"Over the past fifteen months we have institutionalized a focus on process improvement and invested substantially in our Media infrastructure," Nielsen Executive Vice President-Global Business Services Mitchell Habib wrote in a letter explaining the cause to advertisers, agency and network clients on Wednesday.
Habib said Nielsen had systematically conducted "failure mode effect analyses" for many of the critical processes used to produce its national TV ratings, and has made a variety of improvements, but he acknowledged that Nielsen had failed to do so for its most critical component - the computer servers that support its meter data collection process - because that system was thought to be "a very stable part of our environment" and was a low priority for assessment.
"As a result, a firmware bug from the server manufacturer went undetected and caused a data collection stoppage over the weekend," Habib disclosed, adding, "In the course of fixing this issue, we uncovered a second defect on Monday which resulted in further performance degradation and delays."
Those delays have led to a near black out of national TV ratings reporting so far this week, and Habib said they have been further delayed on purpose, because Nielsen opted to have its scientists take additional time to analyze and "validate the integrity of the data" before releasing it for the week.
He said Nielsen anticipated being "fully back on schedule and caught up" on all its national TV ratings reporting by the end of the week.