A good friend sent this to me, I thought it was a good definition.
Dashboards Monitor and Measure Processes. The common industry perception is that a dashboard is more real-time in nature, like an automobile dashboard that lets drivers check their current speed, fuel level, and engine temperature at a glance. It follows that a dashboard is linked directly to systems that capture events as they happen and it warns users through alerts or exception notifications when performance against any number of metrics deviates from the norm.
Scorecards Chart Progress Toward Objectives. The common perception of a scorecard, on the other hand, is that it displays periodic snapshots of performance associated with an organization’s strategic objectives and plans. It measures business activity at a summary level against predefined targets to see if performance is within acceptable ranges. Its selection of key performance indicators helps executives communicate strategy and focuses users on the highest priority tasks required to execute plans.
Whereas a dashboard informs users what they are doing, a scorecard tells them how well they are doing. In other words, a dashboard records performance while a scorecard charts progress. In short, a dashboard is a performance monitoring system, whereas a scorecard is a performance management system.