Why did the report shift from human development categories based on HDI values to one based on quartiles?
The previous cut-off points were set as absolute values, and were inevitably somewhat arbitrary. With the new classifications, the approach is explicitly relative — based on quartiles. The new classification also reduces the amount of variation within each group: previously the medium human development group ranged from 0.500-0.799, whereas now the effective range is 0.488-0.669. It does however mean that some countries have entered in a lower classification this year – even if they continue to make progress—this is the case for Bangladesh, Ghana, Kenya and Nepal for example. In these cases we would stress focusing on the change in the HDI value over time (as per Table 2), and underline that the classifications are relative, not absolute. The low group is the bottom 42 countries; medium next 42, and so on, while the high and Very high are in the top half – medium and low in the bottom half.
