https://www.jcpa.org/dje/articles2/demographics.htm
It means that if there are only eight million Jews who identify themselves as religious, there is an approximately equal division between self-defined non-Orthodox and self-defined Orthodox. However, if there are as many as 9.5 million religiously identifiable Jews, 5.5 million of these identify with Orthodoxy whatever their level of personal observance, giving the latter a 40 percent margin. Many in both groups are nominal in their commitment. Indeed, when nominal observance is factored out, the strength of Orthodoxy is even greater.
Take the Conservative movement, until recently recognized as the largest of the non-Orthodox movements in the United States, and, as a result, probably in the world. Charles Liebman and I have calculated that there are no more than forty to fifty thousand Conservative Jews in the world who live up to the standards of observance set by the Conservative movement. This means that when the Conservative mass is left out, the movement is only the equivalent of a fair sized Hassidic sect. It may be hard to believe, but it is important to note that at the late 1984 wedding of two scions of the Satmar dynasty, the number of Jews packed into a single Long Island stadium for the nuptials equalled the whole body of authentic Conservative Jews. There are seriously committed Conservative Jews who do no live up to those standards, but who are seriously religious in some way. It is hard to estimate how many, but a generous figure would be 36 percent of the movement's membership. Thus, at most there are 400,000 Conservative Jews in the world.
The situation is even harder to estimate with regard to Reform Jews, where standards of observance are low and less binding, but figures similar to those of the Conservative movement are probably in order. Moreover, recent studies of American Jewry show that both movements are in trouble, as increasing numbers of American Jews tend to identify with neither. According to the studies, first generation American Jews tend to identify with Orthodoxy; second and third generation Jews with Conservatism, and, beginning with the fourth generation, with Reform or nothing. This accounts for the decline in Conservative movement membership noted in the recent population studies and the increase in the Reform membership, but the non-identified category in the fourth generation and beyond is around 40 percent.
Orthodox identification, on the other hand, which had been declining precipitously since the late nineteenth century (before that, high Orthodox birthrates offset defections), has probably bottomed out.
Overall, the percentage of Jews who define themselves as Orthodox has grown only marginally, but there has been a transformation in the nature of this group. Many of the nominally Orthodox have fallen by the wayside, and more of those who define themselves as Orthodox really are committed or want to be,. Moreover, the increase in the number of seriously Orthodox is significant, even without taking into consideration the effect of today's high Orthodox birthrate, contrasted with the very low non-Orthodox birthrate.
Today there are approximately 600,000 Orthodox Jews in the
United States, plus another 850,000 in Israel, and perhaps
another 750,000 committed Orthodox in the rest of the world. This
means that there are approximately 2.2 million Orthodox Jews who
are indeed Orthodox - that is to say, wholly committed to
Orthodoxy. That does not include several million semi-observant
Jews who identity with Orthodoxy and will not choose to identify
with a non-Orthodox movement, even if they do not intend to
become more Orthodox in observance in their own lives.
