Arbitron has announced that the Media Rating Council (MRC) has accredited the radio average-quarter-hour monthly ratings data produced by the Portable People Meter ratings service in four additional markets: Chicago, San Francisco, San Diego and Charlotte-Gastonia-Rock Hill.

The MRC has also voted to continue accreditation in fourteen markets–Atlanta, Baltimore, Cincinnati, Houston, Kansas City, Los Angeles, Milwaukee-Racine, Minneapolis-St. Paul, Philadelphia, Phoenix, Riverside-San Bernardino, San Antonio, St. Louis, and Tampa-St. Petersburg-Clearwater. In total, 18 markets now display the MRC double checkmark logo for the radio average-quarter-hour monthly ratings data produced by the Portable People Meter radio ratings service. The MRC voted to not grant accreditation at this time in the remaining 30 PPM markets, and therefore PPM data in those markets continue to be unaccredited.

"MRC accreditation for our PPM markets is an important priority for Arbitron, and we are pleased the MRC continues to recognize the progress we are making," said Gregg Lindner, Arbitron EVP of Service Innovation and Chief Research Officer. "Continuous improvement in our PPM, diary and other information services is our objective, and we remain focused on our efforts to maintain the MRC double checkmarks in our currently accredited PPM markets and to achieve service-wide accreditation for all PPM markets."