THE Housing Authority is to review regularly the market supply and demand for medical services, said the Secretary for Planning, Environment and Lands, Tony Eason. He told legislator Dr Conrad Lam Kui-shing that the authority had considered allowing demand and supply to regulate the clinic-to-population ratio, but rejected the idea for fear of raising the costs of providing medical services. He sidestepped a question from Dr Lam on why the introduction of market forces would drive costs higher. The authority reviewed the situation late last year. The ratio was one clinic to a population of 7,500 to 10,000 people, Mr Eason added. He told members that improvements to the balloting system, which served to allocate new and vacant premises to applicant doctors, and stricter tenancy controls over the operation of the clinics had attracted little feedback.