Out of the Lab and into the Field: A Pilot Test of the Personal Portable Meter (PPM)
测试了一种能检测音频媒体暴露的个人便携式测量仪（PPM），在英国试点中50名受访者佩戴9周，结果显示编码解码系统有效，受访者合作度高，为后续大规模测试奠定基础。
Since 1992 Arbitron has been developing and testing a personal portable meter (PPM) system capable of detecting exposure to any audio medium, both in-home and out-of-home. With this system, an inaudible identification code is embedded into the audio signal of radio, television, cable, and other media outlets. These codes are then detected by pager-sized personal meters worn by respondents. The 1998 pilot in the United Kingdom was the first fully functional test of the entire PPM system. Fourteen radio and television stations encoded their signals and we recruited fifty respondents to wear the personal meters for the nine-week test period. Results showed that the encoding and decoding systems functioned as planned and respondent cooperation levels were high. All encoded stations were detected by the meters and respondents wore or carried the meters for a median 14 hours per day. Given these positive findings, we are proceeding with a larger scale PPM test panel in the United Kingdom which started in June 1999.