How To Measure Rosh Hashanah Services

My wife and I were speculating on how long last Friday’s Rosh Hashanah service would last. We both figured on two hours, but my wife said, “Services always last longer than you expect.”

My first reaction was to agree, but then I realized that couldn’t be so; it would imply that I didn’t have rational expectations. Having attended services for so many years, my overestimates and underestimates of their duration should balance out: on average, I should correctly estimate their duration.

It’s possible that I might make mistakes if the world changed; and perhaps our new rabbi goes longer than his predecessor. But even with that change, after a few years I should estimate correctly on average. In fact, taking Friday and Saturday together, I was correct: Friday night lasted only one and a half hours, but Saturday’s service lasted half an hour longer than I expected.


Rational...if you have a perfect memory, though.

Going only twice a year isn't very frequent, so it's possible that, come September, you only remember certain aspects of prior year's services, or how the service felt. After all, feelings are generally easier committed to memory than factual details.

As a result, unless one makes note to pay attention to duration and, perhaps, keep records, one's estimation of service duration will be based on those other sorts of memory (well, the sermon's message as I remember it couldn't have taken more then 15 minutes...) or on rough imputation where necessary (well, a reader's kaddish usually only takes a minute or two)[of course, on high holidays, it takes much longer].

So, not irrational, given the sorts of memories people tend to put down.

Though, I don't mean to insinuate that you've been spending the holidays watching your watch.


Boy, we wouldn't want to imply that you don't have rational expectations, would we?

Stephen Jones

Could be that your wife, like most of us, selectively remembers more cases when the thing dragged on than when it ended earlier.


Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law.

Steve Rosen

L'Shana Tova.

Peter from Chicago

I think you are considering the wrong question: It is not how long Rosh Hashanah services last, it is how long they seem to last. That is particularly true in a congregation with poor ventilation or hard seats.

N. Z.

The length of your services (and your tendency to time them) probably has a relation to how much you enjoy sitting through them...

Tim H

Someone has just rediscovered Hofstadter's Law.

Paul Clapham

Cripes -- I see this in my blog reader and by the time I look at it, two people have already mentioned Hofstadter's Law.


And what about Sunday?

For most people I know it lasts as long as they want it to. Most people show up late and leave early.

First of all I'm ignorant to the jewish religion and I might misinterpret the service. I want to ask you if you enjoy these services? If not, in an economical mentality one will ask you what are you doing wasting our time? This way you opportunity cost is enormous since you are loosing your time, the most immense intangible cost. If you enjoy the services, I wonder why you wonder how much time it would last. Since you enjoy it your marginal benefits exceed your marginal cost. Therefore you are rational, since you are thinking at the margin. Also you can't calculate a specific time since the service might vary every year, like a different rabbi, more interruptions, the speed it takes to preform the service, etc. I hope you enjoy these services no matter how much time you've wasted.


While your wife invoked Hofstadter's Law, you may have suffered from Optimism bias, which is the "tendency for people to be over-optimistic about the outcome of planned actions" (, as well as Hindsight bias (


this is an interesting question- for me- I recall so many years of raising this question as a kid. Then I grew up and began reading the book (trying to figure out the message) and listening to the Rabbi's speeches. And I must admit, for the last several years, I have found them real insightful when it comes to the question of the relationship between religion and science. This year was different though. I heard conservative fear creep into the speech. My kid got upset about the hate mongering (so did I) and we left early. I would have yelled out the L word-- as in what is this really about?- but been there and heard that before and it is just plain disrepectful. I heard a while ago from a conservative republican high school friend that this is to be expected ever since Obama became president. I just did not expect it from a Rabbi. Have we forgotten about the separation of church and state and the rationale behind it. The problem is that this Rabbi was acting as a preacher, not a teacher. The other odd thing is, his first speech was about respecting our differences-- So I thought he knew better. He must be struggling with mixed messages from within and without..



Odd. . . all other things being equal, the Saturday Rosh HaShana services should have been shorter than usual, because the shofar service was omitted (the shofar isn't blown on Shabbat). That generally saves about 15 minutes.


My explanation is fact based. Most people who do go to services regularly go on Friday night for Qabbalat Shabbat. This service is radically different from the regular Saturday service, which is based around the weekly Torah reading. I go to services often enough to have well-memorized the Friday service but I only go to a few Saturday services a year.* That can breed estimating error.

*In part because many Saturdays are bar/bat mitzvah services and I don't particularly enjoy hearing kids I don't know reading Torah and then their interpretations.


Even though I don't know much about the Jewish religion, I do have a friend that is a part of it. And, every year on Rosh Hashanah, her parents make her skip school and go to the service. You'd guess that for a teenager, the marginal benefits of skipping school would exceed the marginal costs of going to the service. But, in this case, that conclusion would be wrong. The truth is, that she finds this service to be very boring, and therefore, she finds the opportunity cost of sitting through a long service much higher than sitting through a whole day of school. I don't know if you share her thoughts on it, all I want you to know is that you're not the only person out there trying to guess how long or how short Rosh Hashanah services will be. Maybe one day all religions will have quotas on how many hours of service they can give per year; making it much easier for the people attending them to know how much of their day they'll have to give up. This will result in a more balanced measurement of opportunity costs, and help people make more rational decisions.



Surprisingly, nobody has yet figured out what Hamermesh's guess was... if he's correct "on average" and he guessed 1.5 hours for Friday but was too short by 1.5 hours on Saturday... it means he guessed 3 hours, and the Saturday ceremony was 4.5 hours. The "average error" (-1.5 hours on Friday and +1.5 hours on Saturday gives an average of 0/2 = 0 hours) is "rational" but has a giant variance.


Maybe you're just wrong. Ever think of that?


I prefer to measure RH services by whether or not they motivate me to reconsider my behavior from the prior year, and act better in the coming year. If this motivation lasts a long time, it's good...if not, it's bad.

If you try looking for the meaning of the time, not the meaning AS the time, you'll get more out of it. That starts, btw, by showing up more often than just 3 days/year...


Anon @17

Um, what? He said they both figured on 2 hours for the Friday services. It went 1 1/2 hours (1/2 hour under). Saturday's went 1/2 hour over, so 2 1/2 hours. 4 hours total, or 2 per service, as he said. Did you really think you cracked the code?