Edexcel exam board's diploma in digital applications has divided opinion since it was introduced two years ago. Critics have found fault with its assessment model. However, the board said 200,000 students were registered to take it by this summer.
The course was originally billed as a natural replacement for the popular GNVQ in IT, until the OCR board launched a rival National Certificate in IT last summer.
Gary Clawson, the chief executive of North West Learning Grid, a consortium of local authorities which provides resources for both courses, said that in the past month some 700 schools which had been offering the diploma had registered for OCR Nationals teaching resources. He believed that most of these would soon switch to OCR's course.
Mr Clawson said many teachers were still unsure what pupils needed to do to pass the diploma and that its electronic assessment system was problematic.
OCR is assessed through paper-based coursework, which made it simpler, Mr Clawson said.
An Edexcel spokeswoman said: "Two hundred thousand students are registered for DiDA for the summer 2007 series. Our teachers have worked extremely hard to achieve such attainment and have been determined not to compromise the quality of education for their students."