Station to Station
Total Page：16
File Type：pdf, Size：1020Kb
STATION TO STATION Measuring radio audiences with a PPM panel in Québec Pasquale (Pat) A. Pellegrini Ken Purdye The authors report findings from a comprehensive analysis of radio audience data captured by Arbitron’s Portable People Meter (PPM). The paper compares the diary and PPM results for a common area and time period and list of stations. Comparisons, not unexpectedly, show differences in overall amount of radio use, the distribution of radio use by time periods, the relative importance of radio listening for different subgroups of the population, the reach of radio, and shares and reach of the different stations. There are also indications that the structure of radio listening (e.g., relative weight of heavy-light listening, demographic profiles, etc.) is different. The reasons for these substantive differences are explored. It becomes evident that the tasks of writing a daily diary and carrying a PPM attract different populations, as measured by standard demographics, socio-economic and lifestyle variables, but account for relatively small differences between the methodologies. The paper also examines differences in the definition and measurement of radio listening as the reason for differences between diary and PPM measurement. This analysis points to the definition of radio listening as the predominant reason for the different radio audiences observed. © Copyright by ESOMAR® / The ARF 2 Pasquale (Pat) A. Pellegrini, Ken Purdye INTRODUCTION BBM has been operating a commercial Personal People Meter (PPM) panel for the measurement of French-speaking television audiences in Québec for almost two years now. Our extensive experience in setting up and enhancing this panel is covered fully in an earlier paper (Pellegrini and Purdye, 2004). In addition to measuring TV audiences, 22 radio stations (both English and French, Canadian and U.S.) have allowed their signals to be encoded to facilitate the testing of Radio measurement by this same PPM panel. The radio PPM data for these stations has been produced and analysed, and are the subject of this paper. Background The Personal People Meter is an audience measurement system developed by the Arbitron Company in the United States. Co-operating broadcasters place an identifying audio code and a time stamp in their output using a special encoder. A sample of the population is equipped with a small carry-around device similar to a pager, which “listens” for, detects and stores these codes. The PPM therefore provides a near-passive record of the sample’s exposure to encoded media (Patchen and Webb, 2002; Pellegrini and Purdye, 2004). The BBM Canada PPM Television panel in Québec currently has an installed base of about 550 homes, of which about 375 are in the Montreal Extended Market. Data from the panel have been used for two years as the basis of trading television time in Quebec. The panel is selected in a two-step procedure. A large Establishment Survey is used as the master sample from which the actual audience panel is selected, using stratified random procedures. Viewing data from respondents is collected and edited on a daily basis: respondents are accepted into tabulation provided they meet fixed qualification rules, the most important of which is that the PPM has shown at least four hours of carry time during the preceding 24 hour period, as indicated by a built-in motion detector. On an average day, about 90% of the installed panel is accepted into production. The Québec PPM panel is a French- language panel, comprising those who speak French most often at home. Although now operating solely as a television measurement panel, the majority of radio stations in Montreal have also allowed their signals to be encoded. Currently, the encoded stations account for over 92% of all radio listening in the Montreal extended market. The data is currently processed and edited, using the television compliance and qualification rules, although it is not released to BBM members so as not to disrupt the market which obtains its currency through a diary methodology. © Copyright by ESOMAR® / The ARF Station to station 3 The standard measurement instrument for radio in Canada is a personal diary. The diary is a one-week record of radio listening with a fresh sample selected for each week of an eight-week “sweep” period. There are two such sweep periods per year. The sample of homes is selected at random and contacted by telephone. Those homes co-operating in the telephone survey are sent radio diaries to complete. All members of contacted households are sent a personal diary covering a one-week period (Monday through Sunday). Diaries are edited on a weekly basis – the diary must be acceptably completed for each of its seven days in order to be accepted into tabulation. The diary has a time grid for each day, marked into quarter hours. Respondents are asked to keep a record of their radio listening in this diary by entering into the grid the call letters or frequencies of stations listened to, together with the location of listening. It is important to note that this diary format is significantly different from that used by Arbitron (which is much more open- ended), or indeed the RAJAR diary in the U.K. (which is more closed-ended). As the diary is the currency for radio audience measurement, any movement to electronic measurement necessitates a careful comparison and analysis of the competing methodologies. We now have two diary sweep periods during the life of the TV PPM panel within which we can compare radio audience measurements. The Spring 2004 sweep extended from February 16 through April 11, 2004 while the Fall 2004 sweep was from September 6 through October 31, 2004. The standard geographic area used for analysis by the radio industry in Canada is the Montréal Census Metropolitan Area (CMA) as defined by Statistics Canada. However, the comparisons in this paper are made on a somewhat larger area, the Montreal Extended Television Market (EM). This was dictated by the sampling and weighting structure of the PPM panel, which, as noted earlier, is specifically designed for television measurement. Diary data were also processed for this larger area. The Montréal CMA has about 80% of the population of the EM. For purposes of the comparisons, “Radio Listening” is defined as the sum of listening to the 20 (Spring) or 22 (Fall) encoded radio stations, for both PPM and the diary survey. For the Spring 2004 survey, the weekly diary sample was on average 576 people aged 12 years and over, for a total of 4,609 respondents over the eight weeks of the survey. The PPM panel averaged around 548 people aged 12+ years per week. It would be easy to make the comparison of 4609 vs. 548 diaries and dismiss the PPM sample as “too small”. However, we need to keep in mind that the PPM sample is a panel: theoretically, the same sample is used for eight weeks. This does not mean that it is worth 8 x 548 = 4384, but the “re-use” factor means that the effective base is considerably © Copyright by ESOMAR® / The ARF 4 Pasquale (Pat) A. Pellegrini, Ken Purdye more than 548. For the Fall 2004 sample, equivalent figures were 794 for the diary and 641 for the PPM panel COMPARATIVE ANALYSIS RESULTS During the Fall 2004 sweep survey, the average diary respondent listened to the radio for 2.6 hours per day. The equivalent figure for the PPM panel at the same time was 2.0 hours per day. On the face of it, PPM shows about 20% less radio listening in total than the diary. However, this is to ignore an important difference in definition. The diary collects information for each quarter hour during the week. Respondents are asked to count themselves as listening to radio for a specific quarter hour if they listen to at least five minutes within it. They are then counted as having listened for the full fifteen minutes. Radio listening, according to the diary, is essentially an agglomeration of quarter- hour cumulative audience estimates. The PPM rules used for these comparisons are identical to those used for the commercial TV panel: exposure is recorded on a continuous basis and then summarized by minute. A minute is counted as listening if at least 31 seconds of exposure occurred. Each minute is counted as a full minute of listening. We can simulate the diary definition of listening with the PPM data by counting a quarter hour as “listened to” if the respondent listened to at least five minutes of radio within it. In all such cases, the full quarter hour is then credited as listening, as with the diary. When this is done, the PPM and diary data become much closer: The average PPM panel respondent listened to 2.6 hours of radio per day, about the same level as the diary. Our comparison of BBM data for the Spring 2004 sweep period shows similar results. The listening estimates were 2.6 hours per day for the diary and 2.5 hours per day for PPM. Arbitron’s comparison of diary and PPM in the first year of the Philadelphia test showed almost equal quarter hour ratings for the two methods, when adjustments were made for the definition of radio listening (Patchen and Webb, 2002). However, the two measurement systems (PPM and diary) differ in how they arrive at the common 2.6 hours of listening per capita, per day. With the diary system, 69% of respondents listened to radio at all on an average day, and they listened for 3.7 hours each. PPM shows more people listening to radio, but they listen less. According to PPM, more people listened to radio on an average day (81% of respondents) but they listened for a shorter period of time (3.1 hours).