Benchmarking and Normalization

SDG Indicators are characterised by heterogeneous measurement units. This makes it difficult to compare them as well as produce aggregate indicators. Four main steps can be identified to bring all SDG Indicators to a common metrics:

  • identification of the measurement unit (money, shares, tons, etc.);
  • definition of the range within which past and projected indicator values fall;
  • benchmarking, which is set at max-min thresholds derived from policy targets, literature review or current observations;
  • normalization of values in the common range [0, 100].

It is worth noting that, according to their nature, indicators can have either positive (the higher the better) or negative (the higher the worse) interpretations. The normalization steps reconcile these different paths by uniformly applying the convention of the higher the better (a score of 100 coincides with a fully sustainable performance).

APPS Indicator
Normalization Range
Poverty headcount ratio at $1.25 a day (PPP2005) (% of population)
[40, 0]
Prevalence of undernourishment (% of population)
[20, 5]
Physician density (per 1000 population)
[2, 3]
Healthy Life Expectancy (HALE) at birth (years)
[55, 70]
Youth literacy rate ( % of population 15-24 years)
[85, 100]
Annual freshwater withdrawals, total (% of internal renewable water)
[30, 5]
Access to electricity (% of total population)
[5, 100]
Renewable electricity (% in total electricity output)
[5, 60]
Primary energy intensity (MJ / $PPP2011)
[10, 3]
GDP per capita annual growth (%)
[0, 7]
GDP per person employed ($PPP2011)
[5000, 50000]
Employment-to-population ratio (%)
[40, 80]
Manufacturing value added ( % of GDP)
[5, 15]
Total energy and industry-related GHG emissions over sectoral value added (t of CO2e / $PPP2011)
[2, 1]
Palma ratio
[2, 1.2]
PM2.5 pollution, mean annual exposure (micrograms per cubic meter)
[25, 5]
CO2 intensity of residential and transport sectors (t of CO2 / t of oil equivalent energy use)
[1, 0.3]
Material productivity ($PPP2011/ kg)
[0.5, 2]
Net GHG emissions from agriculture, forestry and other land use (AFOLU) sectors per square metre of forest and agricultural land (t of CO2e / sq. m)
[3, 0]
Gap from equitable and sustainable GHG emissions per capita in 2030 (t CO2eq)**
[15, 5]
Marine protected areas (% of territorial waters)
[5, 10]
Terrestrial protected areas (% of total land area)
[5, 20]
Forest area (% of land area)
[10, 50]
Endangered and vulnerable (animals and plants) species (% of total species)
[10, 0]
Corruption Perception Index
[3, 8]
General government gross debt (% of GDP)
[70, 20]
Research and development (R&D) expenditure (% of GDP)
[0.5, 3]
*This indicator is used only in the assessment of Future Sustainability
** The equitable and sustainable GHG emission per capita level in 2030 is computed as the ratio of the median GHG emission level in 2030 according to scenarios that will contain (with likelihood > 66%) the temperature increase below 2°C by the end of the century , i.e. 42 GtCO2 e (UNEP, 2015), and the median estimate of world population in 2030 (UN, 2015).