How To Make Good Decisions Quickly

(I originally posted this elsewhere a year ago, before starting this blog.)

I have some advice on how to make decisions which you may find useful.

I used to have a lot of trouble with decisions. I would treat each one as though making the wrong choice would cost me greatly - even in trivial cases like picking a dish at a restaurant. Obviously, this is a mistake. However, fixing that kind of overthinking isn't simply a matter of seeing the problem... at least, it wasn't for me. I had to figure out exactly how and why being quicker was OK.

No Fear

The first thing to realize is to think about the worst case: what actually happens if you make the wrong call? In the restaurant case, the worst thing that could happen (realistically) is that you don't end up liking your meal as much as you would have liked the other possible meal. OK, that's not a big deal. Heck, even if it's painful to eat, it'll be over in an hour. In the context of your life, it's completely irrelevant.

The only stuff you need to be afraid of is choices that might ruin your life. For example, shooting someone is a bad idea (and that's ignoring the fact that you ruined their life, too). In fact, you might as well make it a policy to not carry loaded firearms around. That simplifies that problem greatly. Another example of something to be careful about is posting stuff on the internets. Even if you remove it later, that information is probably going to be out there forever, because automated programs are constantly following links and grabbing web pages for indefinite storage. Anything with the word 'forever' involved is something you should consider carefully. These are the type of decisions you need to really reflect on. If you think your future self might care about it, that's when you need to really take some time on that choice.

But the rest of the time, when the downside is only temporary, you should be willing and able to choose in a few seconds to a minute, and you should have no fear because there is no need. Now I will explain which choice to take.

Different is Good

Let's get back to the food example, and say I made a bad choice: I don't like what I got. Well, in addition to the temporary pain, there's also a big upside: you now know not to make that choice again! While it may not seem like you've gained a whole lot of knowledge, that small bit of knowledge can really make itself useful over a lifetime. For example, say you visit that fine establishment again and a fellow diner is contemplating trying that same dish. You can now advise him or her to avoid it, and already your bad experience has repaid itself (assuming you enjoy being helpful). Or, perhaps it just saves you a couple seconds every time you have to make a similar decision in the future. That could be worth it too, especially considering you are likely to make that mistake sometime in your long life. Might as well make it early and save time on future decisions, right? Finally, maybe you'll take a moment and tell the cook that your dish seemed lacking, and suggest a way to improve it. That could make a big difference in the profitability of the restaurant! Even though you might feel uncomfortable doing it, that would probably be a big favor to them which you are only capable of due to your mistake. What all this adds up to is the strange fact that it might actually be better to make the "wrong" choice. It's basically really hard to tell. So you don't even need to worry about which dish is better, because that wouldn't even imply that ordering it would be the better choice! Just pick either one. It doesn't really matter.

Anyhow, in this food example we were assuming you hadn't tried either dish before. But say you are choosing which way to walk home from school. There's a way you've taken many times, which you know is good, and another way you've never tried before. Obviously you are going to take the route you always do - it's not even a contest. There is no risk, because you know it will work. If you take the other route, you might get lost, or it might take longer.

Except that those things don't matter in the long run.

You should seriously consider taking the alternate route instead, just because it's different. First of all, getting lost will - in the long run - result in you having extra knowledge about the neighborhood. If you ever get lost there in the future when it's more important, you'll be very happy to have had that experience. Second, what if it's actually quicker, or even just more scenic? Presumably you travel home a lot, so this will save you time over and over again. Maybe that's not likely... but the cost is basically nonexistant and the possible benefit is gigantic.

In general, whenever you do something different, you will gain some knowledge compared to if you had done it the same. That knowledge is much, much more precious than the factors you normally base most small decisions on. Humans have a bad sense of scale and tend to overvalue security. To counteract this, you need to realize that the novelty of a choice is a huge factor in its favor. If you're ever unsure of what to do, do the thing that seems different from the other ones. And even if you are pretty confident of what to do, give variety a chance.

Worrying Doesn't Help

You need to realize that most of the time you are thinking longer about a decision, you aren't actually being constructive - you are just worrying. In addition, you might worry after making you choice, wondering if it was the right one. These worries are useless. For me, they went away as soon as I realized that I could make decisions almost randomly (as described above) and nothing bad would happen. It's a wonderful feeling.

What About Hard Decisions?

One final note: not all decisions can be made quickly. If you're choosing which college to go to or something equally life-affecting, you should think about your choice for several days if possible. Ask your friends and family what they think, and why (that second part is the important bit - the information they have will help you make your decision in a way that an opinion can't). What I usually do with important decisions is just put them on the back burner for a week or two. If you just wait long enough, and don't neglect to gather information, you will eventually wake up and know which choice you want to take.

In Summary:

• Unless it will have severe long-term implication, you don't need to worry about it. Just pick something.

• Favor the choices that stand out as being different.

• Observe the consequences and enjoy yourself.

• Take much, much, much longer for big decisions.

Thanks for reading.

True Story

'Twas the night before Christmas,

The dread of each elf.

It was that afternoon

That I rickrolled myself.

The streets were all covered

With blankets of white.

I was trav'ling to be

With my family that night.

As I crossed o'er the bridge,

Swiftly stepping along,

Had my earbuds plugged in

And my phone playing songs.

I was making my way

From one bus to the next,

But at once the song stopped -

And I stood there perplexed.

I searched for an answer,

My eyes open wide.

Had my buds come unplugged?

Or the battery died?

It lasted a second,

Then music returned,

But I knew right away

I'd been horribly burned.

For the chords wafting up

From my phone to my head

Were no more Harvey Danger

But Rick Astley instead!

As I wondered how anyone

Could do this to me,

I suddenly had

An epiphany.

For only last night

I'd been working alone,

Adding a brand new

Ringtone to my phone.

So it turned out that

Astleyan iconoclast

Was nobody else than

Myself from the past.

I laughed and I danced

Through the fluffy white rain,

And the passers-by probably

Thought me insane.

Why People Underestimate Time

I believe the following post will be useful to people.

So, I played Wits and Wagers recently. This is a trivia game where you're trying to guess the approximate values of somewhat obscure numbers, such as the percentage of solved identity theft cases where the victim knew the perpetrator personally. Everyone writes down their guess, and then everyone bets on who they think is right.

Frequently, no one has any idea what the answer is. If it's a percentage, like the above question, you're going to guess some value between 0 and 100, which isn't too wide a range. But many questions have a much wider possible range of answers. For example, in that game there was one about the gravity on the surface of Jupiter in terms of Earth gravities. Maybe you remember that Jupiter's volume is about 1000 Earths, but forget that gravity is significantly reduced by the larger radius and lower density, so you answer 1000. Well, the actual answer is about 2.5. Your answer of 1000 was off by forty thousand percent! This kind of disconnect is very common when no one has a clue, so usually you're just hoping your guess is in the right order of magnitude. Sometimes, being 10 times too high or too low is still the closest answer.

So let's look at an example of how you'd choose which number to guess. I just made up this question: How many species of arachnids are known (and thought to still exist)?

Well, I certainly wouldn't expect the answer to be below the thousands. And I'm also pretty confident it's not more than in the millions. If I average these two outer boundaries, I get... something like 505,000 / 2 - which is still in the millions. All right, that's kind of stupid. By averaging like that, I'm implicitly assuming that the number is a thousand times as likely to be in the millions than in the thousands, just because there are a thousand times as many whole numbers in the millions! In reality, I think it's about equally likely that the number is in the thousands or in the millions, and I also think it's about equally likely (and more likely) that the number is in the tens of thousands or hundreds of thousands. So it's much better to do a geometric mean.

Instead of calculating (a + b) * (1/2), which is the arithmetic mean, I calculate (a * b) ^ (1/2), which is the geometric mean. That means that the resulting number is right in between a and b multiplicatively: the ratio between a and this number is the same as the ratio between this number and b. In this specific example, a is "thousands" and b is "millions". In fact, I'm going to say that "thousands" is the geometric mean of 1,000 and 10,000, or about 3,200. Similarly, "millions" would be about 3,200,000. Now, the geometric mean of those is 100,000. That seems like a good, middle-of-the-road guess. It actually feels a little high to me, but I also think I have a tendency to underestimate these kinds of things. So I'll see what the answer is now...

Wikipedia says:

It is estimated that a total of 98,000 arachnid species have been described, and that there may be up to 600,000 in total, including undescribed species.

All right! So I was pretty close. Actually, that's insanely close (we're looking at the 98,000 number for this question) - I got pretty lucky.

So. That was probably a long enough intro. My point here is that if you're guessing some unknown value, the geometric mean is a pretty useful tool. It's much more realistic to think you'll be off by an order of magnitude (or some multiple or fraction of one) in either direction, than to think you'll be off by some numeric value in either direction. It's important to note that if you're fairly certain, the arithmetic mean and geometric mean are very similar! The mean of an hour and ten minutes and an hour and thirty minutes is (duh) an hour and twenty minutes. The geometric mean of those numbers is an hour and nineteen minutes and twenty-two seconds. So despite the fact that the geometric mean is frequently applicable, we get away with using the arithmetic mean because the numbers involved are so close together, and so the difference between those methods of averaging is tiny. This is something that probably hasn't occurred to most people. I don't recall ever doing a Story Problem where the answer involved using a geometric mean.

It also brings me to my point. Say I'm estimating how long a time I expect something to take. I guess three days. Now, it may be much easier, and only take one day. Or it may be harder, and take several more days. I don't really know, but I guess "three" regardless.

And, assuming I'm a decent guesser, I'd be too high about half the time, and too low about half the time, and close to right as high a proportion of the time as I could be. The weird part though is that if I'm too low, it's a big deal compared to if I'm too high. If I guess it takes twice as long as it does, I'd be off by a day and a half. But if I guess it takes half as long as it does, I'm off by three days!

Say I'm trying to calculate how long an entire project, composed of ten smaller tasks, will take. I think each task will take about one day, so I add them up and get about ten days for the entire project. This is a mistake. Even though I have an even shot of being too high or too low for each individual task, I am probably underestimating the time of the whole project. For example, let's say that my guesses were half the real value half the time, and double it half the time. That makes the total time of the project 5 * 2 days + 5 * 1/2 days = 12.5 days. It gets even worse if I can be wrong by more than a factor of two, which is quite common when estimating the time to get something done that you've never done before. If I'm off by factors of three instead, that becomes 16.67 days. Consistently off by a factor of four, and I need to raise my over/under more than double, to 20.125.

The reason for this is that geometric means are applicable, but then you're adding the results together. If the last step was to multiply all the task times together, the variance of your guess wouldn't have any effect on the final likely value. Unfortunately, it does. 

If you don't know how long something takes, it will on average take longer than you should expect it to take. This average amount it takes longer is related to the uncertainty you have about how long it will take.

Have fun!*

*It occurs to me that you should endeavor to have absolutely no clue how fun the things you're going to do are. ;)

The Meaning of Life

A Brainteaser

Say there are a bunch of different types of things. Apple, Banana, Car, Door, etc. The different possible combinations of those things can easily be mapped to whole numbers by using binary. For example, maybe 1 means Apple and 1010 (binary) means Door and Banana. If you give me the list of different types of things (with the order of the list implying which binary digit represents each one) and a number, I can tell you exactly which set of things that number represents. "3", given the above list, maps to Banana and Apple, because 3 written in binary is 11.

OK, so that works.

Now what if you introduce the idea that there could be any number of all those things, not just 1 or 0? Like, maybe I have 12 Apples and 44,392,105 Doors. How do you map the non-negative integers to that space, 1 to 1? This is a bit trickier because Base Two works better than Base Arbitrarily-Many.

See if you can figure out a way. It's quite doable.

Worst emergency instructions ever

This was on a bus (the kind you hire that comes with a driver and miniature overhead video screens). If you can't tell, it's right underneath the window. And it's apparently important.

When I first saw it, my thought was: boy, what a poorly made sign. In an emergency, where time is of the essence, people are going to stop and try to understand it and waste seconds, possibly even minutes, determining its meaning. 

Well, it's been over a day now and I still haven't firmly decided on how to interpret it. If you believe to know what it means, please please let me know.

Oh yeah, and here's a clue: the window on the other side has a sticker that's a mirror image of this one.

Dear People Who Yell Out Of Car Windows

I can tell you think that whatever you're saying is very clever. However, from outside the car it sounds like you're saying "ah-oo-eh". Seriously, I can't hear any of the consonants. If you're trying to engender confusion, you are successful.

The last three times you have tried to communicate with me, that's all I got: three syllables. I think. It may just be one syllable plus the Doppler effect. I still have no idea what you said even though, in each case, I've thought about it for a long time.

Would you mind just sticking to really loud music?

Thanks.