009 | -0.061, 0.045 |
| Hawthorne * voter_classAlwaysVote | 0.034 | -0.017, 0.086 |
| Self * voter_classAlwaysVote | 0.047 | -0.007, 0.100 |
| Neighbors * voter_classAlwaysVote | -0.002 | -0.056, 0.050 |
| 1
CI = Credible Interval |
||