at facility level, a condition that is often not met. Finally, because of the paucity of records at facility level, some input data are best collected at administrative levels above the actual facility. This may include payroll data, as well as information on the supply of medical and non-medical supplies to the sampled facilities. The collection of comparable data from different levels (e.g., facility and district administration) also provides a basis for verification. Although this type of cross-checks can be very useful, data from different levels are often difficult to reconcile. This may be due to irregularities, or simply due to poor record keeping. If these issues are not anticipated, they can lead to serious problems of interpretation ex post.

# _Costs_

Costs arise from the use of various scarce resources in the production of health services-including patients' time, volunteer services, in-kind donations, etc. Information on costs is an important management tool, and is also useful in determining resource requirements in the process of planning and budgeting. In addition, cost information is a necessary input into the analysis of cost-effectiveness of health care interventions, and may serve as a guide for cost-recovery policies. Finally, information on costs is also important for the evaluation of service delivery performance, in particular efficiency.

Many studies of costs have relied on administrative cost data.<sup>14</sup> We may refer to this as a "top-down" approach. Top-down costing relies on data from central or lower level administration. These data can take many forms, including disaggregated budget allocations or financial records at hospital or sub-national administrative level. While this may be a convenient and relatively cheap way of gathering data, the scope for analysis can be limited by poor quality and insufficient disaggregation. These problems are likely to be particularly severe in developing countries, and for primary health care providers. Also, records of this nature may not exist or be available for NGO or for-profit providers.

In contrast to the top-down approach, the "bottom-up" approach proceeds by quantifying the use of resources at facility level.'<sup>5</sup> In general, it is possible to observe five categories of resources at facility-level: (i) staff time; (ii) supplies, medicines and other consumables; (iii) facility-level administration and overhead expenses (e.g., utilities); (iv) equipment; and, (v) buildings and other physical infrastructure. In addition, there are costs incurred at higher level (e.g., training, supervision, central and sub-national administration), which typically cannot be observed in the facility.

In "bottom-up" costing, a trade-off has to be made between detail and sample size. At one end of the spectrum, a survey can collect data on basic output indicators and on key input use in the production of services. At the other end, a full resource costing considers a more comprehensive range of inputs, and allocates resources used at provider level to specific service categories.' This typically includes some form of time-and-motion study, and a

> 14 Examples of studies based on admmnistrative data include Dor (1994), Bitran-Dicowsky and Dunlop (1993), and Anderson (1980). For a general review, see Barnum and Kutzin (1993) and Wagstaff and Barnum (1989a).

> 15 Costing is based pnmarily on input and price data. However, for some inputs, market prices may not be available, and some values must be imputed in order to find total cost estimates.

> 16 Lewis et al. (1996) comprise a rare example of this approach being used in a developing country. Through a detailed study, they estimate costs for outpatients, inpatient and emergency care, taking into account case mix, clinical norms, indirect and imputed costs, as well as depreciation of physical infrastructure and equipment. They find that although personnel

9