"It (Common Entrance Test) will take three to four years for being introduced in all states," he said at a media interaction here.
Sibal said that during his talk with West Bengal Chief Minister Mamata Banerjee during the day he was assured that the state would join CET in 2014.
CET, he said, would help reduce multiplicity of examinations and the number of coaching institutions.
Sibal said he has information that the turnover in the coaching institution business was between Rs 15,000 and Rs 20,000 crore.
"This can reduced if a child is tested by an educational institution only on what he has been taught," he said.
CET is also aimed at wiping out the practise of taking capitation fee by some private institutes as the test results would apply to both government and private colleges, he added.