Weeks before it was supposed to go on-line in some of the nation’s largest radio markets, Arbitron has decided to delay the roll-out of its personal people meter (PPM) system.

In a release, Aribtron’s chief exec and president said:

… over the past three weeks, feedback from our customers, the Media Rating Council and other constituencies has led us to conclude that the radio industry would be better served if we were to delay further commercialization of the PPM in order to address their issues.

Chicago was supposed to make the switch to PPMs starting in March, but the market will now be delayed until September. The city joins several other markets, including New York, San Francisco, and Dallas, who will all be waiting until later than expected to use the new technology. In the meantime, these markets will remain on the diary system.

Clearly, this is a major stumble for Arbitron. They have been touting the accuracy of this new technology for years and have been ramping up their promotion of PPMs in recent months to both advertisers and radio stations.

With this delay, the hope is that Arbitron will figure out better methods for recruiting panelists to carry the PPMs. There have been major concerns from various watchdog groups that certain demographic segments — including ethnic minorities and adults under the age of 35 — would be underrepresented by the new technology. Arbitron has yet to answer those objections.

Shares of Arbitron stick dipped precipitously on news of the delay.