• by David Goetzl  @dgoetzl, January 29, 2009

Starting Friday, network executives will have to wait a little longer for prime-time results from the previous night. As Nielsen readies for the planned digital switchover, it is delaying release of overnight ratings by some four hours--at least for now.

The first ratings streams, which have traditionally come in as early as 7 a.m. EST/4 a.m. PST., are household numbers only. Now, they won't cross the wire until near 11 a.m. EST/8 a.m. PST.

The delay is the result of a test that Nielsen is conducting as it looks to iron out any potential disruptions caused by the Feb. 17 digital transition. However, the delay could be abandoned as soon as next week.

The government is expected to postpone the switchover date until June 12--something Nielsen reiterated in a client memo sent Thursday. Nielsen would then drop its test--before resuming it closer to that time.

Still, the House of Representatives has voted down one bill that would postpone the switchover to June. But the Obama administration continues to press for it, and many in Washington expect the House will take up the measure again next week--this time pushing for a majority versus two-thirds approval necessary for passage.

As Nielsen's release delay goes forward, it is expected to make an exception Monday; it plans to deliver Super Bowl results by 9 a.m. EST.

Under Nielsen's test plan, it will also delay release of another-- perhaps more important--stream of ratings known as the "fast nationals." The figures traditionally have come in at 11 a.m. EST, but will be put off until a 1 p.m. EST release.

These numbers provide a first look at how shows did among various demos, notably the 18-to-49 segment. And they offer a first look at how DVR use affected viewing--with the first release of "live plus same day" ratings.

Official final Nielsen numbers will experience no delay and continue to be reported at 4 p.m. EST.

Those first 7 a.m. results--the so-called "metered market numbers"--are derived from performance in a subset of the 56 large markets. The "fast nationals" come from Nielsen's 16,000-home nationwide sample.

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