Students would get the opportunity to take exams whenever they were ready, transferring control of the exam system away from administrators.
In an essay published today, Martin Ripley and Sue Walton of the Qualifications and Curriculum Authority examine the case for "when ready" testing.
The idea builds on government plans, published last week, to give students the chance to vary the pace of their learning from 14 to 19.
It goes further, however. The Government's plans could be achieved simply by allowing students the chance to, say, take a GCSE a year early.
"When ready" testing would allow students to take an exam when they had finished a module of work, or on a choice of dates throughout the year, or through logging on for a computer test.
Students could then progress at their own pace. The tests could be used to identify weaknesses if resits were allowed. They could also reduce demands on examiners by spreading exams throughout the year.
However, pupils might get lower results if they took the test earlier, cheating might be easier, and it could create administrative difficulties in schools.
The QCA described the paper as "blue skies thinking". But QCA chief executive Ken Boston said that it would influence the future of assessment policy.
"Whither Assessment?", pound;12 plus pamp;p from QCA publications, PO Box 99, Sudbury, Suffolk CO10 2SN, tel 01787 884444, www.qcashop.org.uk