The difference between key performance indicators (KPIs) and metrics is that a key performance indicator is used to measure performance and success. A metric is nothing more than a number within a KPI that helps track performance and progress. So KPIs are measurable values that show you how effective you are at achieving business objectives. Metrics are different in that they simply track the status of a specific business process. In short, KPIs track whether you hit business objectives/targets, and metrics track processes.
So a metric is a measure, or quantification, of an action, so metrics are the numerical values associated with the activities. Website traffic, number of clicks, average conversion value - these are all samples of metrics. So a metric can be both a single measure (such as a count) or a calculated value.
However a Key performance indicator (KPI) is a measurable value that shows the progress of a company’s business goals. KPIs indicate whether an organization has attained its goals in a specific time frame. KPIs are the measure the success of specific activities used to meet business goals - measured against a specific target or benchmark, adding context to each activity being measured.
Few KPIs from Project Management perspective are as follows:
1. Overdue project tasks / crossed deadlines
2. % of overdue project tasks
3. Missed milestones