In many instances, the cost of a service is not a true picture of the actual service provided. For example, when a conference is being conducted, the hotel provides the meeting rooms for free on condition that a certain number of their guest rooms are patronized by the attendees (so the cost of the meeting room is zero for the conference organizers, and the true cost is footed by the members who attend the conference by staying at the hotel - and so those who stay elsewhere do not truly contribute to the cost of running the conference). To get a better handle on the true costs, we may use activity based costing total factor productivity balanced scorecard drum-buffer-rope model