Between the insurance-speak and auction-ese, we admit we can get a bit wonky at times. Here's a guide to some of the terms we use.


Changes to an insurance policy. For our purposes, the changes include increasing or decreasing the agreed value of a vehicle or adding (buying) or removing (selling) a vehicle from a policy. In aggregate, those endorsements provide an excellent look at what’s happening in the market outside the auction tent.

Year-over-Year changes (or year to year)

Stats from one period in one year compared to the same period in a different year. Example: The average temperature in January 2018 was 32 degrees, and the average temperature in January 2019 was 35.2 degrees. The year-over-year change in the average temperature in January from 2018 to 2019 was a 10-percent increase.

Red Book

Certification Ferrari issues to cars that pass rigorous inspection (and, in some cases, in-house restoration) and match original build records.


A measure of the likelihood that the sample is the result of a random outcome. A smaller value indicates that it is unlikely to be random. These are helpful for us as we look at data from limited sample sizes. For instance, we talk about Pre-Boomers being the biggest audience for $10m+ cars in 2018 (see page XX). The sample size was only a handful of sales, but the p-value is 0.04168251, which is less than a five percent significance level test, and a sign that the sample is reliable.

Hagerty Insurance Quote Data

Details Hagerty agents collect when someone calls for pricing on an insurance policy. Includes information on the car (e.g., model year, stock or modified) and personal/household details (such as whether there’s a 16-year-old living at home). The Valuation Team uses the quotes (aggregated and stripped of identifying details) to track market trends.


A numerical rating of the physical presentation of a car, on a scale of 1 to 6, as it is observed in a walk-around. Condition doesn’t attempt to differentiate between totally original cars, street rods, and race-modified cars.

#1 condition Beyond perfect. While logic would equate this with a factory-fresh car, the collector car world hasn’t adopted that way of thinking, creating Pebble Beach, Louis Vuitton, and other restorations that are better than original.

#2 condition Showroom-quality. Virtually new.

#3 condition Normally used, low-mile cars that have been kept original, or restorations that have seen some miles but have been well maintained. You would put a 3 in your garage and drive it on weekends without feeling embarrassed or endangered in doing so. Most collector cars are 3s.

#4 condition Serious defects, and/or hard use not ameliorated by good and consistent maintenance. You wouldn’t take a 4 to a local marque rally without being a bit self-conscious. Nevertheless, many daily drivers are 4s.

#5 condition Running, but battered, incomplete, and perhaps rusty.

#6 condition Parts car.

Character: Qualitative descriptions of cars’ overall character, such as “Older restoration.” They attempt to describe, in a limited number of phrases, the kind of treatment the car has received. There’s a vast difference between cars described as an “Unrestored original, #3 condition” and an “Older restored #3 condition.”


At the dawn of the automotive era, dynamometers capable of measuring actual horsepower were rare. Engines were simple and uniformly inefficient, so rather than measurement, a standard formula was developed to assess taxes and provide comparable power ratings for automobiles.

In Great Britain it was overseen by the Royal Automobile Club (“RAC hp”), in France by the government (“CV” or cheval vapeur), and in the U.S. by the Selden patent organization, the Association of Licensed Automobile Manufacturers (ALAM). After Henry Ford broke the Selden patent, U.S.
ratings were done by the National Automobile Chamber of Commerce.
RAC and ALAM used the same formula which, curiously, doesn’t take into
account the engine’s stroke. It’s thus displacement independent. The formula:


In the case of the Simplex Speed Car (inset above, see page 48) with 5.375-inchbore and four cylinders, it is:

28.9 [5.3752] X 4 [CYLINDERS] X 0.4 = 46.2 ALAM HP

This was pretty accurate in early single-cylinder and V-twin engines, but soonbecame only an approximation. Today, it’s not even close enough for handgrenades. A Chevy LS7 (505 hp) has an ALAM hp rating of 54.45 hp.