A spokeswoman for the Government agency said the review was part of a regular, three-to-five-yearly review.
Nine agencies, including Millward Brown Precis, are on the current roster.
The agency is understood to be looking to remain on the roster.
Last year the COI carried out more than 15 media evaluation projects on behalf of government departments and agencies.
This has included work for the Department for Education and Skills and the University for Industry.
Projects in the past two months are estimated to be worth around £250,000.
Also under review is the COI's educational marketing roster, which has included promotional work to raise awareness of career opportunities within the Royal Air Force.
COI head of sponsorship and PR Oliver Hickson said: 'Evaluation is core to COI work and it can help to inform future PR campaigns.'