Rules of Thumb, collected, categorized & peer evaluated

January 9, 2008 4:41 PM

Rules of Thumb is a user submitted (and voted upon) collection of the world's greatest rules of thumb for different situations, from playing Blackjack to choosing a bicycle frame.
posted by jonson (38 comments total)

That rule for choosing a bicycle frame is so very, very, very wrong. I don't know blackjack but I'm disinclined to gamble by their rules now.
posted by ardgedee at 4:45 PM on January 9, 2008 [1 favorite]

Different people submit the rules, it should be pointed out; if you disagree with one, it has little bearing on the validity of another.
posted by jonson at 4:53 PM on January 9, 2008

A good place to go to get confused about a subject if you're actually looking for an answer. Just looking at dieting for instance. There must have been 3 rules of thumb for "Maintaining you weight", and all three contradicted each other.

As a source of entertainment value though, I did find the site funny.
posted by herda05 at 5:04 PM on January 9, 2008

As a test of the overall site, is there a way to find out what is the rule of thumb that has the highest overall rating on the scale to 10? Most of the advice is rated in the 5 range.
posted by Admiral Haddock at 5:08 PM on January 9, 2008

I looked up poker and several of the first batch of "rules" contradicted each other.
posted by The Card Cheat at 5:15 PM on January 9, 2008 [1 favorite]

If you're playing improvised music and flub a note or phrase in a scale, repeat the mistake and there is none.

Also works for quagmires.
posted by weapons-grade pandemonium at 5:17 PM on January 9, 2008 [4 favorites]

WHAT NOT TO VACUUM.
Never vacuum up vomit.
posted by cortex at 5:35 PM on January 9, 2008 [1 favorite]

"Different people submit the rules, it should be pointed out; if you disagree with one, it has little bearing on the validity of another."

So it may as well be called "Rules of Dumb".

disclaimer: did not read the link
posted by mr_crash_davis at 5:50 PM on January 9, 2008

I don't really like the format, because it leaves so many questions unanswered. For example, apparently "as a matter of biology rather than sexism, if something bites you, it is probably female."

OK, but if what if something bites me as a matter of sexism?
posted by "Tex" Connor and the Wily Roundup Boys at 5:52 PM on January 9, 2008 [4 favorites]

ardgedee, I have always heard that this is the exact way you choose a bicycle frame.

Stand over the (built-up) frame, with your feet flat on the floor. You should be able to get two fingers between your groin and the top tube.

This rule of thumb is just a guide for not buying a bicycle which is too big.

Smaller bicycles are usually chosen for special reasons; trials, portability, circus performing.
posted by mmrtnt at 5:53 PM on January 9, 2008 [1 favorite]

"...what if something bites me as a matter of sexism?"

Flag it and move on, just like most people will do to your comment.
posted by mr_crash_davis at 5:59 PM on January 9, 2008

Now we know what happens to comments flagged "noise".
posted by mkultra at 6:15 PM on January 9, 2008

Is there some way to get it to sort in descending order? Even manually changing the requests from sort=asc to sort=desc doesn't work.
posted by Pyry at 6:32 PM on January 9, 2008

Both of the blackjack ones are either flat out wrong (assume it's an 8) or incomplete (dealer's up card is a 5 - you should take cards if you have less that 12 and double with a 10 or 11 at minimum)
posted by muddylemon at 6:55 PM on January 9, 2008

To kill an animal with a hammer, draw an imaginary line from its left ear to its right eye and another from its right ear to its left eye. Strike where the lines cross.
Jeff Brown, astronomer, Bloomington, Indiana
posted by Pants! at 6:59 PM on January 9, 2008 [3 favorites]

> I have always heard that this is the exact way you choose a bicycle frame.

It's a popular rule, but it was never accurate, and it's definitely not true with mountain bikes, cruisers, and modern road bikes with compact geometries. These days it's common for the seat tube to be shorter and the seatpost to be longer than on bikes of the past, so the top tube slopes and standover clearance is meaningless.

You ride your bike sitting on the saddle, not on the top tube. Try the distance from the headtube to the seattube instead.
posted by ardgedee at 7:01 PM on January 9, 2008

ardgedee, from your link

It is obvious why you shouldn't have a bike that is too tall to stand over with a reasonable safety margin (although even this sizing practice was not universally accepted for the first 30 or 40 years of the diamond frame.)

We're talking rules-of-thumb, not precise centimeter sizing.
posted by mmrtnt at 7:14 PM on January 9, 2008

After reading a bunch of these, I think we can safely guess where the thumbs were first.
posted by JaredSeth at 7:26 PM on January 9, 2008 [3 favorites]

Despite some popular belief, the idea that the rule of thumb referred to the width of a rod appropriate for wife control seems to be discredited, yet still somewhat disturbing.
posted by caddis at 7:41 PM on January 9, 2008

Well now we know where the "50 things I learned in 50 years" came from. Or is it the other way around?
posted by The Deej at 7:51 PM on January 9, 2008

Never step _on_ what you can step _over_. Never step _over_ what you can walk _around_

I learned this the hard way last year, courtesy of a broken ankle. Either that, or the rule of thumb I should have known was "rocks that look stable sometimes aren't."
posted by DevilsAdvocate at 7:55 PM on January 9, 2008 [1 favorite]

Rule of thumb: Rules of thumb are approximations to good advice, as opposed to good advice.
posted by unSane at 7:59 PM on January 9, 2008 [1 favorite]

As I remember hearing, you want 1"-2" of clearance between your crotch and the top tube. This is to prevent possibly mashing your delicate bits against the tube.
posted by sebastienbailard at 8:08 PM on January 9, 2008

It looks like a lot of the 50 Things I've Learned in 50 Years, from an earlier post today, come from this Rules of Thumb.

Maybe it is just a coincidence or déjà vu on my part.
posted by eye of newt at 8:35 PM on January 9, 2008

OOOooohh. This is shiny . Me like. Sure the bike-fitting rule is out-right wrong for many styles of riding, different types of bikes, and geographic variations.

But, these are not edicts, nor do they so claim. Furthermore any dip can post anything they want , Even me. And we all know how painfull that can be.

Nope, these are exactly what they claim to be. Possibly accurate, rough, guidelines; sometimes useful in some circumstances. It's kinda like astrology; a vague guess, with maybe about a 1/12 chance of occasionally being right.
posted by PareidoliaticBoy at 8:42 PM on January 9, 2008

There must have been 3 rules of thumb for "Maintaining you weight", and all three contradicted each other.

The only rule for 'maintaining your weight' is: input equals output.

Anything else is noise.
posted by dirtynumbangelboy at 9:15 PM on January 9, 2008 [1 favorite]

Rule of thumb: A sniper always works in a team, never alone. A sniper will at minimum work with at least one spotter who monitors the target area through binoculars or a spotter scope at a lower magnification than the scope on the sniper rifle.

A two man team is, by definition, a conspiracy. There are no lone gunmen.
posted by Pastabagel at 9:17 PM on January 9, 2008

Both of the blackjack ones are either flat out wrong (assume it's an 8) or incomplete (dealer's up card is a 5 - you should take cards if you have less that 12 and double with a 10 or 11 at minimum)

I'm not impressed by the poker ones, either. For a start, what form of poker? One of them says that 4/10 starting hands will contain a pair, which sure as heck doesn't describe hold 'em. Others talk about making $x profit then walking away from a game - which is the exact opposite of the advice given by Doyle Brunson.

Good idea for a site, but the actual advice doesn't appear very good.
posted by Infinite Jest at 9:54 PM on January 9, 2008

It's like askme but less helpful because nobody asked.
posted by Slap Factory at 9:57 PM on January 9, 2008

Great idea for a new MeFi site: Don'tAskMe.
posted by The Deej at 10:44 PM on January 9, 2008

*scratches head* Hmmm. I thought this was a MeFite's site, but I can't find a Projects announcement... I'm sure remember someone announcing it at one of the places I hang out, though. Either way: neato.
posted by stavrosthewonderchicken at 1:04 AM on January 10, 2008

Different people submit the rules, it should be pointed out; if you disagree with one, it has little bearing on the validity of another.

Which is precisely what makes it less than useful.


I did read the link, or as much as I needed to, yesterday morning.
posted by Kirth Gerson at 4:28 AM on January 10, 2008

I've got a bunch of the Rules of Thumb books. They make for interesting reading, but not something I'd put too much stock in.

Also, I remember hearing the bike sizing rule when I was a kid. So it's a good rule - for old style large bike frames. Nowadays, frames are much smaller.
posted by ObscureReferenceMan at 8:18 AM on January 10, 2008

Connor: [during job training for Rosengurtie Baumgartener, an avid feminist] The rule of thumb here is...

Rosengurtie: Wait, rule of thumb? In the early 1900s it was legal for men to beat their wives, as long as they used a stick no wider than their thumb.

Connor: Well, can't do much damage with that then, can we? Perhaps it should have been a rule of wrist?

-- Boondock Saints
posted by quin at 8:32 AM on January 10, 2008 [1 favorite]

I have no idea why people are holding this site to such high standards. A rule of thumb is by definition not specific, but general; there are a lot of situations where it won't help, and a lot more where it will.
posted by tehloki at 11:06 AM on January 10, 2008

Well, the thing is, determining which situations it will or won't be helpful in isn't trivial. You need some way to determine that.

Accordingly, I've just registered rulesofthumbsforrulesofthumbs.com.
posted by cortex at 11:11 AM on January 10, 2008

I read the books they published years ago. Sure not every rule of thumb is consistent with your experience or your knowledge or opinion, but there are so really helpful nuggets in there if you read. I like the idea.
posted by JohnnyGunn at 3:10 PM on January 10, 2008

I'm in the middle of Gut Feelings right now, a good book on the topic of intuition and rules of thumb.
posted by carsonb at 8:48 AM on January 11, 2008