The term NRM comprises a wide range of movements which range from loose affiliations based on novel approaches to spirituality or religion to communitarian enterprises that demand a considerable amount of group conformity and a social identity that separates its adherents from mainstream society. Its use isn't universally accepted among the groups to which it is applied.
Although there is no one criterion or set of criteria for describing a group as a "new religious movement," use of the term usually requires that the group be both of recent origin and different from existing religions.
Debate surrounds the phrase "of recent origin": some authors use World War II as the dividing line after which anything is "new", whereas others define as "new" everything after the advent of the Bahá'í Faith (mid-19th century) or even everything after Sikhism (17th century).
"New" in the sense of "different from existing religions" is considered straightforward in definition but not as much in categorization. Some scholars have a more restricted approach to what counts as "different". For them, "difference" applies to a faith that, though it may be seen as part of an existing religion, meets with rejection from that religion for not sharing the same basic creed or declares itself either separate from the existing religion or even "the only right" faith. Other scholars expand their measurement of difference, considering religious movements new when, taken from their traditional cultural context, they appear in new places, perhaps in modified forms. Examples of these kinds of "new movements" would be the Western importation and establishment of Hindu or Buddhist groups.
NRMs vary in terms of leadership; authority; concepts of the individual, family, and gender; teachings; organizational structures; etc. These variations have presented a challenge to social scientists in their attempts to formulate a comprehensive and clear set of criteria for classifying NRMs.
Generally, Christian denominations that are an accepted part of mainstream Christianity are not seen as new religious movements. However, to some, The Church of Jesus Christ of Latter-day Saints, the Seventh-day Adventist Church, Jehovah's Witnesses, Christian Scientists, Shakers, and even tent revivalists have been studied as NRMs. There are also examples of such groups being characterized as cults, generally by other evangelicals who are hostile to their proselytizing efforts. Certain other groups do not define themselves as religions but nonetheless find some scholars labeling them NRMs.
Debates among academics on the acceptability of the word cult continue. Similarly, no consensus has been reached in the definition of new religious movement among scholars.
An article on the categorization of new religious movements in U.S. print media published by The Association for the Sociology of Religion (formerly the American Catholic Sociological Society), criticizes the print media for failing to recognize social-scientific efforts in the area of new religious movements, and its tendency to use popular or anti-cultist definitions rather than social-scientific insight, and asserts that "The failure of the print media to recognize social-scientific efforts in the area of religious movement organizations impels us to add yet another failing mark to the media report card Weiss (1985) has constructed to assess the media's reporting of the social sciences.
NRMs are diverse in their beliefs, practices, organization, and societal acceptance. Irving Hexham and Karla Poewe have consequently proposed that there are NRMs, particularly those who have gained adherents in a number of nations, which can be understood as forming global sub-cultures.
In general, the number of people who have affiliated with NRMs worldwide is small when compared to major world religions. However, the diversity of NRMs has seen the emergence of different groups in Africa, Japan, and Melanesia.
In Africa, David Barrett has documented the emergence of 6,000 new indigenous churches since the late 1960s. In Japan a number of NRMs based on revitalised Shinto belief, as well as neo-Buddhist and New Age groups, have emerged, some of which originated in the late Nineteenth century in the Meiji Era and others in the aftermath of World War Two.
Around twenty-five percent of the world's distinct cultures are found in Melanesia, spanning the island nations from Papua New Guinea, the Solomon Islands, Vanuatu and Fiji. It was here that the phenomena of Cargo Cults were first discerned by anthropologists and religious studies scholars. The Cargo Cults are interpreted as indigenous NRMs that have arisen in response to colonial and post-colonial cultural changes, including the influx of modernisation and capitalist consumerism.
At the time of their foundation, the religious traditions considered "established" or "mainstream" today were seen as new religious movements. For example, Christianity was opposed by people within Judaism and within the Roman culture as sacrilege toward existing doctrines. Likewise, Protestant Christianity was originally seen—and is still considered by some today—as a new religious movement or breakaway development. There are those who have seen Buddhism as a breakaway innovation from Hinduism.
CESNUR’s president Massimo Introvigne, writes in his article "So many evil things: Anti-cult terrorism via the Internet", that fringe and extreme anti-cult activism resorts to tactics that may create a background favorable to extreme manifestations of discrimination and hate against individuals that belong to new religious movements. Critics of CESNUR, however, call Introvigne a cult apologist who defends harmful religious groups and cults. Somewhat in concurrence with Introvigne, professor Eileen Barker asserts in an interview that the controversy surrounding certain new religious movements can turn violent by a process called deviancy amplification spiral.
Aspects of the guru-shishya (teacher-disciple) tradition are commonly brought forward in disputes related to asserted abuse of authority by gurus and spiritual teachers of new religious movements. In a paper by Anson Shupe and Susan Darnell presented at the 2000 meeting of the Society for the Scientific Study of Religion, they affirm that although the International Cultic Studies Association (ICSA, formerly known as AFF or American Family Foundation) has presented "slanted, stereotypical images and language that has inflamed persons to perform extreme actions," the extent to which the ICSA and other anti-cultist organizations are hate groups as defined by law or racial/ethnic criteria in sociology, is open for debate. See also Verbal violence in hate groups.
The Foundation against Intolerance of Religious Minorities, associated with the Adidam NRM, sees the use of terms "cult" and "cult leader" to suggest that these are to be detested, avoided at whatever cost and see this as the exercise of prejudice and discrimination against them in the same manner as "nigger" and "commie" were used in the past to denigrate blacks and Communists.