Final answer:
The most reliable factor predicting voter participation is socioeconomic status, with higher education and income levels significantly increasing the likelihood of voting.
Step-by-step explanation:
The single most reliable factor predicting voter participation is socioeconomic status, particularly the combination of education, income, and social status. Research has shown that higher levels of education and income are significant predictors of voting turnout. Those with a college degree, for instance, have an 80 percent voter turnout rate, compared to about 60 percent for those without. Additionally, the likelihood of voting increases alongside income, with over 80 percent of citizens earning $150,000 a year or more turning out to vote. These individual characteristics, along with feelings of civic duty and political interest, greatly influence the propensity to vote.