Benchmarks

Date: 03/25/2001 at 13:39:09
From: Rita Mazina
Subject: Benchmarks

What exactly is a benchmark? Could you please show an example?

Thank you!

Date: 03/26/2001 at 15:03:55
From: Doctor TWE
Subject: Re: Benchmarks

Hi Rita - thanks for writing to Dr. Math.

A benchmark is a way of comparing two or more things numerically. For 
example, to compare how efficiently different models of cars use 
gasoline, the Environmental Protection Agency runs the cars on a test 
track under controlled conditions, and measures their fuel efficiency. 
These numbers are called "benchmarks."

A Mazda Protege, for example, might be EPA-rated at 30 mpg (miles per 
gallon) city / 38 mpg highway. A Ford Taurus, on the other hand, might 
be rated at 22 mpg city / 36 mpg city. What this means is that the 
Protege got much better gas mileage when they simulated city driving 
conditions (30 mpg vs. 22 mpg), but only slightly better gas mileage 
when highway driving conditions were simulated (38 mpg vs. 36 mpg).

These numbers are for comparisons. If I was going to buy a new car and 
wanted one that would get good gas mileage, I'd look at these EPA 
numbers to see which was better. I'd also have to consider how much of 
my driving is city driving and how much is highway driving. Once I 
bought the car, how many miles I got per gallon of gas would depend on 
my driving habits, the weather, whether I kept the car in good repair, 
etc. That's why they always say, "your actual mileage may vary" at the 
end of the commercials.

Sometimes (but not always) benchmarks have a "standard" against which 
other numbers are compared. For example, to compare the processing 
power of various models of personal computers, PC Magazine will run a 
set of test software on one particular type of machine. The resulting 
performance will be assigned a "benchmark" rating of 100, and all 
other machines tested will be compared to that standard. So a machine 
that gets a benchmark of 133 is 33% better (more powerful, faster, 
etc.) than the standard, while a machine that gets a benchmark of 80 
is 20% worse than the standard. Of course, how well a machine performs 
for you depends on what software you're running on it. Again, "your 
performance may vary."

Benchmarks aren't limited to cars and computers. Many institutions use 
benchmarks to evaluate everything from jet engines to stocks and 
bonds. In fact, any time you use a standardized testing environment to 
compare two or more things, you are using a benchmark.

I hope this helps. If you have any more questions, write back.

- Doctor TWE, The Math Forum
  http://mathforum.org/dr.math/