Models, Ideal Types and Definitions
Referring to a religion as a minority religion does not merely imply a statistical minority. Within the UK, Roman Catholicism and Methodism may have a smaller membership than the Church of England, yet, unless we are concerned primarily with counting members, they are not normally referred to as minority religions, a term that can suggest that they may not be such full members of society as more ‘mainstream’ religions are.
Western scholars of religion have distinguished between four ‘ideal types’ of religion.  The exact emphases vary from scholar to scholar, but the model distinguishes between ‘church’ and ‘sect’, which consider their religion uniquely legitimate, compared to the ‘denomination’ and ‘cult’ which have a more pluralistic outlook. It also typifies the ‘sect’ and ‘cult’ as being (unlike the ‘church’ or ‘denomination’) in tension with society.  The ‘sect’ is often depicted as a schismatic group that emerged from a more established religion, while the ‘cult’, is characterised as a more innovative group, frequently focused around a charismatic leader. 
Using these types, one might compare the Church of England as a ‘church’ with Methodism as a ‘denomination’, Jehovah’s Witnesses as a ‘sect’, and an assortment of movements, such as Scientology, as a ‘cult’. The types can serve to illuminate process whereby a sect might split away from a church, but after some time become more accommodating to and accommodated by society through a process called ‘denominationalisation’. It might be noted that the Church of Jesus Christ of Latter-day Saints (the Mormons) can be classified as a Church in Utah, a denomination in England and a sect in Russia.
Minority religions could, by these criteria, be classified as a denomination, sect or cult. However, in popular usage the terms cult and sect have come to mean little more than a religion the speaker does not like, and which is associated with a number of negative generalisations. To label a group a ‘cult’ can suggest its members believe and do things no ‘normal’ person could believe or do, and it has frequently been assumed members could not have converted of their own free will, but must have been subjected to ‘brainwashing’ or mind-control techniques.
This negative image of a cult has been exacerbated by some tragic and widely publicised occurrences, such as the suicides and murders of over 900 followers (including more than 200 children) of Jim Jones’ People’s Temple in the Guyana jungle in 1978. Later horror stories have included the release of deadly sarin gas in the Tokyo underground in 1995 by Aum Shinrikyo, the 9/11 bombings in 2001 of the Twin Towers by Al Qaeda and, most recently, the terrorist attacks of ISIS and other groups.
But such examples represent only the tip of a very large iceberg. Inform holds information about over 5,000 different religious organisations, more than 1,000 of which are currently active in the UK.  A considerable majority of these were unknown in the West before World War II and are, therefore, sometimes referred to as new religions, although many had existed for centuries in other parts of the world.
In an attempt to research and describe minority religions from an objective perspective which did not start from an assumption that they were ‘bad’, scholars now prefer to use the term ‘new religious movement’ (NRM) to describe what others might refer to as cults or sects. There is, however, no generally agreed definition of an NRM (just as there is no generally agreed definition of ‘religion’). Some refer to NRMs as religions that have appeared in the West since the mid-twentieth century; others mean a religion in tension with society, however old it might be. Another approach is to define NRMs as religions that have a predominantly first-generation membership. This has such advantages as (a) being relatively easy to identify without assuming other characteristics, (b) being applicable at any time or place (so the disciples of Jesus as described in the New Testament, were first-generation members of the NRM Christianity), and (c) highlighting the changes that take place if and when the first generation gets replaced by second and subsequent generations.
But however they are defined, there are three things one can say about NRMs: first, one cannot generalise – they can differ from each other in every conceivable way; secondly, they perform few, if any, actions that have not been performed by older religions; and thirdly, if one wants to understand NRMs, one cannot look at them in isolation from the rest of society.
That said, however, there are certain characteristics that one might look for in a first-generation religion. First, by definition the membership consists predominantly of converts, and converts tend to be more enthusiastic than those born into their religion. Secondly, they are disproportionately drawn from an atypical section of the population – this might be the politically oppressed, e.g. white middle-class adults (such as Unificationist converts) or young, unemployed black men (such as the Rastafarians). Thirdly, there is frequently a founder/leader who wields charismatic authority over his or her followers, and is thereby unbound by rules or tradition and likely to be unpredictable and unaccountable to anyone. Fourthly, at least some NRMs tend to have relatively dichotomous world views, with very clear boundaries being drawn between, for example, right and wrong and ‘them’ and ‘us’. Fifthly, NRMs are frequently treated with suspicion or fear. And sixthly, NRMs tend to change more rapidly and radically than older, more established religions.
9.A useful tool for comparative purposes, the Ideal Type is not ideal in an evaluative sense, but defines a phenomenon by accentuating certain aspects in ways rarely found in reality. Weber, Max. 1949. The Methodology of the Social Sciences. Editors E.A. Shils and H.A. Finch. New York: Free Press.
10.McGuire, Meredith B. 2002. Religion: The Social Context. Belmont CA: Wadsworth, Pp. 151ff.
11. Stark, R., and W.S. Bainbridge. 1996. A Theory of Religion. New Brunswick, NJ: Rutgers.
12. Inform http://www.inform.ac is an educational charity founded in 1988 with the support of the British government and mainstream Churches to provide up-to-date, reliable, evidence-based information about minority religions.