Common terms in cost assessment of health interventions
| Terms | Descriptions |
| Fixed costs (FC) | Costs that do not vary with the quantity of output in the short run (eg, 1 year) and may vary with time, rather than the level of output. Could include: |
| Development costs | |
| Intervention development planning (eg, meetings, consulting) | |
| Intervention materials development (eg, creation of educational videos) | |
| Start-up costs | |
| Facilities and infrastructure set-up (eg, equipment and technology installation, furniture) | |
| Hiring costs | |
| Initial training | |
| Operational costs | |
| Labour | |
| Salary, wages, fringe benefits of staff (eg, administrative support, operations management, supervision, programme monitoring) | |
| Volunteer time | |
| Training Equipment | |
| Depreciation of durable goods | |
| Variable costs (VC) | Costs that vary with the level of output. Could include: |
| Operational costs | |
| Labour | |
| Salary, wages, fringe benefits of staff (eg, intervention delivery staff, service labour) | |
| Volunteer time | |
| Materials, supplies (eg, testing kits, postage, educational materials) | |
| Travel | |
| Mileage, gas | |
| Total costs (TC) | Total intervention cost (ie, the sum of all cost categories during the study time horizon): TC=FC+(VC×Q) |
| Average cost (AC) | Average cost per unit of output, such as cost per person served (ie, total costs divided by the total units of outputs): AC=TC/Q |
| Marginal cost (MC) | Cost of producing an additional unit of output (ie, total cost after producing an extra unit of output minus the original total cost): MC=(TC of Qn+1)–(TC of Qn) |
| Opportunity cost | Cost of forgoing the next best alternative use of a resource; the value of the resource had it been used for another productive activity. |
Q, quantity of output, such as persons served.