Metric is a measurement of success or failure.
A KPI (Key Performance Indicator) is usually expressed as a metric (or measure) compared to a target value. It may also include a status or trend indicator. An example would be Year to Date sales compared to Plan or Scrap Rate compared to Prior Period Scrap Rate. A KPI is a metrics, but metrics is not necessarily a KPI.
Matrix is a data representation and data collection mechanism Matrix can be dashboard and other summarized data report.
