Analyzing the spam test results

Digging deeper into the accuracy and performance data

Back to index: Spam in the Wild, The Sequel

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Back to index: Spam in the Wild, The Sequel

False positives: The best scores in our test all reflect products that have gotten the science of not tagging legitimate mail as spam down to the noise level. Any false positive is a problem, and non-delivery receipts (NDR) and mailing lists caused the most problems for the anti-spam products. Many mailing lists might be unimportant, but some are critical. The same is true for NDRs. If you send a mail and it doesn’t go through, your only clue is the NDR coming back from your own mail system or, sometimes, the other end. Anti-spam packages that filter these out a little too zealously (because they assume that most NDR messages are the result of a mass-mailing worm), which we found in many of the products we tested, break that feedback loop and make mail less reliable.

In last year’s test, false-positive rates were much higher, and we said a quarantine was a critical requirement. This year, while the false-positive rate has dropped overall, we still think that most businesses using e-mail as a critical communications tool need some way to deal with false positives.