The Human Development Index has been criticized on a number of grounds including alleged ideological biases towards egalitarianism and so-called "Western models of development", failure to include any ecological considerations, lack of consideration of technological development or contributions to the human civilization, focusing exclusively on national performance and ranking, lack of attention to development from a global perspective, measurement error of the underlying statistics, and on the UNDP's changes in formula which can lead to severe misclassification in the categorisation of 'low', 'medium', 'high' or 'very high' human development countries. Has the HDI been criticized for being biased towards Northern or towards Southern models of development?