Almost half of email marketing campaigns are not adequately tracked to gauge their return on investment (ROI), according to a new report.

The Email Marketing Industry Census 2007 from Adestra shows that 47 per cent of commercial managers are not assessing increases in revenue following electronic mail programmes.

This is in spite of the fact that email marketing is the second-largest outlay for the average company after website costs.

Paul Crabtree, marketing director at Adestra, said: "It is critical for future growth and makes basic business sense to be able to measure ROI."

"The point is that email marketing is probably the most direct channel to be able to measure ROI," he added.

Mr Crabtree advised that enabling ROI tracking for email promotions can be a relatively simple process.

Of those companies which do measure returns, 55 per cent said email methods yield a three-times ROI, while the figure rises to five-times in 32 per cent of cases.

Industry researcher E-consultancy, which collaborated on the census, suggests that mobile platforms and online syndication may be effective complementary techniques to email campaigns.