TV ratings across the country were not released Tuesday, thanks to a five-hour power outage in the early morning hours at the Oldsmar facility where the Nielsen Co. processes data.
Nielsen's release of overnight and weekly ratings data was affected by the event, when a transformer blew about 2:05 a.m. Tuesday sending a surge of electricity through the company's power systems, according to spokesman Gary Holmes.
Though Nielsen's sprawling, 475,00-square-foot facility has backup generators, the surge knocked out power for an hour, delaying the processing of data for national programs and local TV markets across the country, Holmes said.
"We have backup plans for hurricanes, and we do test for the possibility that the building will be struck by lightning," he said. "This was an unforeseeable, unprecedented event."
The company generally downloads viewership data to Oldsmar from thousands of sample homes in the early-morning hours to create its ratings reports. Holmes could not predict when data would be available, though the company now hopes to provide some information to its clients today.
In May, Nielsen faced criticism for computer server problems, which kept the company from releasing ratings data for days, just as networks were deciding which series to cancel at the end of the 2008-09 TV season. The current outage comes during the November "sweeps" ratings period, when some smaller TV markets use data collected by written diaries to help tabulate viewership data.
Because Nielsen is the only company that provides the viewership information the TV industry uses to sell advertising space, the steady functioning of a multibillion-dollar industry hangs on its smooth operation.
A spokesman for Tampa Electric Co. said the outage affected about 60 customers in the area; repair crews have not determined what caused the problem.