LEGO Price Estimates Over Time

LEGO recently introduced a new LEGO set called Research Institute which featured three female scientists. Since my wife is also a female scientist, I tried to order one from the LEGO website only to learn that they had sold out in less than a day. I then wrote an email complaining about this to LEGO who responded by sending me an apology note and a catalog.

I grew up playing with LEGO sets, hard to avoid when you were named Zach and commercials like this dominated the airwaves. Anyways, when I was a kid my dad once mentioned to me that a good rule of thumb for determining the price of a LEGO set was to estimate each brick costing about 10 cents. This new catalog made me wonder if this was still true. I copied all the model numbers as well as the number of pieces and the prices. I was also curious in how true this trend was when adjusted for inflation so I used the CPI Inflation calculator from US Bureau of Labor Statistics which showed that $0.10 in 1989 had the same buying power as $0.19 in 2014. Ideally I could have found a catalog from 1989 but I don’t remember any back then and I probably would have cut it up to put pictures in my locker or something like that. I used R to plot both of these trends and it appears that my dad’s estimate still holds true for 2014.

A correlation calculation for all sets gives a value of 0.91 which means my dad had a pretty good estimate back in the day.

I also looked at the average price for each collection and found that almost all collections retained a high correlation between the estimated price and the actual price.

Collection Collection Mean Price Collection Correlation
Basics 29.99 NA
Chima 38.99 0.977
City 54.365 0.896
Creator 100.375 0.955
DC Superheroes 76.657 1
Disney Princess 27.657 0.963
Exclusive 149.99 NA
Friends 23.354 0.992
Ideas 49.99 NA
Juniors 27.49 0.901
LEGO Movie 63.99 0.997
Marvel Superheroes 40.99 0.934
Mindstorms 349.99 NA
Minecraft 139.96 NA
Mixels 4.99 NA
Ninjago 47.434 0.976
Simpsons 199.99 NA
Star Wars 133.365 0.979
Technic 81.99 0.989
Ultra Agents 45.323 0.983

Raw data and code for this lives at this gist

lego, r,