The purpose of this paper is to build on previous research (Eto et al. 2012) by using more comprehensive econometric analysis techniques to evaluate the long-term reliability of U.S. electric utilities. This analysis explores a range of factors which are correlated with reliability in order to answer the following questions: (1) Are there utility-specific differences in reported electricity reliability?; (2) How is reliability affected by the installation or upgrade of an automated outage management system (OMS)?; (3) Are deviations in annual sales correlated with changes in utility reliability?; (4) How do basic weather observations affect the frequency and duration of system outages?; (5) How do annual transmission and distribution expenditures affect the frequency and duration of system outages?; (6) Do utilities that follow IEEE-recommended reliability data reporting standards report significantly different reliability from those who do not follow IEEE data reporting standards?; and (7) Are there unexplained trends in reported electricity reliability over time?