But on the merits alone, Lamm’s observation, while arguable impolitic, is not without basis. Notwithstanding the current strength of Reform Judaism, America’s largest Jewish denomination, its future is cause for some concern. There’s the well known and recently updated study that showed that 100 Reform Jews will result in 10 identifying Jews in four generations. Conservative Jews did a little better, with 29. Ultra-Orthodox, by contrast, yield 3,401 Jews after four generations.

I rest my case.

Among many flaws, the study does not in any way account for denominational switching, which—if you look at any REAL study of American Jewry—is SUBSTANTIAL and particularly affects the number of Orthodox. The 2001 NJPS found that of all Jews who said their denomination at birth was Orthodox, only 40% said they are now Orthodox.  That was by far the highest out-migration of any denomination.

Remember that fundraising-letter controversy of a month ago where JTA claimed the mantle of journalism over the blogosphere?  Do a little fact-checking about that “study” you link to as fact.  (Maybe call it “infamous” rather than “well known.") Otherwise, don’t bother trying to differentiate JTA from the rest of the blogging screeds.