The 21st Century climate challenge

tinues to advocate improving international dataand plays an active role in supporting efforts toenhance data quality. It works with nationalagencies and international bodies to improvedata consistency through more systematic reportingand monitoring of data quality.Comparability over timeStatistics presented in different editions of theReport may not be comparable, due to revisionsto data or changes in methodology. For this reasonHDRO strongly advises against trend analysisbased on data from different editions. Similarly,HDI values and ranks are not comparableacross editions of the Report. For HDI trendanalysis based on consistent data and methodology,refer to Table 2 (Human developmentindex trends).Country classificationsCountries are classified in four ways: by humandevelopment level, by income, by major worldaggregates and by region (see the Classificationof countries). These designations do not necessarilyexpress a judgement about the developmentstage of a particular country or area. Theterm country as used in the text and tables refers,as appropriate, to territories or areas.Human development classifications. Allcountries included in the HDI are classified intoone of three clusters of achievement in humandevelopment: high human development (withan HDI of 0.800 or above), medium humandevelopment (HDI of 0.500–0.799) and lowhuman development (HDI of less than 0.500).Income classifications. All countries aregrouped by income using World Bank classifications:high income (gross national incomeper capita of US$10,726 or more in 2005), middleincome (US$876–$10,725) and low income(US$875 or less).Major world classifications. The three globalgroups are developing countries, Central andEastern Europe and the Commonwealth of IndependentStates (CIS) and the Organizationfor Economic Co-operation and Development(OECD). These groups are not mutually exclusive.(Replacing the OECD group with thehigh-income OECD group and excluding theRepublic of Korea would produce mutuallyexclusive groups). Unless otherwise specified,the classification world represents the universeof 194 countries and areas covered—192 UNmember countries plus Hong Kong Special AdministrativeRegion of China, and the OccupiedPalestinian Territories.Regional classifications. Developing countriesare further classified into regions: ArabStates, East Asia and the Pacific, Latin Americaand the Caribbean (including Mexico),South Asia, Southern Europe and Sub-SaharanAfrica. These regional classifications areconsistent with the Regional Bureaux of theUnited Nations Development Programme.An additional classification is least developedcountries, as defined by the United Nations(UN-OHRLLS 2007).Aggregates and growth ratesAggregates. Aggregates for the classifications describedabove are presented at the end of tableswhen it is analytically meaningful to do so andsufficient data are available. Aggregates that arethe total for the classification (such as for population)are indicated by a T. All other aggregatesare weighted averages.In general, an aggregate is shown for acountry grouping only when data are availablefor at least half the countries and represent atleast two-thirds of the available weight in thatclassification. HDRO does not supply missingdata for the purpose of aggregation. Therefore,unless otherwise specified, aggregates for eachclassification represent only the countries: forwhich data are available; refer to the year orperiod specified; and refer only to data fromthe primary sources listed. Aggregates are notshown where appropriate weighting proceduresare unavailable.Aggregates for indices, growth rates and indicatorscovering more than one point in timeare based only on countries for which data existfor all necessary points in time. When no aggregateis shown for one or more regions, aggregatesare not always shown for the world clas-222 HUMAN DEVELOPMENT REPORT 2007/2008