A metric is a measure usually associated with a performance standard. For example, a key performance measure may be lead-time, but each party needs to agree a common metric to measure what the lead-time is. The buyer may measure the lead-time from the date the purchase order is raised to the date the work is entered into their system as complete. But the supplier may measure the same performance in terms of the date the order is entered into their systems up to the date the good receipt note is signed or the service performed. The parties need to agree a common metric; otherwise they may measure performance differently. See also Key Performance Indicators.