Demographers have had a lot of trouble trying to accurately estimate the Jewish population of the United States. Researchers at Brandeis University have come out with a new study, which has somewhat higher estimates than previous studies. That in itself is likely not of interest to many readers, but the study nevertheless makes for fascinating reading for anyone interested in how demographers studying a population group not included in Census Bureau statistics go about their business, and the pitfalls they face. The fact that one important (NJPS) study claimed that 29% of American Jewish children attend day schools should have raised massive red flags, as that figure is obviously grossly exaggerated if one accepts the broad definition of "Jewish" used by demographers.
One interesting fact I gleaned from the study is that despite the prominence of the ba'al teshuva ("repentance") movement, the "missionizing" of Chabad, and the fact that some Orthodox day schools serve many non-Orthodox children (like me, who spent nine of my twelve pre-college years in Orthodox schools), over 80% of Orthodox Jews were raised Orthodox.