'Stranger Things' Will Be Netflix's Biggest Hit Yet. How? Netflix Changed its Rules

Stranger Things returned Friday with season 4. By the end of the summer, Netflix will almost certainly proclaim the retro sci-fi series' latest season its biggest hit yet. But Stranger Things 4's viewership victory, set to trump the likes of Bridgerton and Squid Game, was assured weeks before a single subscriber streamed a second of it, when Netflix quietly tweaked its own popularity rules.

The change last month has already inflated the stats for shows like Ozark and Money Heist. Stranger Things 4 is next.  

When the final numbers are in, Stranger Things 4 will likely eclipse Bridgerton and Squid Game in Netflix's all-time Most Popular rankings based on total hours watched. These are charts that Netflix updates weekly at Netflix Top 10. All three shows are colossally well-watched worldwide. But among them, only Stranger Things will enjoy Netflix counting its "watch time" for twice as long. Instead of tallying up viewing hours in its first 28 days of release, as Netflix did for Bridgerton and Squid Game, Netflix will be racking up Stranger Things 4's views over 56 days total thanks to its two-part release schedule. 

While these charts can be dismissed as pageantry without much consequence, they're still the most direct data available pointing people -- whether it's Wall Street suits, Hollywood insiders or viewers like you -- to the biggest titles on the world's largest streaming service. They give investors a gauge for Netflix's competitiveness, they can help Netflix recruit talent, and they stoke buzz that may nudge you to watch something you otherwise wouldn't. 

But Netflix measurement is about to take on much greater consequence, as the service launches advertising. For Netflix to be able to offer you a cheaper tier with ads, it will need to broaden its measurement beyond watch time and get more transparent in order to win over advertisers, experts say. 

Netflix has gotten by this far releasing whatever data it wants on its own terms, said Dallas Lawrence, the head of communications and brand for Samba TV, a television researcher and ad measurement firm. That will change when Netflix must sell itself to advertisers too. 

"The buyers will not allow Netflix to grade its own homework," Lawrence said. 

Watch time turned upside down 

When Netflix launched its Top 10 rankings website in November, it unlocked an unprecedented trove of viewing data. The site details the service's most-watched titles of the previous week and how many hours they were viewed, both globally and in more than 90 individual countries. For its most voraciously viewed titles, Netflix updates a set of Most Popular charts, which rank its most watched originals of all time. 

And for a show or movie to make it on the all-time Most Popular rankings, Netflix looks at the 28 days from its premiere to rack up watch hours. 

The latest season of Bridgerton, for example, is Netflix's most watched show in English at 656.3 million hours. Squid Game, the breakout South Korean dystopian thriller, is Netflix's most-watched show in any language, at 1.65 billion hours watched in the 28-day window. 

That 28-day shot clock was the same for every movie and TV season, until May 10. Then Netflix quietly tweaked the rules to give some shows 56 days -- twice as long -- to amass views. For any series that releases its season in two "volumes" on different dates, the shot clock runs for 28 days after its first batch of episodes, then it resumes again for an additional 28 days after the second batch. Netflix counts the viewing of a volume's episodes only during that volume's first 28 days.

But shows like Stranger Things 4, with seven episodes out now and another two coming July 1, still get 56 days to generate viewing hours toward their ranking. And because the release of a second volume can come soon after the first, the first 28-day window can potentially include rewatch views of the first batch as fans catch up as the second approaches. In the case of Stranger Things 4, fans who immediately binge-watched volume one could revisit these episodes to refresh in anticipation of volume two. And any of that rewatching before June 23 would count.

Shows like Bridgerton and Squid Game, which followed the Netflix convention of releasing a full season at once, are still stuck with their count over 28 days.

Netflix disclosed this change by, essentially, updating its fine print. Judging by archived screenshots of the Top 10 website, Netflix added two sentences to its methodology statement on May 10. Netflix didn't otherwise disclose that it had altered its methodology for the Most Popular rankings.

When reached for comment on this article, Netflix referred to the methodology stated on its site.

Stranger Things 4 was already sure to be a smash by Netflix's standards. Its last season is among Netflix's most watched programs ever, even though it came out when Netflix had two-thirds the subscribers it does now. A three-year hiatus has built up fan demand, and this season's runtime is much longer than the rest. (Its runtime is also much longer than that of Squid Game or Bridgerton. Its first volume of episodes runs an hour longer than the entirety of Squid Game or Bridgerton's whole last season, and Stranger Things 4 still has nearly four hours coming July 1.)

But May's methodology change stacked the deck in favor of Stranger Things. It has already generated 286.8 million hours in the first three days of availability. With 53 more days on its shot clock, it needs to generate less than a tenth of that daily to accumulate enough watch time to become No. 1. 

Overnight sensations

The rule change has wildly inflated the watch time for several other shows already. Multiple programs suddenly appeared in Netflix's top 10 charts or shot to a much higher ranking, with hundreds of millions of hours suddenly added to their counts. 

Money Heist is a hit Spanish thriller series also known as La Casa de Papel. Its final season was released in two volumes, with five episodes landing on Sept. 1 and the last five episodes arriving Dec. 1. After the methodology change in May, its watch time more than doubled. Money Heist is now positioned as Netflix's No. 2 most watched show of all time regardless of language, right after Squid Game. Before the rule change, it didn't even make the top 10. 

Other shows have gotten big bumps too. Fantasy police procedural Lucifer released half its fifth season in 2020 and the other half nearly a year later. Lucifer had been absent from Netflix's Most Popular rankings since they launched, but in May, it suddenly appeared as Netflix's No. 7 most-watched program in any language. The latest season of the drama Ozark, released partly on Jan. 21 and partly on April 29, needed three extra weeks of streaming after its original 28-day window to make the English language top 10. 

Netflix's Top 10 website still characterizes the watch time of all these shows as hours viewed in their "first 28 days on Netflix."

To bolster the credibility of its stats, Netflix recruited accounting firm EY -- formerly known as Ernst & Young, one of the world's biggest accounting companies -- to vet its data. But EY finished its first Netflix report in February, long before Netflix revised its methodology. And EY's report was a light-touch vetting called a review, which essentially accepts the measurement criteria as Netflix defines them and then verifies that the data abide by those rules. Netflix has no existing plans for another accounting review.

Grading its own homework

Netflix was notoriously tight-lipped about its viewership for years. Beau Willimon -- creator of House of Cards, which put Netflix's original programming on the map -- once said the company wouldn't even share audience metrics with him. But since 2018, Netflix has grown more open about the popularity of its shows and movies, culminating with its Top 10 website. 

For Netflix to start offering you a cheaper tier with ads, it needs to actually win advertisers -- and advertisers won't go by Netflix's numbers. Because TV advertising is so expensive, brands and agencies want measurements comparable across services, so they can know what they're getting at Netflix versus Paramount Plus versus Disney Plus, said Needham senior analyst Laura Martin.

Netflix "can do weird things, like introduce new measurement," added Martin, who has called for Netflix to add advertising for years. "But it would slow adoption by advertisers."

Traditionally, advertisers evaluated TV programs by how many people tuned in. "As we enter this new phase, transparency around viewership data is going to be essential, especially on 'closed' platforms" like Netflix, said Anjali Midha, co-founder and CEO of Diesel Labs, a media intelligence firm. Viewership will naturally remain important, she added, but so will demographics, psychographics and other metrics of watching behavior.

But Netflix's own reputation as the gold standard of streaming TV will work in its favor, Lawrence said.

"Streaming has historically been rife with a myriad … sites that still seem like the Wild West, fraught with risky content," he said. 

Advertisers may come to welcome Netflix's safety and scope, even if its own measurement rules still shoot from the hip. 

Correction, 6:07 a.m. PT June 2: An earlier version of this story suggested Netflix may count viewing of all episodes from split-season shows over a full 56 days. Netflix counts the viewing of episodes only within 28 days of their release, but split-season shows get two 28-day periods -- 56 days total -- to amass watch time.