"The scope of the classification is all religions and subsets of religions in the world as defined above. In practice, only those religious groups that have a significant number of affiliated persons in Australia are separately identified in the classification structure. However, all other religions are covered and are included in the most appropriate residual category (Miscellaneous, Other, or Not elsewhere classified categories) of the classification. The code structure of the classification also allows the identification of religious groups not separately identified, if such a need arises. (...)
The classification structure also includes a broad group that covers 'Secular Beliefs and Other Spiritual Beliefs and No Religious Affiliation' which could be considered to be inconsistent with the basis of the classification as described above and outside the scope of the religion topic. This broad group has been included for practical reasons and to make the classification more useful. Many statistical and administrative applications need to accommodate the whole range of responses to a question on religion, including personal spiritual beliefs, secular beliefs and the response 'No Religion'."