After a brief discussion on the history of decision-making, this chapter focuses on metrics for justifying investment in information systems and technology and for measuring business and management performance. The discussion of metrics is linked to current practices in decision support systems and focuses on the needs for future systems. With several examples drawn from contemporary practice, we introduce implementation guidelines for DSS development incorporating new metrics that go beyond ROI and Balanced Scorecard-like measures. Suggested guidelines include simplicity, selectivity, a focus on research and learning, and benchmarking. These guidelines suggest that future metrics to support decision support systems should be grouped into meaningful categories and tied more closely to system architecture.