What is an “imputed” indicator – and for which countries were these imputed statistics used?

For countries for which only one HDI indicator is missing, the HDRO estimates the missing value using an alternative source or a cross-country regression model. For example, mean years of schooling (MYS) for Liechtenstein is based on MYS of neighbouring Austria. For 11 countries—Antigua and Barbuda, Cabo Verde, Dominica, Eritrea, Guinea Bissau, Grenada, Kiribati, Seychelles, St. Kitts and Nevis, St. Vincent and the Grenadines, and Turkmenistan — mean years of schooling was estimated by a cross-country regression model. Expected years of schooling was estimated by cross-country regression for ten countries—Bahamas, Dominica, Equatorial Guinea, Haiti, Libya, Papua New Guinea, South Sudan, Tonga, Trinidad and Tobago, and Vanuatu. For three countries—Saint Kitts and Nevis, Eritrea and Grenada — mean years of schooling was estimated by a cross-country regression model.