Spam filters: Users still fearful over false positives

Email users are keen to have unsolicited emails filtered out, but are undoing much of the labour-saving good work of their filters by then insisting on seeing all mails before they are deleted in order to check for false positives.

That is one finding of a recent SurfControl survey which also revealed a third of business email users are still very concerned about false positives - emails wrongly identified as spam - being blocked or deleted. Although high numbers of false positives should no longer occur with advanced filters it seems concerns still persist.

The survey revealed 15 per cent of businesses receive daily complaints from users about the number of false positives and 30 per cent of employees want to keep tighter control of their spam management.

Steve Purdham, CEO of SurfControl, told silicon.com: "I think what we're talking about here is perception - the perception that perhaps more things are getting lost than really are. Perhaps two years ago it may have been one in a hundred emails, now it's probably more like one in a thousand."

However, while much has been said about the cost of spam - in terms of resources, bandwidth and man-hours - it is almost impossible to quantify the cost of false positives.

As such, some individuals may consider even one in a thousand too short odds. While it could be a missed email from a friend who might follow up with a phone call it could also be an important sales lead, work offer or request which goes unanswered - potentially damaging the relationship with the sender.

Concerns about the potential costs of false positives may also slow down a move to managed services where much of the filtering takes place out-of-house.

However, Purdham said: "I think, if anything, the concerns seen in these findings are recognition of the fact a layered solution is the best solution. If something is definitely spam or definitely a virus then the best place to stop it is before it even reaches your network but where there is still any doubt users don't want to hand over control."

"These concerns may prove a stumbling block [to a move to managed services], but we're probably talking 12 months - and in technology terms that's nothing," added Purdham.