Definition: Facebook’s cost per result metric breaks down the amount spent per impression/conversion or other metric that formed the basis or objective of a campaign.
How it’s used: Cost per result enables you to gauge how cost-efficiently you reached your objective(s) for a campaign. It can then be used to compare the performance of different campaigns which share the same objective.
Cost per result can be affected by many factors, including target audience, creative and schedule.
Cost per result is calculated by dividing the total amount spent by the number of results (e.g. reach, clicks, conversions, video views).