I am not convinced of the overwhelming importance of knowing whether American Jewry has in fact declined by some five percent in the decade between 1990 and 2000, but it is unfortunate that the issue has so far been joined only by Mr. Goldberg whose rhetorical capacity far exceeds his statistical insight, and Professor DellaPergola whose capacities are complementary. The unhappy result for the public debate is that Professor DellaPergola's remarks are more exact, but the average non-academic reader can understand Mr. Goldberg much better. It seemed to me that there was an opportunity for me to contribute.

A decline in American Jewry is a certainty. The only questions are how much and, perhaps more importantly, of what sort.

As Professor DellaPergola pointed out, a parallel survey to the National Jewish Population Survey 2000-2001 (NJPS2000) known as the American Jewish Identity Survey (AJIS), which suffered none of the technical controversy that attended the NJPS2000 and which was published more than a year-and-a-half ago, also found a numeric decline in American Jewry, though it pegged the recent number at 5.34 million instead of the 5.2 million found by NJPS2000.

Another important point that has not yet been noted is the consequence of the aging of the Jewish population. The usual figure noted is the median age of American Jewry (the midpoint in the distribution of ages) which rose from 37 to 42 within the single decade between the two most recent surveys. Those unused to the ways of demographics, where change is generally very slow, probably do not appreciate how astonishing such a rapid rise is, and may not understand that it indicates a declining population that is rapidly aging. If a population is stable, its median age should also be stable.

The average age of the American Jewish population is significantly higher, and it rose at the same rate. In 1990 the average age of American Jewry as based on NJPS1990 was 44.56. NJPS2000 found an average age of 49.34.

You need not be a statistician to know that the way of the world is that as people get older they die. However it does take some statistical ability to know and use the rates of death. (For various reasons the average age is better to use for this purpose than the median age.)

According to the United States Life Tables produced by the (US) National Center for Health Statistics, more than 2 percent of the US population dies between the ages of 44 and 49. Since the average age of American Jewry is higher than its median age, that indicates that there are a disproportionate number of older Jews, suggesting that the death rate may really be higher.

The result is that the aging of the population -- which is quite clear from the studies -- accounts for more than a third of the decline found in NJPS2000 and about half of the decline found by AJIS.

The truth is that even if the population held steady, it would not be good news. With a very low birth rate and very rapid aging, the American Jewish population will certainly decline, since death is still a sure thing even though American taxes have recently managed to decline against all previous experience or expectations.

More important than the current numbers is an understanding of the qualitative decline in American Jewry. Here I use the AJIS since it is presented using the identity constructs that were used in NJPS1990. My preliminary analysis of the figures of NJPS2000 indicates no major differences, though comparisons are difficult as many observers have already noted.

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