Working hours do not correlate with productivity

A common topic in discussions I have with other graduate students concerns the proper amount of time that we should dedicate to our studies. The topic is relevant to helping us find the optimum work schedule, i.e. one that allows us to both find fulfillment with our studies and graduate in a timely manner. To simplify, let's say that the optimum work schedule maximizes our productivity.

Let's first begin by grouping graduate students into broad categories by their work habits. These categories are by no means mutually exclusive or exhaustive. I do however believe that a majority of graduate students can be placed within at least one of them.

1. The 9-to-5'er: This graduate student treats her research as a regular job. She often works for three or four hour chunks of time, takes a half hour lunch, and generally leaves her work in the office/lab. Five day work weeks are the norm. I believe that this is a somewhat rare work schedule for graduate students.
2. The 8-to-6'er: Pretty much the same as the previous category, except the longer time spent at school means that a graduate student following this work schedule will take more or longer breaks during the day. Some weekend work may also occur. Most students at CREOL fall into this category, myself included.
3. The Night Owl: These students usually don't get to school until 1:00 PM and work until the late hours of the night. They also tend to consume the most coffee.
4. The Stay-At-Home Grad Student: These students typically have advisors who frequently travel or are not present in the lab. They may also have projects requiring a lot of programming and simulation—work that's easily done at home (thank you Remote Desktop).
5. The Stay-At-School Grad Student: Hygiene and a social life are extraneous for these students. Perhaps a product of www.hulu.com and the digital media revolution, the stay-at-school graduate student finds no need to go home when TV can be piped directly to her computer.
6. The Random Worker: If there's work to do, the random worker will spend all her time, day and night, in the lab until it's done. Then she'll spend the next week at the beach. The random worker, like the stay-at-home graduate student, is usually a product of a hands-off advisor. They also tend to share the most in common with undergraduate work habits.

Based on my own observations, I don't believe that there is a strong correlation between the categories above and a grad student's overall optimal output. This is not an exciting conclusion, I know. But what is interesting is that these categories can also be assigned distinct (and, more importantly, different) values that relate to the average number of hours worked in a week. So, the interesting conclusion is that the hours worked has little-to-no effect on grad student productivity.

And don't worry. I have more than my own anecdotal evidence to support my claim. Two articles in Nature [here and here] reported on two separate research groups: one with a brutal schedule and one that strongly supported life outside the lab. Both are successful and well-respected amongst their peers. Furthermore, American researchers (and workers from all occupations) work notoriously more hours a year than Europeans. It might be argued that this does grant the Americans a technological edge, but I have my suspicions. Besides, Europeans are much happier.

I now wonder if the question of the proper amount of time spent working as a graduate student carries any real meaning. It presupposes that there exists some balance that's suitable for everyone, which is clearly not realistic.

And if this article is a bit incoherent, I apologize. I was too busy working this week to think it through thoroughly.