Many data center facilities focus on improving the infrastructure efficiency, measured by PUE (Power Utilization Effectiveness), but a single minded focus on that metric will often yield perverse results, such as low equipment utilization, stranded capacity, and wasted capital. It's the business results that should matter to data center owners, not improvements in imperfect efficiency metrics like PUE. That means a focus on both the cost per computation and the total revenues from computation, detailed analysis of efficiency improvements in both computing and infrastructure, and sensible application of computer simulation tools to understand how changes in information technology deployment will affect the utilization of data center infrastructure over time. This talk will explore a more holistic, business-focused view of data center efficiency grounded in the key performance indicators that should be most important to the companies that own data centers.