Beating the Checkout Blues
http://www.cooper.com/newsletters/2001_06/beating_the_checkout_blues.htm

Greenwood, Wayne
Cooper Interaction Design
2001

Abstract:

Depending on which research report you read, roughly 25% to 75% of online shoppers abandon their shopping carts before consummating the deal. Despite the disparity in numbers, all the research firms agree on one thing: that's way too many.