Nielsen versus Arbitron: Why It Matters to Radio: "How the study was conducted
Our clients provided the contact information for nearly 100 key radio media buyers. The media buyers were those who regularly buy radio, so the views expressed were from the perspective of the radio time buying community, and presumably would favor Arbitron. By telephone Harker Research interviewers contacted as many of these buyers as possible during the week of December 1st. We ultimately completed interviews with 62. This is a significant proportion of the universe of media buyers, so the results are a reliable representation of the views of all radio oriented media buyers.
We first confirmed that the participant bought radio time and then proceeded to ask the four questions. For each comparison question they could choose either Arbitron or Nielsen as a response, but we also accepted 'don’t know' or 'both.' That is why the two responses do not add to 100%.
(Via Radio InSights.)
One point made in their article was that there hadn't been much made of cross-media measurement with PPM. Here's the quote:
"While Arbitron has touted PPM as a means to measure any audio based medium, there has been very little said by the company about actually measuring any medium other than radio (except in special commissioned projects). This is one area where Nielsen is clearly ahead of Arbitron. If Nielsen follows through with its promises, small markets may have a new tool to compete against other media. Let’s hope that Arbitron responds by providing the same information (at no charge) in larger markets."
Arbitron actually conducted some very in-depth research into the multi-media aspects of PPM, with live data being made available during both the Houston and Philadelphia test periods. In fact, the MRC accredited the data in Houston just over a year ago. Here's a link to the RBR article about that: Arbitron gets MRC Blessing for PPM TV data
The competition between Arbitron and Nielsen will only make both services get better - and that bodes well for both sellers an buyers of tv and radio advertising.