Miller’s Law – A Rule in Product Design and Life Management(blog.prototypr.io) |
Miller’s Law – A Rule in Product Design and Life Management(blog.prototypr.io) |
I’ve used the principle of Millers law to start asking people to measure on a scale of 1-7.
Universally, people balk at the scale. But I explain to them that most people can’t tell the difference between 2 and 3 on a ten point scale. If you can’t articulate a difference, there’s no use in the measurement.
Seven is great because you get more than the simplicity of 1-5. So... 1 - the worst 2 - bad 3 - below avg 4 - average 5 - above average 6 - good 7 - the best.
And don’t even THINK about responding with “5.5”. ;)
I work on modeling human sensory perception and preference of food and beverage products, and have had to design scales that work as a true "metric";
Most scales suffer from 3 primary problems:
1) avoidance of the endpoints
2) tendency towards the mean
3) minimum information gain
For example; on a 10 point scale, very few (> .5% of respondents) will mark a 1 or 10 (this is problem 1). In addition, 5's are over represented VS the expected amount of 4's and 6's (problem 2).
These problems together reduce the amount of information inferable from the collected data. There is a number of ways to measure this, including information theory (think of the avoidence of the end points and tendency towards the mean as a lossy compression algorithm for the true signal) or as a sampling of an unrepresentative population to infer the posterior distribution.
A 100 point scale has the same problems as above, and in addition suffers from a lack of consistency (reproducibility) - respondents are likely to give a product a different score (say a 92 and 94) when asked about the same product multiple times. This will frequently lead to non-parametric rank reversals, which 1) prove that a 100 point scale is not a "metric" and 2) show that the amount of information is further reduced at higher optionality.
Thus - the discrete scales that work best are:
A) 1 - 7
B) 1 - 13
as they both do not suffer from avoidance of the end points, both have no selectable mid-point (forcing respondents to choose a point above or below the median), and are highly replicable (very few respondents will switch rank orders).
Because science.
The 7 +/-2 rule is, in part, about the design and layout of information so as to better aid the end user in leveraging the way their memory stores information spatially.
In short, it's about how to best design a system to give information TO a user.
What you're talking about is pretty much the reasoning behind methods like 'Fist of Five', 'five star' or '5 face' voting systems. These are methods well grounded in psychology and I might argue going up to 7 is unnecessary.
I generally like my scales to be logarithmic. At work, I made the following scale to explain difficulty of technical items to non-technical people. It works quite well:
Effort Scale
1: Easy peasy
2: Trivial but time-consuming
3: Some invention required and non-trivial
4: Invention required
5: Lot of invention required
and for special occasions:
6: This is a whole new startup
However it seems that drivers who have an average of say "4.2", despite being perfectly fine and giving above and beyond service 1 in 5 times, gets kicked off. This means that 5 is acceptable and there's no way to mark above acceptable.
I'm odd, I don't expect every trip I get to be above average. That's clearly not possible.
Basically it uses an 11 point scale and your net promoter score is the proportion of 0-6 (negatives) subtracted from the positives (8 or 9-10). I may have got ranges wrong but the idea is the same. This was touted as "the only number you need to improve" for business success.
A cat was playing with a ball under the tree. An apple fell from tree on cats head. The cat squared around the apple and ran inside the house through a small door into her box. King dad drove in his car, took out huge hammer from the trunk and hit the box of milk. Milk sprayed all over the house and inside the fish tank. Fish got restless and caused a cross bow from the wall to fire an arrow through the book that was all taped over. Mom in her red shoes came and took the key under the flower.
The CAT looked at me eating an APPLE, I threw a BALL outside to see if it would chase it instead it climbed a TREE...
The couple key strategies for a memory palace are:
1. Ensure your palace is as real as possible. Spend some time mentally mapping out every detail of your palace in your mind so that you don't have to later.
2. The more animated or "human" the better. Our minds are better at remembering faces.
3. The dirtier the better. Our brains are also way better at remembering sexual imagery.
I got about 13 words on this test using this technique poorly and it only took a couple seconds (and I didn't memorize the second half of the list).
For example, for the words "king" and "hammer", I imagined a king hammer ruling over his subjects. For "milk" and "fish", I imagined a fish with udders. They're silly, but they work.
More and more I believe that ignorance thus space exploration and Miller's "level 1" cache has a huge role in our enjoyment of things.
On a more relevant note, it's easier to remember a large number of things when they're related to each other in meaningful ways. So the results of this little memory test aren't very good predictors of your ability to remember things in a real-world setting.
The skinny cat with an apple on it's head ran after the ball that led it to the tree with square leaves. Each leaf was actually a picture and if you looked closer you could see a head (of a fat cat) in the picture. You zoom in and the picture becomes a movie and you see the fat cat walk up to a house and open the door... etc etc
The more absurd the image you create the easier it is to remember. You also have much better long term memory. It's been half an hour since I memorized the list and I've drawn my attention to 5 other HN posts, but here I am able to recite the list 100% accurately and without hesistation...
Cat apple ball tree square head house door box car king hammer milk fish book tape arrow flowers key shoe
This is nothing against Miller's Law though... as who goes about creating visual stories to memorize user interfaces :)
That would be a much better goal for product design. You don't want designers to pack things by 7 or 9. It's too many.
https://en.wikipedia.org/wiki/Method_of_loci
https://www.ted.com/talks/joshua_foer_feats_of_memory_anyone...
Not that anyone remembers phone numbers nowadays.
The comment below mine, about "bit" being used as "piece", was my first thought too. But then the author contrasts with a quote using the actual entropy definition of a bit.
And chunking doesn't work as an explanation either, even with Huffman encoding, unless half of all words you ever use are "cat".
Note that even if the word was used incorrectly, it makes no difference on the author's argument.
If the menus and options were grouped in way that is in line with human psychology, it would be easier for novice users to find that one option. I know the Office ribbon gets flack on HN but Miller's Law is one of the big reasons for the Office ribbon and how it is designed which makes it a lot easier for novice and intermediate users to find that one option in Office.
But in an Uber, giving less than a perfect score can get someone fired. So it's 5 stars unless the driver literally spits on me, and then it might be 5 stars and a complaint. Anything lower than a 5 star rating feels unethical, like stiffing a waiter on a tip.
What I can't figure out is how this is of any use to Uber. They have created a "metric" where a large chunk of their customers regard answering honestly as a social faux pas, at best, so what do they think they're measuring?
I think a simple thumbs up/thumbs down would be just as effective.
I only gave out one 3 star, but that was because the driver was very bad, though not taxi-driver bad, which is what I would consider 1-star.
When I was at school in the UK getting an A meant you where really good and a triple A at A level was super rare and less than you would need to get into Oxbridge
Forcing individuals to choose a score above or below the mean yields a better sampling of the true distribution in this case.