George Ivie, executive director of the MRC – the body tasked with auditing ratings services in the US – wrote in a letter: “Our process is sound and we believe that any attempt to replicate our industry representation and expertise by a government entity would be difficult if not impossible.”

Ivie’s comments were made as part of the FCC’s “open and neutral” inquiry into radio ratings firm Arbitron’s new portable people meter-based (PPM) measurement system, which is replacing the traditional paper diary-based method of logging radio listening habits but has been accused of under-representing ethnic minority audiences and thus harming the ratings of stations targeting certain ethnic groups.

Arbitron has also been criticised for failing to get the MRC’s ‘seal of approval’ for its PPM-based measurement services before launching them, but the company has said it is committed to eventually securing accreditation in all PPM markets.

Earlier this week it was revealed that a Congressional committee has decided to pursue its own investigation into the impact the introduction of PPM is having.

But in his letter to the FCC, Ivie said: “The MRC has strived for four decades to be faithful to the mission that Congress defined for it. Congress originally reached the conclusion back in the 1960s that industry self-regulation of rating services was preferable to government regulation and we believe this conclusion remains relevant and appropriate today.”