Nielsen says software error led to errors in television measurement

Markets Associated Press

The Nielsen company says they have discovered errors in their measurement of television viewing that incorrectly showed people were watching one network when in fact they were tuned in to another.

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The company said Friday it is investigating a software error that has been producing faulty data since March, but only became apparent in the past few weeks as viewership increased with the beginning of the new fall season.

Nielsen would not comment on who has benefited or been hurt by the errors. But it appears ABC was the beneficiary; in the past few weeks the network saw repeated, unexplained gains between preliminary viewership estimates made early in the morning and more complete national data that becomes available later.

Nielsen's measurements affect billions of dollars in advertising spending.