The wonderful world of creating more from less

Effectively modelling multiple week campaign reach with fragmented diary panel data

Bas de Vos
Camiel Camps
Intomart BV


Since the mid 1980s the Dutch radio market has been rapidly growing. Advertising expenditures in radio have also been growing since this period. With increasing revenues a clearly growing professionalism can be observed. Along with more professional ways of selling radio airtime comes a heavier use of radio research data. It is increasingly necessary to use hard facts and figures in this competitive market. Competition between radio, sales and houses as well as competition with other media (e.g. television) forces us to do better in research.

The Dutch radio research by Intomart is one of the world's most comprehensive continuous radio studies. The research has been set up as follows:

  • One-week diaries to enable respondents to indicate listening behaviour per quarter of an hour.
  • Respondents are recruited to participate for one year, in which they receive a diary every two months. Respondents receive a maximum of six diaries during their participation.
  • Until 1999 the entire panel was recruited at once. Starting in 2000, recruitment is continuous: every month 1/12th of the panel is replaced by new respondents.
  • Panel size: 15,000 respondents plus 1,100 regional oversampling
  • Respondent data are free in use for media buying agencies and sales houses since January 2001.