The index of health service coverage is computed as the geometric means of 14 tracer indicators. The tracer indicators are as follows, organized by four broad categories of service coverage:
I. Reproductive, maternal, new born and child health
- Family planning: Percentage of women of reproductive age (15−49 years) who are married or in-union who have their need for family planning satisfied with modern methods (SDG indicator 3.7.1, metadata available here)
- Pregnancy and delivery care: Percentage of women aged 15-49 years with a live birth in a given time period who received antenatal care four or more times
- Child immunization: Percentage of infants receiving three doses of diphtheria-tetanus-pertussis containing vaccine
- Child treatment: Percentage of children under 5 years of age with suspected pneumonia (cough and difficult breathing NOT due to a problem in the chest and a blocked nose) in the two weeks preceding the survey taken to an appropriate health facility or provider
II. Infectious diseases
- Tuberculosis: Percentage of incident TB cases that are detected and successfully treated
- HIV/AIDS: Percentage of people living with HIV currently receiving antiretroviral therapy
- Malaria: Percentage of population in malaria-endemic areas who slept under an insecticide-treated net the previous night [only for countries with high malaria burden]
- Water and sanitation: Percentage of households using improved sanitation facilities
III. Noncommunicable diseases
- Hypertension: Age-standardized prevalence of non-raised blood pressure (systolic blood pressure <140 mm Hg or diastolic blood pressure <90 mm Hg) among adults aged 18 years and older
- Diabetes: Age-standardized mean fasting plasma glucose (mmol/L) for adults aged 25 years and older
- Tobacco: Age-standardized prevalence of adults >=15 years not smoking tobacco in last 30 days (SDG indicator 3.a.1, metadata available here)
IV. Service capacity and access
- Hospital access: Hospital beds per capita, relative to a maximum threshold of 18 per 10,000 population
- Health workforce: Health professionals (physicians, psychiatrists, and surgeons) per capita, relative to maximum thresholds for each cadre (part of SDG indicator 3.c.1, see metadata here)
- Health security: International Health Regulations (IHR) core capacity index, which is the average percentage of attributes of 13 core capacities that have been attained (SDG indicator 3.d.1, see metadata here)
The index is computed with geometric means, based on the methods used for the Human Development Index. The calculation of the 3.8.1 indicator requires first preparing the 14 tracer indicators so that they can be combined into the index, and then computing the index from those values.
The 14 tracer indicators are first all placed on the same scale, with 0 being the lowest value and 100 being the optimal value. For most indicators, this scale is the natural scale of measurement, e.g., the percentage of infants who have been immunized ranges from 0 to 100 percent. However, for a few indicators additional rescaling is required to obtain appropriate values from 0 to 100, as follows:
- Rescaling based on a non-zero minimum to obtain finer resolution (this “stretches” the distribution across countries): prevalence of non-raised blood pressure and prevalence of non-use of tobacco are both rescaled using a minimum value of 50%.
rescaled value = (X-50)/ (100-50) *100
- Rescaling for a continuous measure: mean fasting plasma glucose, which is a continuous measure (units of mmol/L), is converted to a scale of 0 to 100 using the minimum theoretical biological risk (5.1 mmol/L) and observed maximum across countries (7.1 mmol/L).
rescaled value = (7.1 - original value)/ (7.1-5.1) *100
- Maximum thresholds for rate indicators: hospital bed density and health workforce density are both capped at maximum thresholds, and values above this threshold are held constant at 100. These thresholds are based on minimum values observed across OECD countries.
rescaled hospital beds per 10,000 = minimum (100, original value / 18*100)
rescaled physicians per 1,000 = minimum (100, original value / 0.9*100)
rescaled psychiatrists per 100,000 = minimum (100, original value / 1*100)
rescaled surgeons per 100,000 = minimum (100, original value / 14*100)
Once all tracer indicator values are on a scale of 0 to 100, geometric means are computed within each of the four health service areas, and then a geometric mean is taken of those four values. If the value of a tracer indicator happens to be zero, it is set to 1 (out of 100) before computing the geometric mean.