In recent decades, companies have adopted management philosophies such as Just-In-Time (JIT) and Theory of Constraints (TOC) in an effort to improve productivity and, thus, financial performance. This paper describes the use of a comprehensive set of criteria to examine empirically changes in business unit performance, over 3 years, as reported by firms adopting these management philosophies as well as by those using a traditional manufacturing approach. We compare the performance and the change in performance of companies reporting TOC adoption, those reporting JIT adoption, those reporting to have adopted both, and those reporting to have adopted neither (traditional manufacturing). Results indicate that the greatest performance and improvement in performance accrued to adopters of TOC. JIT did not have superior performance or superior change in performance when compared with traditional manufacturing. Change in performance for firms using JIT and TOC simultaneously was negative and trailed all others, though not to a significant degree (except when compared with TOC).