The automotive blogs are all picking up Dan Lienert’s Forbes piece on “Value-Losing Cars,” a list of the cars that depreciate most quickly according to multiple sources. What all of them, including Mr. Lienert, fail to note is that these depreciation figures, like nearly all I’ve ever seen, are misleading.

In the article and elsewhere, depreciation is calculated by dividing a car’s current value by its orginal MSRP, the reail price recommended by the manufacturer. When calculated as a percentage of MSRP, resales values mislead at least as much as they inform. While domestics do seem to depreciate more quickly, they do not depreciate nearly as quickly as these figures suggest for two simple reasons: rebates and discounts.

The Durango, for example, can often be bought for $8,000 or more below MSRP once rebates and dealer discounts are totaled up. A base Durango that lists for $27,025 is currently being advertised for about $19,000 (based on MotorAlley’s “Best Deals”). Using the 23 percent resale value from the article, we can figure that this Durango is projected to be worth $6,216 after five years. Well, as a percentage of the transaction price it’s actually 33 percent. Still not good, but not nearly as bad as 23 percent.

Sadly, this is a downfall of pretty much every depreciation figure I’ve seen. Given the size of the incentives and discounts available on many models these days, it’s time for the companies that provide depreciation information to stop basing their calculations on MSRP.