After years of deliberations that stretch back well into the Arbitron years, Nielsen has made a major change in the way it gathers and reports data in diary markets. Markets that are measured twice or four times a year will go to year-round measurement and monthly reporting. What is known as Continuous Diary Measurement will roll out in phases, beginning in July 2019. The four-book markets will change over first, followed by the two-book survey areas. Even in the very smallest rated markets, ultimately the ratings company will provide monthly reports consisting of rolling averages of the preceding 12 months; in the larger diary markets, each monthly report will cover the preceding six months. According to Nielsen, with the first conversion phase they will be reporting approximately 70% of radio’s ad spend.