Are birthdays evenly distributed across the year? *

[* Two updates appended at the bottom]

It started off as a wasteful exercise by Sharath, where he tracked birthdays for two weeks on Orkut just to see if he knew at least one person born on each day of the year. Something I noticed from his sampling though, was that he had about 2 birthdays / day in his stats … which means he should have roughly 365×2 = 730 friends on his Orkut list. Well, guess what, he has 736 friends on his list! Which suggested that birthdays are sort of evenly distributed across the year.

However, in my personal observation, I’ve seen more people born in the latter half of the year, than the first half. There always seemed to be a ton of birthdays around Oct/Nov rather than, say, April/May. He then went on to make a distribution of birthdays from his class of ’97 – and found that there were 28 birthdays in the first half as opposed to 36 in the second – a small victory for my observation. I couldn’t wait to try this on more stats, so I sampled my own class of ’98 – fairly simple, as we have a database on our yahoo group, and these were the results:

The stats for my class are: 34 born in the first half, and 33 born in the second half – an almost even distribution. Well, so much for my lead :( . But I found an interesting article on the monthly distribution of births in rural India – and guess what ? There is a very clear bias for births in the second half. Which means – high rates of conception in December/January. The paper also refers to a similar increase in conception rates in the United States, attributed to the Christmas (Holiday?) season :) .

So what are the factors you think contribute to an uneven distribution ? Off the top of my head – I’d say

• Astrological ‘luck’ periods – especially for couples in India
• Admission to Kindergarten – I’d assume that more people would like their kids to *just make* the eligibility criteria. For instance, if the cut-off for admission to Kindergarten is ‘Those born in 95’, I’d think that people would think it is an advantage to be born in the latter half of ’95, say Nov-Dec, as they are almost a year younger than those born in Jan, yet they are on the same ‘level’ academically.
• When you get married also influences birth – at least it used to :) .

What are the other reasons you think there are for an uneven distribution of births across a year? Have you noticed a trend amongst your friends?

On another note, I can probably explain why I *feel* more of my friends are born in the latter half of the year – It is simply because I’m born in October and it is more easy for me to remember those that were born in Sep/Oct/Nov than in the earlier half of the year :). I’m not sure what bias to call it. Maybe you can help me with that too.

Update 1: A regular visitor and commentator at this site, Luciferratic gives us some data from a much larger dataset. The chart is astonishing. There is either something wrong with the dataset, or May is the most romantic time of year in the Middle-East ! :)

Update 2: Our instincts are right … there is a reason there are that many January-borns in the data set … Wanna brainstorm on this for a while ? So what you know as of now is : The dataset is huge, it has data of people of all ages, and they are mostly middle-eastern. Now: What possible reason can you think of for this spike in the dataset for January?

Spend some time on this… the solution is elusive but I’m sure someone should be able to figure this out!

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Luciferratic answers this question (along with a bunch of unnecessary apologies!) in his comment here.

Taking January out of the graph, as we know it is likely to have skewed data, the graph is quite even, as follows. There still seems to a bias towards the latter half though (Note: I have not corrected the percentage values in the graph, merely removed the January bar):

What IS the thesis?

( img from http://www.phdcomics.com/ )

Good news from this side. I passed my thesis defense yesterday, and barring a few corrections I’m done with all work for my MS degree. :) The ‘PhD Comics’ strip whose link I’ve posted above has been doing a great service to grad students like me throughout our degrees, so hats off to Jorge Cham, the creator.

While I’m neither a PhD student nor plan to be one anytime soon, ‘the thesis’ did give me a glimpse into research life and really what grad school ought to be about. While tons of my friends opted out of the thesis option earlier on in their master’s degree and went for a more straightforward track to graduation by choosing courses, a few of us stuck on for whatever our reasons were: Most of us, out of passion / interest in our fields, a few others to add value to their resumes, others to see if they were cut out to do a PhD, and even others just to make their Master’s something different from their Bachelor’s degree. Maybe by the power of The Google, this post will help someone decide which to choose, someday.

Some of the obvious cons of the thesis option are:

• Graduation date is uncertain: Sure we’d all love to leave at the end of the 2 year mark, but be ready to stick it out for at least an extra summer, or an extra fall. If you have any hard deadlines for graduating, which you absolutely have to meet, the thesis option is risky.
• Research work is no cakewalk: Whether you are working on something original, or working on something already out there, you still have to have a thorough knowledge of what has been done, and where your work stands in the overall scheme of things. An idea that you are pursuing and implementing for 1-2 months might unexpectedly fail, or you might come across a paper that proves in no uncertain terms that your idea will not work. You have to be willing to scrap months of work pursuing the solution. In other words, failures are a part of the deal
• Your advisor chooses your destiny: If you are stuck with too demanding an advisor, or one who you find hard to approach with your doubts/problems, you are going to be in a rut. Many a times I have come across advisors who are so full of themselves that their students avoid meeting them or asking doubts out of fear that their doubt is too trivial/silly to ask. Of course you need to do your homework before meeting your prof, but you have to find an advisor who is approachable as well. If your only choice is some haughty, demanding prof with dozens of students, who is very demanding, consider opting out !

Some of the pros of doing a thesis are:

• You’ll be a part of something big: The academic world is bursting with ideas, with some of the smartest brains in the world pursuing answers that could change the future. Being a part of that pursuit is something you can be proud of. Making solid contributions in terms of publications would be ideal, but writing a thesis is a contribution as well and serves as a piece of informative literature for whoever is interested in this area.
• You’ll be an expert in something, and will have a ~100 page document to prove it : Spending over a year in a subset of a problem, reading through papers, books, articles and tons of other online material, you have no choice but to end up as an expert in that field, no matter how big or small that field is.
• Job interviews: At job interviews, you will always be asked questions like ‘tell me about a project you have worked on’, or enjoyed. If you were like me, and did not have too awesome a project or a contribution in your academic/professional life prior to grad school, this could be your chance to do something about that.
• Skills that you gain: Searching for and learning how to use a solution used in another problem to work in your problem, brainstorming to find your own solution, reviewing technical papers out there, learning how to explain your ideas in person as well as in writing… these are all skills that you gain along the way, before you even realize it.
• Something to look back on and be proud of: Ask anyone who has done a thesis, and he/she will very proudly speak of his work. True, it’s a daunting task, but it is worth it in the end. Even if the company you join doesn’t value it more than the non-thesis bloke (and this might be the case for lots of companies), what you gained for yourself, the sense of accomplishment, and the contribution of your time/efforts to the progress of science will surely make it worth it.

If anything, doing a thesis is like running a marathon. It’s painful, and you’d rather be lazy and say ‘Nah, I’ll pass’. But there’s no denying that running the marathon will make you stronger… and crossing the finish line will be a moment you will cherish for a long, long time :)