Saturday, October 25, 2014

Mid-decade update

(Crossposted to Jewschool.)

Now that we're into Cheshvan, it's time for a mid-decade update!

Four years ago, we noted that for the entire decade of the 2010s, there are only two patterns of Hebrew years:  Rosh Hashanah on Monday and on Thursday.  This means that most or all of the fall holidays are on weekdays for the entire decade, and 4 of the last 5 years have included a string of 3 "3-day yom tovs" for the 2-day yom tov folks.

We made the following prediction:  This decade, and especially this half-decade, will see lots of 2-day-yom tov people switching over to 1 day.

Now that the 2010s are half over (in regard to major Jewish holidays), it's time to assess whether this prediction has been accurate so far.

I'm not claiming that this is scientific data collection methodology, but I'm calling for anecdata.

In the last 5 years, did you switch from 2-day yom tov to 1-day?  If so, post in the comments.

And to be fair (and to assess, again unscientifically, whether there has been a real shift or just a dynamic equilibrium) we'll ask the opposite question too:  In the last 5 years, did you switch from 1-day yom tov to 2-day?

A few guidelines:
  • If you don't want to out yourself and post under your real name, that's fine, but then please use a pseudonym (not just "Anonymous") so that we can count unique individuals.
  • Switches to or from 0 days of yom tov don't count (that's measuring something different).
  • We're asking about what you do when you're outside of Israel.
  • We're not asking about Rosh Hashanah.
  • We realize that people aren't always completely consistent, and that practices can vary based on the situation.  Answer based on which practice you primarily identify with.

Thanks for your cooperation!  I'll ask the same questions in 5 years, if blogs are still around.

Saturday, April 05, 2014

Internal monologue

Lonely (and whiny) internal monologue upon the latest of many recent widely discussed articles on streams of American Judaism:
"It's great that this discussion is happening, but why is no one writing about my form of Judaism?"
"Because I don't have time to blog anymore."

Wednesday, October 09, 2013

"Independent minyanim" in 1985

A late-breaking update has been added to this old post on the history of the term "independent minyan".  Scroll down to the bottom.

Thursday, October 03, 2013

Notes on the Pew survey

(Crossposted to Jewschool.)

The Pew Research survey, “A Portrait of Jewish Americans,” released yesterday, has received a lot of attention in both the Jewish and the mainstream media. I don’t have anything more to add about the results themselves; many pages have already been written in the last 48 hours. But after reading both the data and some of the spin, I have several comments about what we can and can’t conclude from the data.

1) Orthodox Retention

There has been discussion of the retention rates among various age cohorts of Orthodox Jews, i.e. what percentage of Jews raised as Orthodox currently identify as Orthodox. This percentage is significantly higher among the younger age cohorts than among the older cohorts, leading some to conclude that the Orthodox world is more effective at retention at the present time than in the past.

This conclusion is not supported by the data. Let us consider an alternate hypothesis: The attrition rate of Orthodox Jews has remained constant over time. What results would we expect from this hypothesis? The percentage of raised-Orthodox Jews who currently identify as Orthodox should decrease with increasing age (since older people have had more time to leave Orthodoxy), and this is in fact what we see in the data. But we can be more precise in our predictions from this model: The percentage should decay exponentially.

To test this, I fit the numbers to an exponential curve. I made the following assumptions and simplifications (which were quick-and-dirty, but you can try it yourself with different assumptions): I assumed that 100% of Orthodox-raised Jews identified as Orthodox at age 18 (and all attrition occurred after this). I collapsed each age range (e.g. 18-29) to a single data point at the center of the age range. For the highest age group (65+), I assumed it went up to 90.

The result was that the data fit the exponential very closely (R2 = 0.9932), with an attrition rate of about 2.4% per year:

Of course we can’t conclude that there has in fact been a steady rate of attrition either! My point is just that this would be consistent with the data. There are many possibilities – it would also be consistent with the data that everyone who leaves Orthodoxy leaves during their 20s (which would mean that the attrition rate is in fact much lower for the current 20somethings). There’s just no way to determine from these data (which only provide a snapshot of the present time) which model is correct, without data from past generations.

2) Denominational Identification

First of all, the exact question asked on the phone survey was “Thinking about Jewish religious denominations, do you consider yourself to be [RANDOMIZE: Conservative, Orthodox, Reform] something else, or no particular denomination?” (Kudos to the survey writers for randomizing the order of denominations! Shame on the report writers, who did not randomize or alphabetize the order when reporting the results.) So the survey participants were asked about denominational self-identification. Any discussion of the results (whether by Pew itself or by the media) that references denominational affiliation is not accurately reporting the results; there was no question that asked about denominational affiliation.

This distinction is particularly important when it comes to the “Reform” label. Reform Jewish identity is complex and multifaceted, but there are many people for whom the “Reform” label doesn’t mean affiliation with the Reform movement or affinity to Reform Judaism as a system of religious belief and practice; it means “I don’t do anything; I’m Reform[ed].”

This phenomenon is supported by the survey data themselves: 20% of the “Jews with no religion” category (i.e. people who first described their religion as “none”, then answered in response to a followup question that they consider themselves Jewish aside from religion) identified as “Reform”. Of all the Jews who identified as “Reform”, only 34% are synagogue members (so this category does not represent URJ members), and 16% said that they never attend Jewish services (including high holidays).

This means that any results about the “Reform” population have to be taken with a grain of salt, and can’t be translated into generalizations about Reform Judaism or the Reform movement. This goes both for the results that make Reform look bad (e.g. low rates of Hebrew literacy or of seeing being Jewish as very important) and for the results that make Reform look good (being the largest denomination and having the highest “retention” rate).

What we can conclude is not that Reform Jews are likely to be Jewishly inactive in various ways, but that people who are Jewishly inactive in various ways are much more likely to identify as “Reform” than any of the other denominational labels.

3) Intermarriage

The intermarriage rates are based on the percentage of the “net Jewish” population, i.e. those who consider themselves Jewish. Now that there has been substantial intermarriage for more than one generation, there are many people who were raised by one Jewish and one non-Jewish parent and who have gotten married themselves. Such people may identify as Jewish or as non-Jewish, or may be on the fence. It’s probably fair to assume that people who are on the fence are more likely to marry non-Jews than people who identify unequivocally as Jewish.

Therefore, in the same way that unscrupulous school administrators can improve their average test scores and graduation rates by getting rid of students who are likely to lower those stats, Jewish leaders who want to lower the intermarriage rate may be motivated (consciously or otherwise) to alienate intermarried families so that their children don’t identify as Jewish (so that if those children go on to marry non-Jews, it won’t count as an intermarriage). This may explain the behavior of some parts of the Jewish community.

Note also that the intermarriage rates by denomination are based on current self-identification. If someone was raised Orthodox and then marries a non-Jew, it is unlikely that s/he currently identifies as Orthodox. Given that, the most surprising part of the 2% Orthodox intermarriage rate is that it’s so high – these are Jews who are married to non-Jews and continue to identify as Orthodox.

Finally, the intermarriage statistics are only for current, intact marriages. Therefore, the apparent rise in intermarriage over time may be somewhat misleading. The report notes that “some research indicates that “in-marriages” (marriages between people of the same religion) tend to be more durable than intermarriages; if this is the case, then the percentage of intermarriages in the 1970s and 1980s may have been higher than it appears from looking only at intact marriages today.”

4) Money

One result that raised some eyebrows was that only 76% of Ultra-Orthodox respondents refrain from using money on Shabbat (suggesting that 24% do use money on Shabbat). The explanation for this may be simple: The question wording was “Do you personally refrain from handling or spending money on the Jewish Sabbath, or not? [INTERVIEWER NOTE: IF ASKED, “REFRAIN” MEANS TO NOT DO SOMETHING]” This double negative may have been confusing (especially for respondents whose first language wasn’t English), and the clarification was only for people who requested it. Some significant number of Ultra-Orthodox respondents may have answered “no”, thinking they were saying “No, I don’t handle or spend money on Shabbat.”

Tuesday, January 29, 2013

Response to H'zon

(Crossposted to Jewschool.)

I hope everyone had a great New Year of the Trees! Several days ago, the Jewish environmental organization H’zon put up (and sent to their email list) a blog post defending their practice of incorrectly referring to the holiday as “Tu B’Shvat”. (h/t to commenter Joel for “H’zon”.)

A review of why this is incorrect: In Hebrew, a word may not begin with two shevas. (A sheva is the vowel that looks like a colon underneath the letter; depending on context, it is pronounced either not at all or like the English schwa.) Therefore, if one of the prefixes b-, k-, or l- is placed on a word beginning with a sheva, the prefix letter gets a chirik (the “ee” vowel, represented by a single dot under the letter) instead of a sheva. For example, the name of the month of Sh’vat (uniquely among all the Hebrew months) begins with a sheva, so when the prefix B- is attached to the month, you get Bishvat (or BiShvat or biShvat or Bi-Shvat or BeeShvat — however you want to write it).

To be clear, this is a Hebrew grammar issue; it is NOT a transliteration issue. The issue has nothing to do with the choice of which English characters are used to represent each Hebrew letter and vowel — the same issue would come up in vocalized Hebrew, in which בִּשְׁבָט is correct and בְּשְׁבָט is incorrect. (In unvocalized Hebrew, of course, the difference is invisible.) As a parallel, suppose your organization sent out an email (in English) around the new year (the tree one or any other one) saying “Shanah tov!” If someone then responded “Actually, it should be ‘shanah tovah’, since ‘shanah’ is a feminine noun, so it should take a feminine adjective”, you wouldn’t reply “Hey, you’re entitled to your preference, but there’s no right or wrong way to transliterate Hebrew into English characters.” It should be obvious that such a reply would be a non sequitur, since noun-adjective agreement is obviously unrelated to transliteration – nothing would be different if the email had been in Hebrew and said שנה טוב, and then was corrected to שנה טובה.

In short, anyone who says this is a transliteration dispute either doesn’t understand the issue (and should defer to those who do) or is intentionally obfuscating.

With that in mind, here’s the story so far:

Around this time last year, I wrote a blog post, “The War on Tu Bishvat”, enumerating and responding to the top five rationalizations for “B’Shvat”/”B’Shevat”, and explaining why they are without merit, followed by a second blog post, “Tu Bishvat Halls of Fame and Shame”, which laid out who was on each side of the issue. I then had some unfortunate online interactions with H’zon, during which one of their staffers acted unprofessionally, and I wrote it up in a third blog post, “Hazon sinks deeper into the hall of shame”.

If you haven’t read those three blog posts (or even if you have), read them now before proceeding further.

H’zon didn’t read them before responding, and as a result, most of the points they make in their defense were already anticipated, and already responded to, a year ago in “The War on Tu Bishvat”. In fact, I think they managed to hit all five. So I’m not going to rehash all of those points again (only some of them).

They referred to me only as a “Jewish blogger”, and didn’t call me out by name (which I appreciate, since this isn’t about me), and likewise I’m not calling out the author of the H’zon post by name (even though the post was signed), because I otherwise respect this individual, and want to make it clear that this isn’t personal.

To be fair, I understand that H’zon may be under a lot of stress right now: they recently merged with the Is’bella Fr’dman J’wish R’tr’t C’nt’r, and it appears to already be a rocky marriage, since H'zon has just doubled down on “Tu B’Shvat”, while IF remains committed to “Tu B’Shevat” (which is even more wrong: while “Tu B’Shvat” may be marginally defensible as a transcription of how some people pronounce the name of the holiday, “Tu B’Shevat” doesn’t even have that going for it). Still, we’ll leave H’zon and Is’bella Fr’dman to work out their own differences; this post is targeted more at those who might be inclined to follow H’zon’s lead and change their style from the correct to the incorrect name of the holiday.

The first half of H’zon’s response is a long and irrelevant digression about academic transliteration, stating that “a certain kind of foolish consistency of academic transliteration can become the hobgoblin of little minds.” The opening paragraphs of this post (and item #1 in “The War on Tu Bishvat”) should make clear why this line of argument is a red herring. Those who are defending Tu Bishvat aren’t insisting on consistency in transliteration, or on any particular transliteration scheme, but only on the rules of Hebrew grammar. H’zon’s attack on the academic transliteration straw man suggests that either they don’t understand the grammatical issue (which is unlikely, because the later part of the post indicates that they do) or they are writing to appeal to those who don’t understand the issue.

H’zon then goes on to outline its reasons for spelling it “Tu B’Shvat”:
1. Finding a way in English to give a sense of the grammar/structure of the Hebrew. My problem with the “correct” transliteration in this instance is that “Bishvat” doesn’t in any way convey to a non-hebrew speaker that בשבט – b’shvat – is a prefix followed by the Hebrew month of Shvat. Tu B’Shvat is, to my mind, a much clearer conveying of what’s going on in the Hebrew than Tu Bishvat.
The idea that one must violate Hebrew grammar in order to convey the sense of Hebrew grammar is certainly a strange one, and one that we would never think of implementing in English. (“Yes, I realize that in a technical sense, ‘went’ would be more academically ‘correct’, but ‘goed’ helps convey that it’s the past tense of ‘go.’”)

And this violation is also entirely unnecessary. As mentioned in item #4 of “The War on Tu Bishvat”, there are plenty of grammatically correct ways to indicate that בשבט is a prefix followed by a month: BiShvat, biShvat, Bi-Shvat, bi-Shvat, Bi’Shvat (if you just can’t quit that apostrophe), Bee-Shvat, and many more. (All of these options, including the incorrect B’Shvat, go above and beyond what would be provided by Hebrew itself, which makes no indication that the bet is a prefix. But as long as English allows for capital and lowercase letters, and punctuation within a word, I agree with H’zon that there’s no reason not to take advantage of these features.)
In addition, properly speaking the first vowel in the word is a long e sound (bee-), although most Hebrew speakers slur that a bit in modern pronunciation. While the proper academic way to represent this vowel is the letter i, in spoken English bi- is never pronounced as bee (think about the words bit and bite). Furthermore, most words in English with bi- as a prefix pronounce it as a long vowel, such as in bilateral, which is not at all what is intended. Therefore, Tu B’Shvat represents a transliteration that a/ is easy to read, b/ visually sets apart the prefix, and c/ allows those not familiar with Hebrew grammar to approximate the typical Hebrew pronunciation.
H’zon can’t seriously think that English speakers outside of academia would have difficulty pronouncing “Bishvat”. Plenty of English words have the letter i pronounced as “ee”. Most of these are loan words from other languages rather than coming from Anglo-Saxon roots, but they have become common English words all the same. No English speakers have trouble pronouncing machine, radio, pizza, or bikini. (Ok, most of those words don’t have the string “bi”, but is there any reason to think the consonant b should make a difference?)

Furthermore, English-speaking Jews who are accustomed to seeing Hebrew transliteration (even if they don’t speak Hebrew) know that it’s a standard convention to read the vowels as in Spanish (or other languages with similar vowel sets), rather than as in English words of older vintage. H’zon knows this – on their own website they feature programs called Siach and the Shmita Project. They don’t feel the need to spell these as “S’ach” or “Shm’ta”, nor do they appear to be concerned that English speakers might pronounce the i vowels as “eye”. (And I’ve never heard anyone pronounce the commonly used nickname of the Israeli prime minister as “bye-bye”.)

Finally, if an English speaker doesn’t pronounce the i in Bishvat as “ee”, the next likeliest pronunciation would be the first syllable rhyming with “fish”, which would still be closer to (or at least no farther from) the Hebrew pronunciation than any reading of “B’Shvat” would be.

For all these reasons, H’zon’s claim that “B’Shvat” would lead readers to the correct pronunciation, while “Bishvat” is an ivory-tower affectation (like “qydwš”) that would baffle non-academic English speakers, is simply not plausible.
2. Common usage. On Google, tu b’shvat and tu b’shevat have between them 619,000 hits, whereas tu bishvat and tu bishevat have 431,600. (This may change over time: if ten years from now the grammar-police succeed in imposing bishvat or bishevat, then there would be some argument for us to cross-over; even then, I’d prefer not to lose a sense of prefix and month, as well as reflecting how a non-native Hebrew speaker pronounces English vowels.) Tu bee-shvat in comparison has fewer than 50 hits.
3. It’s how it was spelled when I was a kid. This last is of course the least defensible academically, and the most persuasive personally. I’ve been celebrating Tu B’Shvat since I was a kid, and I’ve been to or hosted Tu B’Shvat seders every year since 1986; and along the way, I’ve always spelled it – and mostly seen it spelled – Tu b’Shvat.
The idea that practices based on ignorance are justified because most people are ignorant, or because people have been ignorant for a long time, is a troubling epistemological stance for an environmental organization to encourage. Presumably H’zon generally wants its constituents to rethink widespread and longstanding problematic practices on their merits, rather than to leave those practices in place based on their popularity and longevity. But with this irresponsible blog post, H’zon has given its epistemological stamp of approval to anyone who might say “Most Americans drive everywhere and eat factory-farmed meat, and that’s what I’ve been doing since I was a kid. And ‘meat’ gets a whole lot more Google hits than ‘tofu’. So why should I even think about switching to anything different, when that would put me in the minority? If ten years from now the treehugger police succeed in imposing a carbon tax, then there would be some argument for me to think about biking or public transportation, but even then I’m not sure I’d do it.” The thread of anti-intellectualism that runs through H’zon’s response, from the “academic transliteration” straw man to the “grammar-police”, is also playing with fire: this attitude aids and abets those who say “Sure, a bunch of egghead professors may tell us that the climate is changing, but why should I believe them instead of Fox News?”

H’zon then has the audacity to quote President Obama on climate change: “The path will be long and sometimes difficult. But America cannot resist this transition. We must lead it.” Leadership, whether on climate change or on Hebrew grammar, means having the fortitude to do what is right (which includes admitting past mistakes) and to bring others along by example, rather than following the crowd. On this count, H’zon has failed. Rather than wait passively for others to correct themselves on this issue, H’zon has the power (and therefore the responsibility), as a pillar of the Jewish environmental movement, to lead that change. They have chosen to waste this power.

Perhaps H’zon will never evolve on this matter. If so, this post isn’t directed to H’zon, but to all of the environmentally-minded organizations and individuals who respect H’zon (even though this respect is unwarranted on this issue) and follow its lead. Think about the qualities that you want to embody in order to face this generation’s greatest challenges. If H’zon won’t provide leadership on this issue, you have the power to begin on your own.

Thursday, January 24, 2013

January Madness results!

(Crossposted to Jewschool.)

The final Knesset election results are in! (This guide may help if you can’t remember which party is which.)
  1. Likud Beiteinu 31
  2. Yesh Atid 19
  3. Labor 15
  4. Habayit Hayehudi (The Jewish Home) 12
  5. Shas 11
  6. United Torah Judaism 7
  7. Hatenua 6
  8. Meretz 6
  9. United Arab List – Ta’al 4
  10. Hadash 4
  11. Balad 3
  12. Kadima 2
  13. Otzma Leyisrael
  14. Am Shalem
  15. Aleh Yarok (Green Leaf)
  16. Koach Lehashpia
  17. Eretz Hadasha
  18. Hayisraelim
  19. Greens
  20. Dor Bonei Haaretz
  21. Chaim Bechavod
  22. Da’am – Workers Party
  23. Tzedek Hevrati
  24. Achim Anachnu (We Are Brothers)
  25. Pirates
  26. Kulanu Haverim Na Nach
  27. Economics Party
  28. Mitkademet Liberalit Democratit (Leeder)
  29. Or (Light)
  30. Brit Olam
  31. Hatikva Leshinui
  32. Moreshet Avot
(“But wait!” you say. “This is only 32 parties! I thought there were 34!” That’s right. The breakaway haredi party Netzach dropped out last week, having resolved its differences with United Torah Judaism. Atid Echad (One Future) also dropped out two days before the election – apparently pornography wasn’t at the top of anyone’s list of issues in this election.)

So first of all, congratulations to everyone who participated in January Madness 2013! Given how unpredictable Israeli elections can be, it takes a lot of courage to make a prediction and put it out there in public. No one correctly predicted all 120 Knesset seats, but everyone got some of them right.

But even more so, congratulations to the winners!!! Both Lev Polinsky in New York NY and Eyal in Israel correctly predicted 112 of the 120 Knesset seats. (While no one predicted that Yesh Atid would win 19 seats, Lev Polinsky came the closest, with 15.)

So we had to go to tiebreakers. On the first tiebreaker (which party that doesn’t make it into the Knesset will come closest?), Lev Polinsky guessed Am Shalem and Eyal guessed the Greens. Since neither picked the right-wing Otzma Leyisrael (instead, both of them incorrectly predicted that Otzma Leyisrael would win Knesset seats), we go to the second tiebreaker (which party will come in last place?). Again, no exact matches: Lev Polinsky picked Kulanu Haverim, and Eyal picked Eretz Hadasha. So now we go back to the first tiebreaker. Since Am Shalem (2nd place among the parties that didn’t make it in) did better than the Greens (7th place), Eyal wins second place, and Lev Polinsky is the 2013 January Madness champion!

Here is a message from our champion (who also wins a copy of the Comic Torah):
I am thrilled to have won, and I will print and display my winner’s certificate proudly alongside my HRH Assassin winner’s certificate – also won under BZ’s supervision. I hope he gets a job as the head of the Multi-State Lottery Association soon.

I enjoyed having an excuse to learn about all the marginal Israeli parties, like Kadima. I look forward to repeating this exercise in a few months.

Finally, I have been negligent in making my suggested contribution, so if people want to make suggestions for places to contribute in the comments, I am all ears.
And a message from our runner-up, who also wins a copy of Ghettoblaster:
I was really surprised to win. All i did was look at Wikipedia’s list of predictions, and basically used that. I changed it a bit, adding a bit to the right, which might explain why i missed 8. But i still never expected to get 93⅓%!

They had a warning that it might not add up to 120 seats, so to check, i wrote a short program to prepare it for addition – replace whitespace with +; then i pasted into Google. I’m actually a pretty good programmer; i created and the associated projects from scratch; and i also host a forum for programmers at Speaking of TypeINT, i’m sure that some readers have needed to type in Hebrew, but were unsure how to. TypeR, by TypeINT is the perfect solution.

I hope that the 19th Kenneset proves some early predictions wrong and doesn’t end a disaster.
Finally, honorable mention goes to everyone who got the tiebreaker questions right. On the first tiebreaker question, congratulations to James Bier in Tucson AZ, David in Philadelphia, David Meyer in College Park MD, Mike Schultz in Karmiel, Tzemah, and Eliana in DC, all of whom picked Otzma Leyisrael as the top party not to make it over the threshold. On the second question, congratulations to David W. Eisen in Bet Shemesh and Ethan Tucker in Bronx NY, who predicted that Moreshet Avot would come in last. (I never could figure out what Moreshet Avot’s story was, and apparently neither could anyone else, except for 461 voters.) And since we didn’t get the news about the two parties dropping out in time to remove them from the contest entrance form, we’ll also give honorable mention to James Bier in Tucson AZ (again) and Itamar Landau in Jerusalem, both of whom picked One Future to come in last place (since one could argue that 0 is less than 461). (The most popular choice for this question was the Pirate Party. They weren’t even in the bottom seven! The lesson is never underestimate pirates.)

Thanks for playing, everyone! The next Knesset election will be Tuesday, November 7, 2017 (yes, that’s also Election Day in US jurisdictions that hold elections in odd-numbered years), unless elections are called earlier than that (which they almost certainly will).

Thursday, January 17, 2013

Thanksgivukkah FAQ

(Crossposted to Jewschool.)

As many of you know by now, November 28, 2013, will be both (American) Thanksgiving and the 1st day of Chanukah! The possibilities are endless: deep-fried turkey; latkes with cranberry sauce and gravy; pumpkin sufganiot; I’m sure you have more in mind. This week an article by Jonathan Mizrahi on this calendar issue has been making the rounds. It has some excellent graphs illustrating both the rarity of Thanksgivukkah in our present era and the long-term drift of the calendar that will make Thanksgivukkah impossible in the future, but it somewhat overstates its primary claim that Chanukah and Thanksgiving are “a once in eternity overlap”. This FAQ answers some questions that this article has inspired in various other forums, and corrects a few nuances.

Many thanks to Stephen P. Morse for creating an excellent tool to answer calendar questions quickly (though if he’s reading this, I’d love to see the capability of going beyond 9999 CE, and of distinguishing between Adar and Adar I), and to Remy Landau for providing the raw data on the Rosh Hashanah drift (though if he’s reading this, what’s with the popup ads?).

If you have questions that aren’t answered here, we’ll try to answer them in the comments (and if there are a lot, we’ll put together a sequel).

1. What is causing the long-term drift in the calendar?

You’ll notice from Mizrahi’s graph that the Jewish holidays shift significantly from one year to the next (like seasonal variations in the weather), but also (on average) slowly drift later over long time periods (like climate change). The year-to-year shifts are because the Hebrew calendar is primarily a lunar calendar, and 12 lunar months are approximately 354 days – much shorter than the solar year of ~365.25 days. Without any correction, the Jewish holidays would continue to move ~11 days earlier every year. (This is what happens with the Islamic calendar, in which every year is 12 lunar months without exception, so over several decades the Muslim holidays traverse the entire solar year.) In order to keep the Jewish holidays roughly aligned with the solar year (so that Pesach is always in spring, etc.), an month is added every few years, so Jewish “leap years” have 13 lunar months instead. As the Greek astronomer Meton discovered, 235 lunar months (=19*12 + 7) are approximately equal to 19 solar years, so if we put the calendar on a 19-year cycle, and add an extra month to 7 out of every 19 years, it mostly works out.

BUT NOT EXACTLY. 235 lunar months add up to 6939 days 16 hours 595 parts. (In Jewish calendar math, “parts” are the basic subdivisions of an hour, instead of minutes and seconds. There are 1080 parts in an hour, so 595 parts is about 33 minutes.) In the Gregorian calendar, 19 solar years (on average) are 6939 days 14 hours 626 parts. That’s about a 2-hour difference. So the Jewish holidays (on average) shift about 2 hours later during each 19-year cycle, which adds up to a full day every 231 years.

2. Is this an issue of Julian vs. Gregorian calendars?

Not really. 19 Julian years (on average) are 6939 days 18 hours. So if the Gregorian calendar is closest to the actual solar year, the Jewish calendar is doing better than the Julian calendar at approximating it (but still not well enough). (Think of it this way: By definition, the Julian calendar deviates from the Gregorian calendar by 3 days every 400 years. The Jewish calendar deviates by slightly less than 2 days in the same time period.)

3. But there’s some mechanism in place to correct this drift before it gets out of hand, right?

Nope. If no action is taken, the Jewish calendar will continue to drift later and later, until Pesach is in summer, Rosh Hashanah is in winter, etc. And it’s not clear how any action could be taken, since there’s no Jewish pope or Sanhedrin or any sort of body empowered to act on behalf of the whole Jewish people. But on the bright side, (as Mizrahi mentions) if we wait tens of thousands of years, we’ll loop all the way around to where we started.

The Catholics do have a pope, and so even though Easter is on a similar 19-year cycle, they’ve instituted corrections to keep it from drifting. Easter and Pesach usually coincide, but in the years when they’re a month apart instead, let’s just say it’s not Easter’s fault.

4. If we did take action to fix the calendar drift, what would that look like?

Generally speaking, over the long term, we’d need a way to have (very) slightly fewer leap years. I’ll get into specific proposals in a future post.

5. If November 28 is the earliest possible Chanukah, does that mean all the other holidays in 2013 are the earliest they can be?

Yes! We’re also getting the earliest Purim (February 24), Pesach (March 26), Shavuot (May 15), Rosh Hashanah (September 5), and the other fall holidays.

However, because of the aforementioned calendar drift, this is true only locally, for the present couple of centuries. The earliest Rosh Hashanah used to be September 4 (which means Purim on February 23, and so on for the rest of the holidays), but that happened for the last time in 1766. The last September 5 Rosh Hashanah (until we loop all the way around, of course) will be in 2089; after that, the earliest will be September 6.

6. Chanukah is never early or late – it always starts on the 25th of Kislev! Ha ha!

Yuk yuk yuk. You’re very clever, and showing your allegiance to Jewish time rather than to the surrounding culture. But the solar year is an actual physical thing, not an arbitrary convention of the secular calendar (even if the months of January, February, etc., are arbitrary) – it corresponds to the earth’s orbit around the sun, and therefore to many readily observable features of the seasons. The architects of the Jewish calendar understood this, and that was why they instituted leap years, to make sure the season-dependent Jewish holidays ended up in their proper seasons. The concept of “the holidays are early this year” would have been very familiar to the rabbis of the Talmud (even if their response of “Do you think we should add an extra Adar?” would be unfamiliar to us).

7. Is it true that Thanksgiving has never fallen during Chanukah before?

It’s true that, since Thanksgiving became a national holiday in 1863, no day of Chanukah has fallen on the 4th Thursday in November. But Thanksgiving wasn’t always on the 4th Thursday in November: originally, it was on the last Thursday in November (which could be either the 4th or 5th Thursday, depending on how many Thursdays were in November). The change happened under President Franklin D. Roosevelt, starting in 1939. (The motivation was to start the Christmas shopping season a week earlier, to help stimulate the economy. Can you imagine a time when the Christmas shopping season never started before Thanksgiving?) The original range for Thanksgiving was November 24-30; the current range is November 22-28.

And sure enough, there were two Thanksgivukkahs in the late 19th century, both on the 5th Thursday in November. Thursday, November 29, 1888, was the 1st day of Chanukah, and Thursday, November 30, 1899 was the 4th day of Chanukah.

8. If November 30 was the 4th day, that means Chanukah started on November 27! How is that possible?

Good question! After all, September 5 is the earliest possible Rosh Hashanah (and indeed, September 5, 1899, was Rosh Hashanah), and has been since 1766. And as we know from 2013, September 5 Rosh Hashanah corresponds to November 28! What’s the deal?

The answer is that, while all the holidays between Adar and Cheshvan have a fixed relationship (since all the months in between have a fixed number of days), Chanukah is different, since Cheshvan can have either 29 or 30 days. In “applesauce years”, Cheshvan has 30 days, and Chanukah begins on the same day of the week as Rosh Hashanah (as it will in 2013). In “sour cream years”, Cheshvan has 29 days, and Chanukah begins one day earlier, on the same day of the week as Shavuot. 1899 was a sour cream year, so Chanukah began one day earlier, on November 27.

However, Shavuot can never fall on Thursday, so Chanukah can never fall on a November 27 Thanksgiving.

9. Have there been any other November 27 Chanukahs since then?

No. 1899 was the last one, and will be the last one (until we loop around again).

10. Is it true that Thanksgiving will never again overlap with Chanukah?

Never say never. As Mizrahi points out, it will happen again in 70,000 years or so, when the calendar loops all the way around.

11. Ok, but seriously, what about during our (or our grandchildren’s) lifetimes?

After 2013, if we ignore what happens 70,000+ years in the future (and assume the rule for the date of Thanksgiving stays the same), Thanksgiving will never again fall completely during Chanukah.
However, Chanukah begins at sundown, and my family does Thanksgiving dinner in the evening (though I know not everyone does). And though the 1st day (or any other day) of Chanukah won’t fall on Thanksgiving again in the near-to-medium future, we’ll have a couple more instances when the first night of Chanukah is on Thanksgiving night: November 27, 2070, and November 28, 2165. (The first of those will be just before my 91st birthday, and I hope to be celebrating with my grandchildren (and maybe great-grandchildren), just as my son and I got to celebrate Thanksgiving this year with my nonagenarian grandfather.) After 2165, that’s it.

The partial Thanksgiving-Chanukah overlap happened once before, on November 28, 1918. Perhaps some of our older readers remember this?

12. Wait, I wasn’t alive in 1918, and I think I remember Chanukah starting on Thanksgiving night.

No, you don’t. You’re thinking of 2002, when Chanukah started on Friday night, November 29 (the night after Thanksgiving).

13. Have we had other November 28 Chanukahs in recent memory?

Yes, most recently in 1994. But that year, Chanukah began on Sunday night (Thanksgiving was November 24). After 2013, we’ll have it again in 2032, when Chanukah begins on Saturday night (following Thanksgiving on November 25).

14. Is it fair to say that Thanksgiving repeats on a 7-year cycle?

It’s not strictly true, since the 4-year Gregorian leap year cycle interferes with this. But Mizrahi’s point is about long-term averages, so his statement that “[y]ou would therefore expect them to coincide roughly every 19×7 = 133 years” is valid to within reasonable precision. The point is that the probability of Thanksgiving falling on any of the 7 allowed days is roughly equal, and is uncorrelated with the 19-year cycle (since 7 and 19 are both prime numbers).

15. While we’re on the subject of early Jewish holidays coinciding with American holidays, can Rosh Hashanah fall on Labor Day?

Yes! Labor Day is the first Monday in September, so it can fall anywhere from September 1 to 7, and part of that range is in the allowed range for Rosh Hashanah. It won’t happen this year, when Labor Day is September 2 and Rosh Hashanah is September 5. The last time was September 7, 1964, and the next time will be September 6, 2032.

As for Rosh Hashanah starting on Labor Day evening (so that 2-day Rosh Hashanah observers get a 5-day weekend), the last time was September 5, 1994, and the next time will be September 6, 2021.