Arbitron spokesperson Thom Mocarsky gave the official company explanation of what happened to cause the sudden sharp drop in Houston August Week 1 weekly PPM intab (see story). He says there was actually "no precipitous decline in panelist cooperation in Houston for the week of July 26 through August 1, 2007."
The file used to process the weekly cume estimates (the unified weekly sample) was incompletely loaded from the data warehouse to the production system. "It appears that exposure records for almost 200 panelists who were in-tab 6 of 7 days were not included in that file transfer. This is why the average (unified) weekly in-tab appears to be abnormally low," said Mocarsky. "No exposure records have been lost. The error affected the calculation of weekly cumes. We need to find out what caused the processing error. We need to correct the file and reprocess the PPM weekly data. Please note: The average quarter hour estimates and the daily cume estimates are NOT likely to change. These estimates are based on the average daily in-tab sample which appear to be correctly reported on the Sample Composition. We will provide more details shortly."