what idiot did the math on this article?
Had to laugh at the quote. This is very typical of misunderstood engineering math. But the number in the article is correct. The trick wording is "annual failure rate" and how you calculate that. In reliability statistics, this is called FIT rate.
The drive population in the study is 172K unit, but the population ** age** is much older than 12 months. The average HDD age in the study is 49.63 months but the average SSD age is only 12.7 months. They are calculating FIT rate (failures in time). By using their numbers, I calculated a slightly larger FIT than they did. With FIT rate, you can also approximate MTBF (mean time between failures).
Another note: Having spent a large portion of my career working with reliability, I always find it interesting that we miss the entire picture with "study bias". In this case, the design and failure modes are not being checked for any other possible differences that also are effecting the numbers. If most of these SSD were actually SATA and SAS type SSDs, those also have the nice feature that they are totally enclosed so the user does not touch the PCB.
In other words, the risk of ESD damage is much lower (static discharge).
Due to legacy HDD design structure and no industry interest to address the failure modes due to packaging, almost all rotating HDDs have their control PCB exposed. So the user / installer can inadvertanly touch it. ESD damage is VERY pervasive in the electronic industry and is considered the highest single failure mode other than user error.
If they parse the data into which SSDs are enclosed SATA/SAS versus open PCB M.2 types, they might actually see somthing very interesting. I would bet money that the M.2 SSD have a higher annual failure rate than SATA type SSDs.