ACFC/56DOC(2016)001 participation in data collection exercises related to ethnic background must be voluntary. In particular, there must be no automatic inference from a particular indication (for example language use) to another indication (for instance religion, ethnicity) and no assumption of certain linguistic, religious or ethnic affiliations is to be made based on a person’s name or other characteristics.22 16. The right to free self-identification applies in each data collection exercise separately. This means that persons belonging to national minorities must not be required always to self-identify in the same manner. Lists of possible responses to identity-related questions should be open not closed, and the opportunity to express multiple affiliations should be provided explicitly. Given the importance attached in some states parties to the size of a minority population for access to minority rights, multiple affiliations must also not only be recorded but also adequately processed, analysed and displayed. These considerations on the collection, processing and reporting of data must also be applied to other situations (for example school enrolment) that can imply self-identification. 17. In situations where the enjoyment of particular minority rights is linked to numerical thresholds,23 the right to free self-identification further requires that persons belonging to national minorities are informed of the importance attached by the authorities to census and other data collection exercises. The Advisory Committee has therefore systematically encouraged states parties to make all information on the methodology and aim of data collection available in the languages of national minorities, and to include persons belonging to national minorities in the organisation and operation of such processes, particularly in areas where national minorities are settled in substantial numbers.24 18. At the same time, the Advisory Committee has cautioned states parties against exclusively relying on official statistics and figures, as these, for a variety of reasons, may not fully reflect reality.25 Results should be reassessed periodically and analysed flexibly, in close consultation with minority representatives. Authorities should also further avail themselves of other sources of information, including the general labour force and other surveys, as well as independent qualitative and quantitative research available on issues pertaining to the access to rights of persons belonging to national minorities. languages of minority groups”. See, for example, Fourth Opinion on Cyprus, Third Opinions on Estonia and Romania. 22. See, for example, consecutive Opinions on Italy and the United Kingdom. 23. The opening of minority language schools or the official use of minority languages at local level, for instance, may be linked to the actual number of persons belonging to national minorities (see also Part VII). 24. See, for example, Third Opinion on Hungary and Second Opinion on Slovenia. 25. Due to a history of past disadvantage, discrimination or even persecution based on ethnic origin, some persons belonging to national minorities are still unwilling to indicate their ethnic background to any official entity. Misperceptions about the use or apparent dangers inherent in census exercises are sometimes disseminated among minority communities for political purposes with the very aim of preventing them from being counted in high numbers. 9