According to Professor Steven Cohen, a well known researcher of American Jewish demographics (he is a professor at HUC-JIR and Director of the Berman Jewish Policy Archive at Stanford University), the American Jewish Orthodox population is exploding, while the non-Orthodox Jewish population is declining very quickly.
In an opinion piece in the Forward (entitled, "American Jews Will All Be Orthodox Soon") Professor Cohen notes that if we analyze the ages of current American Jews, we find that Among Jews aged 56-73, the Orthodox comprise 5% of all Jews. Among Jews aged 28-45, we make up 15% of the total population. And among children aged 0-17, the Orthodox are a whopping 27% of the total.
These numbers reflect both the growth of the Orthodox population and the decline of the rest of the Jewish population. This is an area in which I have a personal interest and I have studied it for many years.
For example: In 1991, New York Area Jewry was overwhelmingly Conservative and Reform: together 70 percent of all Jews in the metropolitan New York area identified themselves as one of these. In only 11 years, by 2002, this total dropped to 54 percent — a drop of over 25 percent. (All statistics are based on the New York Jewish Population studies of 1991, 2000 and 2011, sponsored by the Jewish Federation of New York.)
On the other hand, in 1991 Orthodox Jewry made up only 13 percent of the Greater New York Jews according to the survey. By 2002 this rose to 19 percent, an explosive rise of almost 50 percent! By now the Orthodox are probably at least a third of all the Jews living within the boundaries of New York City. They outnumber both Reform and Conservative Jews there. In not so many more years they will outnumber both of them combined.
One aspect that is not often studied is the average age of the groups of Jews. The latest numbers I have are for New York City Jews in 2011. At that time, both the average and median age of Reform Jews in the New York City area were 58. For Conservative Jews both were 61. But for Orthodox Jews the average age was 46 and the median age was 41, consistent with the known fact there were more younger Orthodox Jews than older.
The published results from 1991
Moreover, these figures are available from 1990 and 2002 so that we can see the trends as they change over time. In 1990 the average and media ages of Reform Jews were around 40. In 2002 the average age of Reform Jews was 52.49 and the median age was 51. This is unusual as it shows that the Reform population was statistically static and it was aging by a year as each year passed. By 2011 the ages both increased to 58, a somewhat slower rate but still very high. By today, at the end of 2016, these figures should be well over 60 years. Conservative Jewry shows basically the same trends.
In stark contrast, the Orthodox average and median ages declined over those 20 years, from an average of 48.68 and a mean of 43 in 1990, to an average of about 46 in 2011 and a mean of 41 as we noted earlier.
This means that Conservative and Reform Jews are on the way out. They are or will soon be retired and will not much actively participate in Jewish life.
Anecdotally, the prominence of Orthodox Jews in America has risen sharply in recent years, as they occupy Cabinet positions, serve as ambassadors and even run for president of the United States. Improbably, the president-elect's daughter and son-in-law are Orthodox Jews.
According to my research, the general numbers for American Jewry are, from an Orthodox perspective, distorted. Sociological studies count people based on how they see themselves. So if someone reports that he or she is Jewish, the sociologist will mark them down as such. (This is a reasonable policy from their perspective.)
However the Orthodox perspective on Jewish identity is considerably more restrictive than this. Even bypassing the issues about various conversions being recognized or not, we would certainly not count someone as Jewish if his or her mother was not Jewish and they never underwent any conversion.
The published results from 2011
However, for many years both the Conservative and Reform movements have officially embraced unconverted spouses of Jews and even have special reachout programs to attract them and their families. In some cases they willingly accept unconverted people who do not have a Jewish spouse but wish to join their synagogues (and pay membership).
Those running the survey cast a wide net and try to be as inclusive as possible. Thus, it turns out that over 25 percent of American Jews as counted by these surveys fit this category. That is, their mothers were not Jewish and they underwent no conversion at all, not even a Reform, Conservative or invalid Orthodox conversion. The overall numbers, from and Orthodox perspective, are correspondingly smaller, and the Orthodox proportions are higher.
Professor Cohen notes that the participation and engagement of non-Orthodox Jews declines sharply with age. The younger Jews are not engaged with Jewish organizations (religious and secular) and even have little special feeling about Israel.
Among young non-Orthodox Jews, the group growing fastest is that of Jews with no religion. Professor Cohen notes that the trends of non-Orthodox Jews are similar to those of American Catholics and Mainline Protestants. All show declining adherents and participation, as "no-religion" Americans have become the largest religious "denomination" in America.