At the community level, we included seven regional dummies (the omitted region being the Mekong Delta), and variables intended to capture the quality and availability of medical services locally.'<sup>3</sup> The latter are not straightforward to define. Several recent studies (Lavy and others 1996; Thomas, Lavy, and Strauss 1996) have included variables capturing whether or not local health facilities had drugs and essential medicines in stock, the numbers of nurses and other medical staff, and so on. This approach is not unproblematic, especially in the present context. In urban areas, it is far from clear which facilities one ought to include in one's assessment of input availability, and indeed most facility surveys undertaken alongside a household survey do not collect such information in urban areas. The VLSS is no exception to this pattern. Furthermore, even in rural areas, there is the scope for missing important potential providers of services, especially in the private sector, which are often not included in such assessments. This is problematic in the case of the VLSS, where the focus in the facility survey (which in any case was only undertaken in 1998) was on commune health centers. Recently, these have diminished in importance, as other providers-including private physicians-have become more important. There is one other problem, which concerns the ability of inventory-type facility surveys to capture the ability of facilities to deliver services. Childhood immunization-which is clearly potentially very important in the context of child survival-is a case in point. In Vietnam, immunization in rural areas is typically delivered through a concerted outreach campaign over a limited space of time, with the necessary equipment (refrigerators, cold boxes, vaccines, etc.) being borrowed or procured for the period of the campaign. An inventory approach is ill-equipped to capture the ability of a facility to deliver such a service.

In the light of these problems, we have opted instead to capture the availability and quality of medical care locally by variables that capture the output of the local health care facilities.'<sup>4</sup> We focus on primary care preventive activities, and include as proxies for the quality of local services coverage rates and average utilization rates of certain key MCH services in the child's village, namely vaccinations (the full course of four key vaccinations, namely measles, diphtheria, pertussis (or whooping cough), and tetanus (DPT)), antenatal visits (2 or more visits), and deliveries by medically trained personnel and deliveries in medical facilities. We computed the rates and the averages from household data on services used in respect of last-born children. Because the number of observations can be fairly small in each village, we computed the nonself (or "drop-out")

> of the MICS data, but the categories in the VLSS data are somewhat different from those in the MICS. For both water and sanitation, we explored using the original categories in the VLSS rather than aggregating into 'safe' dummies, but in the end opted for the present approach which facilitates interpretation of the decomposition results.

> **13** We also included an urban dummy, but dropped it as its coefficient was never significant.

> 1 The variables we use are not entirely under the control of the health system, so the termn "output"-though often used in this context-is a slightly misleading terrm.

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