Yup, it is called garbage in, garbage out.
A "study" uses asking prices that are wildly all over the place to base a hypothesis and the results will be wildly inaccurate as well. <snip>
Autolist's data is not "all over the place" -- the chart below shows a very consistent pattern not just for Model S but for the ICE vehicles studied: "
Autolist’s data showed that at no point in the depreciation curve of any of these vehicles did a gas-powered rival have a stronger resale value than the Tesla Model S." This is clearly not some random effect as your comment suggests.
Also -- contrary to your suggestion that all cars in the class have a 3 year depreciation of 50-55%, autolist's data shows significant differences between the ICE models, ranging from 33 to 47 percent. They report wide variability in depreciation among ICE models (which is typical):
"Based on vehicle listings from January 1, 2012, through November 5, 2018, on Autolist.com, the value of a Model S with 50,000 miles on it had declined on average 27 percent from its original list price. A comparable Mercedes S Class -- the next closest competitor in the large luxury sedan segment -- had lost an average of 33 percent of its original list price after accumulating 50,000 miles.
The competitor with the greatest depreciation was Jaguar’s XJ, which lost an average of 45 percent of its listing value after 50,000 miles. Also included in the Model S’ segment are the BMW 7 Series, Audi A8, Porsche Panamera and Lexus LS.
The fact that the study is made based on autolist's listings doesn't invalidate the comparison between Model S/X and their competitors. There is no reason to believe that Tesla owners artificially inflate used car list prices compared to ICE competitors, much less do it consistently, year after year. In fact that seems totally implausible.
It is a fair critique that the list price may not reflect the final price sold, but that should affect all brands equally so would not change the conclusion that Model S/X consistently depreciate significantly less than their competitors. This lowers the overall cost of ownership which is good news.
It is the best, most systematic study I've seen on comparative depreciation between Model S/X and competitors. If you can point to a better one I'm all ears.