Rarely is performance the only factor in a purchase, though. One must never forget that it's just as important to be able to do the job correctly as it is to do it quickly. Any aspect of computer performance that matters to the user can be benchmarked. There are many factors involved in correctly understanding and interpreting benchmark results, whether they come from your own locally generated test or are supplied by the vendor of a commercial system. You'll need the name, version, and details on any changes made, whether for portability or to improve performance.
Benchmark numbers come from mathematical formulas, many of which involve averages.
Some benchmark tests produce a score that is relative to the score of a base machine. The harmonic average is appropriate here because the benchmark deals in both transactions and seconds. These tests combine to form transactions, which in turn combine to form mixes and mixes form an object, called a test suite. Each transaction produces a score in transactions per second, and ServerBench combines these rates using a harmonic average to produce the overall benchmark score for that server. This number reflects the total number of transactions the server executed and the total number of seconds it needed to run the entire mix.