The May sweep has begun, and this was the week that scripted struck back. After NBC‘s The Voice took the top spots in both total viewers and adults 18-49 during the week of April 15-21, it seemed the show might be poised to lead a reality a win streak, joined by fellow unscripted shows Dancing With The Stars and American Idol, which filled out the rest of the Top 5 most-watched of the week. Idol also came in third overall in the demo. Well, it was a very short streak: Original dramas and sitcoms swung their weight around in Week 31 of the 2012-2013 season.

The Voice’s April 22 broadcast held onto its No. 1 spot in the demo for the week of April 22-28 with a 4.9/14, but CBSThe Big Bang Theory on April 25 took second place with a 4.5/15 to push the second Voice of the week to third. Among total viewers, let’s just say reality was schooled by the broadcast nets as a new NCIS on April 23 took the top spot with 17.332 million viewers, Big Bang Theory was second with 15.050 million and NCIS: LA took third with 14.216 million to beat the Monday airing of The Voice (14.152 million). ABC’s DWTS came in fifth with 13.765 million. April 24’s American Idol was eighth with 12.457 million watching. Long story short, it was repeats that gave Voice such dominance in Week 30. In Week 31, the CBS boys were back in town. It will be interesting to watch this week to see whether the first of NBC’s two weeks of five hours of The Voice pays off, or if Week 30 was really just a one-time treat.

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Despite the changes in the show rankings — which came during the beginning of the sweep April 25 as well the first round of the NFL Draft, which did its traditional job of pushing almost everyone to lows — nothing changed in the network rankings from the week before. CBS was still first in viewers (8.706 million) for a ninth straight week, while Fox held the top spot demo-wise (1.9/6) for a second straight week. However, once one got beyond who was No. 1, things were a bit more spread out and a bit more interesting, with some patterns starting to become solid heading into the season’s last month. In terms of viewership everyone was in the same place — though their numbers changed. CBS was up, but so was Fox (from 5.605 million to 6.056 million). ABC finished second for a second consecutive week, but with Dancing With The Stars dipping, a lot of repeats and new comedy How To Live With Your Parents (For The Rest Of Your Life) down hard, it took a sight tumble (from 6.618 million viewers to 6.435 million). NBC also fell (from 5.557 million to 5.082 million) as its one big show, The Voice, started to see viewership and ratings declines. NBC dipped 2% in viewership from the same week in the 2011-2012 season, while Fox was down 17% and ABC fell 20%. CBS actually saw a gain of 3% year-over-year in viewership.

Even though American Idol hit an all-time low for a regularly scheduled show on April 25, strong NASCAR results and a rising The Following meant Fox held on to the same numbers in the 18-49 demo from the previous frame. In fact, the network found more breathing room as CBS fell to a 1.7/5 from the 1.8/5 it and NBC had before. NBC went down even more from its Week 30 result, to a 1.6/5 in Week 31. With NBC now in third place, ABC was fourth even though it rose from a 1.4/4 the week before to 1.5/5 — despite a Modern Family encore and other repeats. Looking at ratings from the same frame last year, ABC took the steepest fall, down 25%. Like its viewership numbers from last year, Fox was down 17%, while CBS and NBC stayed the same from the same week in the 2011-2012 season.

Season to date, CBS remains No. 1 in viewers (11.998 million), with ABC second (7.821 million), Fox third (7.079 million) and NBC fourth (7.001 million). In the 18-49 demo, the rankings are also the same as last week with CBS first (2.9/8), Fox second (2.5/7), NBC third (2.4/7) and ABC fourth (2.2/6). Everyone’s fully loaded for this first full week of the sweep, but unless there is a dramatic shift soon, those will be the rankings at the end of the season next month.