Platforms that detect when sensitive corporate data is leaked are more effective against people making honest errors than they are against criminals trying to steal the data, according to one analyst.

A small percentage of data that leaks from corporate networks (0.5%) is stolen by professionals whose efforts will evade detection by security products touted as data-leakage prevention tools, says Nick Selby, an analyst with 451 Group who spoke at the Security Standard conference Monday.

The products do catch data leaks, 98% of which are linked to an accident or stupidity and 1.5% that are caused by vengeful employees clumsily attempting to steal data, he said.

"Data leakage is an anti-stupidity issue as much as it is a technology issue," Selby says. "Most data-leakage products can't discover activity by skilled insiders looking to steal."

He says the products should be recast as tools that can help eliminate data breaches made in error, rather than those that are done intentionally.

Selby named Reonnex, Vontu, Onigma (bought by McAfee), Tablus (bought by EMC/RSA) and Port Authoritiy (bought by WebSense) among many others. He singled out these vendors because they have been the recipients of venture-capital dollars. He says the total investment in this technology amounted to $250m (£125m). "That's an awful lot of money," Selby said, "and vendors, you're not going to fix [the problem]."

The problem of keeping corporate data safe was complicated, he said, because most businesses don't have any idea where all their data is, much less have it classified as sensitive or not. Leakage products can be useful because they crawl network databases, locating and categorising data.

To accurately detect abuse, these products need to track behaviors of users. "It needs context. What did they do, why and have they done it before?" Selby says. If a device cannot determine whether access to certain data represents a threat, it should note that.

Selby said that within 19 months data-leakage technology would be blended in with other products that scan network traffic. He advised customers of such products to buy from vendors that offered more than just data-leakage products so they were more likely to be in business in a year or two when they needed support.