Credit: by Casey Fiesler on Flickr. Some rights reserved
The story of a high school murder in 1990s Baltimore, and an investigation into the details of the case, made the unlikely subject of the most popular podcast ever: Serial.

Produced as an offshoot of This American Life, a famous product of the WBEZ Chicago radio station, Serial has now had more than 75 million downloads since it first appeared online last October.

At a BBC event on the future of audio yesterday, Dana Chivvis, producer of Serial, said the team had set out to "prove radio can be as good as TV" and to make it "appointment listening" in the same manner as people will tune in to watch their favourite TV shows.

It was intentionally designed with a TV show in mindDana Chivvis, Serial
They certainly succeeded, turning the weekly podcast into a global phenomenon that generated think pieces, conspiracy theories, subreddits and a so-called "Serial-mania", but what actually made it work?

"It was intentionally designed with a TV show in mind," said Chivvis, "with the same elements as a great TV show: the characters, the plot, a theme song, a 'previously on' recap."

These tried and tested tropes of broadcasting helped to maintain interest and an attachment, Chivvis said, but were supported by a foundation of solid investigative journalism.

Sarah Koenig, the host of Serial, spent over a year on the story, interviewing 70 individuals connected to the case of then-teenager Adnan Syed's conviction for killing ex-girlfriend Hae Min Lee in 1998.

Syed's protestations of innocence formed the backbone of the story, and Koenig spent more than 40 hours in phone interviews with him both before and throughout the production process, all of which was rigorously fact-checked.

Koenig has been quoted as saying Serial is "about the basics: love and death and justice and truth", central features in a gripping story, but the podcast format was central in its success, said Chivvis.

"Previously [podcasts] were a place to do a digital version of a radio show," she said, "or have an unedited conversation with three or four people."

But the weekly serialisation built suspense, while a growing number of previous episodes allowed people to catch up and become hooked on the story.

Podcasts have a very low barrier for entry but you've got to be willing to invest and experimentDana Chivvis, Serial
This "binge-listening" habit is fuelling the growing interest in podcasts, said Miranda Sawyer, the Observer's radio critic, in a similar manner to how Netflix subscribers watch multiple episodes of popular TV series, a habit only made possible for audio with podcasts.

And she stressed the audience for podcasts is often under-estimated, as many UK broadsheet readers in particular are already fans of US podcasts from NPR or This American Life.

Simon Marks, a news anchor, producer and broadcasting consultant also on the panel, warned against a perceived gold rush in podcasts, identifying "some delusion that with the advent of Serial the time of podcasting has come of age".

Serial's success came from its quality, he said, and there is now "so much content out there" compared to the days of the BBC, ITN and smaller stations, that "if you are producing average content then you're wasting your time".

"Today when I sit down to do the most basic report I'm doing the best to incorporate sound and make it the most compelling 27 seconds it can be," he said.

The concept of audience engagement in audio shouldn't be dismissed either, added Marks, despite its history as a purely one-way medium.

The Serial producers explicitly shied away from engaging with their audience, and for good reason, as some listeners began investigating the story themselves.

But at Radio 1's Newsbeat online editor Anna Doble said involving the audience is vital to the central aim of attracting young listeners and involving them in the news.

"We want to hear the audience above the reporters," she said, "and packages that are 90 per cent the audience are the best."

Here lies the central challenge though. The current pre-occupation with social media and shareability as the main distribution model for journalism is almost entirely focussed on a visual hook to draw the audience.

"People don't stop for audio," said Doble, and producers or broadcasters "need to get into that [social media] space and be braver about taking it on" in both a visual and aural manner.

"Podcasts have a very low barrier for entry," agreed Chivvis, "but you've got to be willing to invest and experiment."

All the speakers shared their advice for producing online audio in the clip below.

Correction: Serial and This American Life are in no way affiliated with National Public Radio, as originally stated in this article. Although a common misconception, both are the product of WBEZ Chicago, and this article has been reflected to show as much.

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