What is the cost of an intervention to improve health? This seems like a simple question, just add up the costs. However, some costs are variable and some are fixed. Thus, adding an extra person to an intervention may not equal to the average cost as fixed costs may not increase. Additionally, there may be (dis)economies of scale or scope which may (increase) decrease cost for the marginal patient.

A paper by d’Elbée et al. (2023) aims to create a structure for better capturing cost of health interventions, particularly in low- and middle-income countries (LMIC). Key definitions to consider are:

• Inputs. hospital bed, per field officer, lab reagent, diagnostic test
• Outputs: Measure either per service (e.g., dose of vaccine administered, hospital visit, medical consultation, screening or diagnostic test) or health intervention (e.g., primary health care: health promotion, sanitation and environment health, maternal and child health and family planning, nutrition, immunization and communicable diseases control)
• Outcomes: per beneficiary or per target individual.
• Setting. Per administrative structure (e.g., village, block, health center)

The paper has a very nice mathematical construction of how to measure costs, with key considerations. Relevant figures are shown below.

The full paper is here.