How Grey’s Anatomy Toppled ER As Prime-Time TV’s Longest-Running Medical Drama

Photo: ABC

When NBC’s ER aired its series finale back in April 2009 — wrapping up after 15 years and 331 episodes — it signed off as the longest-running medical drama in prime-time TV history. A decade later, that record is about to fall: Barring a last-minute preemption, Grey’s Anatomy will air its 332nd episode tonight at 8 p.m. ET on ABC. It’s an impressive milestone for sure, but what’s even more amazing than Grey’s longevity is how massively popular Shonda Rhimes’s creation remains with audiences so far into its run. In honor of this week’s milestone episode, Vulture dove deep into the Nielsen data to quantify exactly how much America still loves the sexy surgeons of (the hospital formerly known as) Seattle Grace.

Fourteen years after its premiere, Grey’s is still the biggest hit on ABC …

Even though its first episode aired all the way back in March 2005 — during the early days of George W. Bush’s second term — Grey’s currently ranks as ABC’s No. 1 series (comedy, drama, or reality) among adults under 50, the network’s demographic target. So far this season, the show is averaging a 3.1 in the demo, more than 20 percent ahead of the Alphabet’s No. 2 series (Modern Family and the much younger MD drama, The Good Doctor), both of which are currently averaging a 2.5 rating.

… And it’s the No. 2 drama on all of broadcast TV

Grey’s isn’t just a hit within the ABC universe. Its 3.1 demo rating puts it behind only NBC’s still-hot This Is Us (4.0 demo rating) among dramas airing on the six broadcast networks. (The only cable drama this season that outrates it is AMC’s The Walking Dead, though there’s a good chance that HBO’s Game of Thrones will catapult ahead of every show on TV once its final season arrives in April.) To put this in context, when ER was at the same point in its run as Grey’s, during the 2008–2009 television season, it enjoyed much less relative success: It ended its final year as the No. 12 drama on broadcast TV, and that was even with a big boost at the end from its series finale. (In ER’s penultimate season, it ranked behind 13 other dramas, including the low-rated and short-lived NBC reboot of Bionic Woman.) To be fair, ER was notching higher overall ratings in 2009 than Grey’s is delivering now, but that’s because nearly everything on TV drew a bigger audience a decade ago.

Women who were toddlers when Grey’s debuted are among its biggest fans …

While This Is Us has a relatively big lead over Grey’s among all adults under 50, the gap virtually disappears when it comes to millennial women. Per Nielsen, just one-tenth of a rating point separates the NBC and ABC dramas among women aged 18 to 34. This Is Us is currently averaging a 3.5 rating in the demo, while Grey’s is at a 3.4, making the shows the No. 1 and 2 series on all of TV among young women. This means the youngest members of the 18-to-34 demo were barely 4 years old when Meredith and McDreamy first met. This concentration of younger eyeballs helps keep the median age of Grey’s viewers relatively young, at 54 years old. That’s younger than the median ages of medical drama rivals such as Fox’s fledgling 911 (55.2), NBC’s freshman New Amsterdam (59.1), ABC’s own The Good Doctor (60.2), and NBC’s positively geriatric Chicago Med (61.9).

… And Netflix has helped lure those younger viewers

While Netflix doesn’t release ratings information, ABC execs have been vocal in expressing their belief that the existence of Grey’s on Netflix the last few years has helped bring new viewers to the show’s linear broadcast on Thursdays. During the 2014–2015 season, the series did something almost unheard of for a show then in its tenth season: Its overall audience and demo ratings went up. It wasn’t a massive leap — somewhere between 5 and 10 percent, depending on the metric. But one ABC exec told the Los Angeles Times in 2017 that the network was convinced that teenage girls “were discovering Grey’s for the very first time” on Netflix and then getting into the habit of watching new episodes on ABC. That same year, former Disney/ABC TV Group boss Ben Sherwood told an audience that the company believes an average of 200,000 viewers were bingeing Grey’s from the beginning each month — more than 2 million per year.

Grey’s has stayed at (or near) the top of the ratings every year it’s been on TV

One of the most impressive aspects of Grey’s success has been how consistently it brings in viewers. It debuted as part of one of the most successful freshman classes of new series on any network, launching the same season as ABC’s Desperate Housewives and Lost, iconic hits in their own right. That first year, Grey’s — with a limited run of nine episodes airing in the spring of 2005 — landed as the No. 3 drama on network TV among adults under 50, finishing behind only Desperate Housewives and CSI. Amazingly, Grey’s has never ranked any lower than No. 3 among network dramas in the demo. During its first full season (2005–2006), it edged past CSI to the No. 2 slot and then spent several years fluctuating between No. 2 and No. 3. In its sixth year, Grey’s finally ended a season as the No. 1 broadcast drama in the demo, and stayed at No. 1 for two more seasons. It was briefly displaced from the top spot during the 2012–2013 season (and just barely) by Fox’s limited-run drama The Following (which aired just 15 episodes versus the 28 installments Grey’s produced that year). But Grey’s returned to No. 1 again for the 2013–2014 season, and has stayed at No. 2 or No. 3 ever since.