‘Leaving no one behind’ (LNOB) constitutes one of the core principles underpinning the
2030 Agenda for Sustainable Development. We propose a complementary fuzzy logic
approach to identify countries left behind in human development and each of its
dimensions. We find that the countries left furthest behind at the beginning of the century
were those that most reduced gaps with respect to better performing countries after two
decades. Nevertheless, we cannot clearly speak of convergence in human development.
There are notable exceptions, such as the Central African Republic, Liberia, Yemen, Haiti
or Venezuela, which despite the improvement in their Human Development Index
worryingly increased their gaps in human development dimensions relative to the rest of
the world. Our analysis highlights significant advantages of using the proposed fuzzybased LNOB approach to incorporate the moral imperative of leaving no country behind
in the measurement of human development.
