Ratings distribution chart

You can see it on each set page.
(Here's an example.)

The ratings distribution chart tells us how the LEGO community generally score sets. This is useful since all communities have their own distribution. The movie community is generally pretty critical, making a score between 75-85 pretty good.

As you can see, the LEGO Community seem to think pretty highly of LEGO sets in general, making a score of 75-85 pretty average.

I see. But what about the colors?

When we know the average score and the number of sets, we can calculate something called the standard deviation. This number tells us how many points there are between each score on average. It's currently 8.92. We use this number and say that if a set is within one standard deviation from the average it's an average score. Anything below that is bad, and anything above is good. We represent this with three colors:

• Green is good. That's 88.03 or above.
• Yellow is average. That's between 70.19 and 88.03.
• Red is bad. We're at 70.19 and below here.

Does it seem like a set needs a very high score to be in the green? Does it feel unfair? It's just a byproduct of the general scoring we use, but it certainly enables us to consider: why is that? Does LEGO produce really fantastic sets? Or are we, ahem, rabid fanbois? Regardless - by using the average score and standard deviation we know which sets are truly awesome.

Oh, and to make it even more fun, we can do the same calculation for all sets released in a certain year. You can see the result of that on every set page as well.

The chart used here on Brick Insights is divided by steps of four, giving 25 steps in total. That's a totally arbitrary decision, but I felt it was a good number. It's evenly divisible by 100 and has enough detail to be useful.

I'm not a statistician, but this was a lot of fun to learn. Here's a good article on how to calculate the standard deviation. We're calculating on population, not sample.