When Michael Scott (Steve Carell) prematurely announced the closing of the Buffalo office of the Dunder Mifflin paper company on the season finale of NBC’s “The Office,” more than a third of the audience in Western New York didn’t watch his latest portrayal of cluelessness for up to seven days.

When the wedding of Meredith Grey (Ellen Pompeo) and Derek Shepherd (Patrick Dempsey) didn’t go off on the season finale of ABC’s “Grey’s Anatomy,” about one-quarter of the show’s audience waited up to seven days later to find out why.

That’s because “The Office” and “Grey’s Anatomy” are two network series that get a large percentage of their audience from viewers who record the programs to watch later.

When the number of viewers who watched “Grey’s Anatomy” on DVRs (within seven days) were added to the ratings figures of the audience that watched it live (or the “live” rating), it became the most popular TV series in Western New York during the May sweeps. Before the DVR viewership was added, CBS’ “The Mentalist” was No. 1 here.

The DVR and other playback devices clearly are changing the viewing habits of Western New Yorkers and across the nation.

The latest evidence of the local impact of the DVRs recently arrived along with the demographics for the May sweeps.

The extra ratings points may not satisfy advertisers, who realize that one of the benefits of DVR viewing is speeding through the commercials. However, there is a theory that DVR users get subliminal messages when they speed through the commercials.

In any event, the ratings for “Grey’s Anatomy” in May improved by 37 percent after DVR usage was included, raising a 14.5 live rating for those who watched Derek, Meredith and Izzie to a 19.8 rating live plus seven days. The 5.3 rating point DVR improvement was the highest here.

“The Mentalist,” which had been No. 1 with a 16.4 live rating, improved by 3.2 points and ended with a second-place 19.6 rating live plus seven days.

As a rule, Western New Yorkers watched shows on DVRs at a much higher rate than the national average, which might have indicated that DVR penetration is higher here than it is in other areas of the country. However, Nielsen said the local sample of DVR penetration during the May sweeps was 33.6 percent, which is in the range of the national average and means roughly one-third of homes here have one.

The adventures of Dr. Gregory House on “House” on Fox were second here in the DVR improvement category. It gained 4.0 ratings points or 47 percent to a 12.6 rating.

Nationally, “Grey’s” improved by 24 percent and “House” improved by 26 percent, far below the improvement here.

“The Mentalist” gain of 3.2 points is the same as the performance episodes of “American Idol” (a 21 percent gain) to tie for third place in that category here. CBS’ “NCIS” and ABC’s “Private Practice” gained 2.9 points each, with the “Practice” figure a 31 percent improvement on its 9.3 live rating average.

Other programs in the Top 10 in rating point gains include ABC’s “Desperate Housewives,” NBC’s “Medium,” ABC’s “Lost” and NBC’s “The Office.” “Lost” and “The Office” each gained 2.6 ratings points, increasing the viewership of “Lost” by 38 percent and of “The Office” by 60 percent.

Of course, “The Office” competes with two very popular shows at 9 p. m. Thursday – “Grey’s” and “CSI” on CBS –which undoubtedly contributes to its DVR popularity.

With only anecdotal evidence, one also would guess that the percentage of viewers who record “Grey’s” and “The Office” may have something to do with the fact they air regularly on a night (Thursday) when many people are out and getting an early start on the weekend.

Naturally, some of the shows with the smallest live audiences have some of the larger percentage gains. For example, the CW’s “90210” had as many viewers watching it later on DVRs as it had watching it live. The total rating was only 1.8.

Two other low-rated CW shows, “Supernatural” and “Smallville,” saw 59 percent and 44 percent gains each but still didn’t hit a 3 rating. But “Gossip Girl” only gained 25 percent here to a 2.0.

NBC’s “Heroes,” which saw a huge ratings drop this season, increased its audience by 55 percent after gaining 2.1 DVR ratings points. Fox’s “Prison Break” improved by 61 percent to a 3.7 rating and “Dollhouse” improved by 50 percent to a 2.1. They both aired on Friday nights, when overall viewership is low.

On the other hand, some shows didn’t get any DVR viewership at all—including “60 Minutes,” “Supernanny” and “America’s Most Wanted.”