Here's why Netflix cancels successful shows

The recent Netflix "What We Watched" data was a fascinating insight into Netflix's most-watched movies and shows – but it also raised a really interesting question: why did Netflix cancel shows that were doing seriously big numbers?

If you look at the data you'll see that many cancelled shows were very popular. Take Shadow and Bone, for example: it was just outside the top 30 shows for the year worldwide, so it was a huge hit, and it racked up more viewing hours than Black Mirror, one of the jewels in Netflix's crown. Despite that, Netflix decided not to continue with it. 

The answer might well be in a new study by analytics firm PlumResearch, as reported by industry bible Variety (paywall). While the study only looked at US data, it provides an insight into what factors Netflix takes into consideration when it's deciding which shows to keep investing in. 

When is a hit not a hit?

One of the key figures appears to be the completion rate, which tells you how many people binge-watched a full series and how quickly they did it – so for example the gothic comedy drama Wednesday had a 65% completion rate in its first month of streaming. Those are good numbers, as are the ones for Squid Game: The Challenge: its completion rate was 50% in just seven days.

Compare that to the mystery ship-based thriller 1899. It too racked up serious viewing numbers – nearly 20 million in the first month – but the completion rate never went above 35% and fewer than 65% watched more than one episode in one sitting. That means the show wasn't as sticky as Netflix might have hoped: lost of people gave it a go, but comparatively few viewers found it compelling.

Of course, the full picture for any show is much more complex and will involve more factors than just completion rates. But with streaming costing more to deliver and facing more competition than ever before, it's clear that streamers need to consider more than just viewing hours when they're deciding where to spend their money – and with all the streamers cutting back on their spending, the focus will increasingly be on the shows that don't just attract an audience but that keep them glued to the streams.