The SSI shows at a glance the level of sustainability of countries along three dimensions:

Human wellbeing (HUW)
Environmental wellbeing (ENW)
Economic wellbeing (ECW)

The SSI is structured along the lines of the Triple Bottom Line of social (HUW), environmental (ENW) and economic (ECW) sustainability. HUW consists of three categories based on nine indicators. ENW consists of two categories based on seven indicators. Finally, ECW consists of two categories based on five indicators.All scores are given on a sustainability scale of 1(weakest) to 10 (strongest). There is no overall sustainability score, which would combine the three dimensions.

What's new in version 2?

The development of the SSI started in the early 2000s. Data providers discontinued their service or updated their data over the years. A data update became necessary. Data of smaller countries became available and were expected to be included into the SSI. The need for time series capability grew rapidly. With version 2 of the SSI we meet all these requirements.
The main objective for version 2 was to deliver data for more countries/territories on a yearly baseline in order to better support cross-sectional and longitudinal analyses. In doing this, we kept the statistical quality of version 1 without concentrating on improving it. Some high correlations between a few indicators remained, because their technical meaningfulness is still given.
Although the perception of sustainability changed slighly since the start of the development of the SSI back to the beginning of this century, we haven't changed the alignment of the indicators yet. This will be part of version 3, planned for the closer future.

The SSI is enlisted in EU’s COIN list. Besides the SSI, this list contains only three other index systems covering all three sustainability pillars at once: SDG Index, the Transition Performance Index (TPI) and the Global Sustainable Competitiveness Index (GSCI). In comparison to SSI, GSCI is orientated towards the competitiveness of the economy, TPI concentrates on developments. In contract to all three index system, the SSI delivers time series abilities back to the year 2000 and covers more countries than nearly all of them.