While Arbitron scrambles to fix PPM without spending more money than necessary, it is also trying to address issues with the diary methodology without spending more money than necessary. It has announced that beginning with the Spring book, households will have a second chance to participate. According to Arbitron's Pierre Bouvard as quoted in Inside Radio:
They'll use it if a household doesn't return any diaries, giving them a "second chance" to take part in the survey. If it works, it would help improve the response rates.
Only in the Orwellian world in which Arbitron lives could this be sold as a means to increase response rates. It costs considerably more to recruit a new household than it does to go back to a household Arbitron has already recruited. If the company can convince them to try again, Arbitron saves money.
The problem is that Arbitron's own research shows that non-respondents listen to less radio than those who fill out diaries. By going back to households who have already refused, Arbitron increases the proportion of light radio users. It practically guarantees that average listening levels will drop as a result.