Suppose a researcher selects a random sample of 100 men, measures their height, and constructs a histogram for the data.
Now if the sample size increases to a 1000 men, the histogram changes slightly—it becomes more balanced.
If the same size increases to 100,000 it levels even more.
If it were possible to measure the heights of all adult males in the world, the histogram would create something called the bell curve, or the Gaussian distribution.
This distribution is helpful for figuring out average weight and height distributions, intelligence scores, SAT scores, prices paid for new cars, the life span of light bulbs, the probability of flipping a fair coin—yet somehow it does not apply to Book Reviews. I think it should.
For a Gaussian curve, there is a rule for Standard Deviation.
- Approximately 68% of all the data items fall within one standard deviation within the mean (average) in both directions.
- Approximately 95% of the data items fall within 2 standard deviations of the mean.
- Approximately 99.7% of the data items fall within 3 standard deviations of the mean.
Applying the GoodReads rating system, this is fair:
1- didn’t like it
2- it was okay
3- liked it
4- really liked it
5- it was amazing
If book reviews followed the Gaussian curve, 68% of the books people read should be “liked it” they should be the average, the norm. Between the 95 and 68 marks, there’s 27%. One out of four books should either be really liked it, or it was okay. What’s left after 95%? 5 percent split between didn’t like it and it was amazing, so 2.5% of books for 1 stars, and 2.5 for 5 stars.
These are the books you would loan a friend your copy just to make sure they read it. These books are so amazing you’d give them away as gifts. A book this amazing you went out and bought at B&N full price after checking it out at the library.
One star books-These are books that you when you get to the ending you expect to see a printed page with a website leading you to an apology from the author. These are the books you pick up when you want to die a long slow horrible death.
“But all the books I read are amazing,” you say. And for someone reason, everyone seems to either really love a book, or they hate it. We end up with a skewed curve that looks something like this:
Sorry, but all books can’t be 5 or 4 stars. This is the problem Harvard has with it’s applicants. They’re all really smart and talented, but only X number of students can attend. What do they have to do then? Raise the bar, scrutinize even more. Think back and ask yourself, was that book really *that* awesome, or was it just really good? Maybe you really just liked it, but you didn’t want to hurt someone’s feelings and so you gave it a higher ranking that you really meant.
Luckily though,the whole Gaussian curve system ends up working out any way even if no one corrects their habit of only leave 1,4,and 5 star reviews. Because once all of the “Amazing” and “Didn’t Like It” ratings are averaged, the rating drops to the standard 3-point-something star review–and the Gaussian Curve triumphs again.