ANNEX I. >> M  etadata sheets on selected indicators Convention on the Rights of the Child, art. 27 (3); and Convention on the Rights of Persons with Disabilities, art. 28 (1). Indicator 11 Ratio of pupils to teaching staff in primary and secondary, public and private, education institutions [e.g., table on the right to education] Definition  The ratio of pupils to teaching staff or the pupil‑teacher ratio is the average number of pupils per teacher at a specific level of education in a given school year, based on headcounts of both pupils and teachers. Teachers or teaching staff include the number of persons employed full time or part time in an official capacity to guide and direct the learning experience of pupils, irrespective of their qualifications or the delivery mechanism, i.e., face to face and/or at a distance. This excludes educational personnel who have no active teaching duties (e.g., heads or principals who do not teach) and persons who work occasionally or in a voluntary capacity. Rationale  The ratio of pupils to teaching staff is an important indicator of the resources that a country devotes to education. To a limited extent, the indicator can also be interpreted as reflecting a qualitative aspect of a country’s education infrastructure. Teachers are the most important resource in an educational environment, particularly at the primary and secondary levels. The pupil‑teacher ratio provides a measure of pupils’ access to teachers, and thus reflects an important element of the provision that the State may have to make to meet its obligations on the realization of the right to education This indicator is a process indicator related to the “curricula and educational resources” attribute of the right to education. Method of computation  The indicator is computed by dividing the number of full‑time equivalent pupils at a given level of education by the number of full‑time equivalent “teachers” at that level and in similar types of institutions, in a given school year. Some data collection methods include counts of all teaching staff and, since all teaching staff include staff with administrative duties and both full‑ and part‑time teachers, comparability may be affected as the proportion of part‑time teachers may vary from one country to another. Data collection and source  The main source of data at the country level is administrative records on school enrolments and staff maintained by the relevant public agencies. The Institute for Statistics of the United Nations Educational, Scientific and Cultural Organization (UNESCO) compiles and provides national information on the pupil‑teacher ratio for both primary and secondary education, based on data reported by national education ministries or national statistical agencies. The information is gathered through yearly questionnaires and is made available by the Institute two years after the reference year. While information on this indicator is not currently collated on a disaggregated basis for public and private schools at the international level, it should generally be available at the national level and could be useful to report in instances where there may be significant differences in the quality of public and private education in primary and secondary schools. Periodicity  For most countries the pupil‑teacher ratio is available annually. Disaggregation  It may be useful to disaggregate the data for teaching staff and pupils by sex, age, economic and social situation, ethnicity, minority, indigenous, colour, language, religion, national or social origin, migrant, and disability. Beyond the disaggregation referred to in the indicator itself (primary/secondary, public/private), further disaggregation may be necessary, for instance by Human Rights Indicators 157