A study from the Economic Journal (2010), with the following Abstract:
We use individual-level survey and county-level expenditure data to examine the extent to which Hanukkah celebrations among US Jews are driven by the presence of Christmas. We document that Jews with young children are more likely to celebrate Hanukkah, that this effect is greater for reform Jews and for strongly-identified Jews, and that Jewish-related expenditure on Hanukkah is higher in counties with lower shares of Jews. All these findings are consistent with the hypothesis that celebration of religious holidays is designed not only for worship and enjoyment but also to provide a counterbalance for children against competing cultural influences.
Obvious, perhaps, but still interesting. Hat Tip: Justin Moyer