Contrary to the popular perception that young people are all viewing video online rather than watching traditional television, it seems that those aged 16-34 account for only a fifth of BBC iPlayer viewing on computers and tablets.

BARB, the audience measurement organisation in the United Kingdom, measures online viewing in addition to traditional television. The majority of the 5,000 or so homes in its demographically representative panel have software meters attached to their computers and tablets that track their online viewing. Panel members have to register who is in front of each device.

Smartphones are not yet monitored in this way. The researchers claim that the risk of panel homes deciding to leave the measurement system is not matched by the benefit of collecting this data.

BARB says that television viewing on computers, tablets and phones adds just 1.5% to television viewing, and of this only 18% of viewing was on a phone.

BARB is exploring the use of router meters as a method of monitoring household viewing across all devices, including phones, although this would not account for out of home viewing or usage on mobile networks.

Despite these limitations, an analysis of viewing on computers and tablets in 2017 as measured by the BARB panel homes is instructive and may surprise some industry observers.

It shows that across all the video players measured, for the BBC, ITV, Channel 4 and Sky Go, viewing by those under the age of 35 accounted for a third of viewing time. Around a third was by those aged 35-54 and a third was from those aged over 55.

Less than a quarter of viewing on computers and tablets was among those aged 16-34, a group that one might expected to be over represented. In fact, this age group only accounts for 15% of all television viewing.

Age profile of online player viewing, 2017: Source: BARB panel

There was some variation between the broadcasters. For the BBC iPlayer, the 16-34 year-olds only accounted for 20% of viewing on computers and tablets, compared to 40% of viewing on All4, the online brand for Channel 4.

However, the BBC iPlayer accounts for a lot more online viewing than All 4. Of the eight online players measured by BARB, the BBC iPlayer accounted for over half of all viewing minutes in 2017. Sky Go came next with 19%, followed by ITV Hub with 17% and All Four with 11%. My5 and UKTV only accounted for 1% each.

So how does this compare to figures provided by the BBC? Well the BBC has been rather irregular in providing performance data about the iPlayer beyond headline figures. The most recent published report we could find was from September 2017.

The BBC reported that BBC iPlayer viewing remains strongly under 55 in terms of age, with a younger audience profile than television. Its figures show that 44% of users in the previous four quarters were aged 16-34, with 40% aged 35-54, and only 17% aged over 55. The proportion of BBC iPlayer viewers aged 35-54 has increased in recent years, up from 35% in 2014.

The BBC figures also refer to users, rather than usage, which is an important distinction. The BBC numbers also related to all users of BBC iPlayer, of which television devices make up nearly half of all requests. According to the BBC, requests from computers and tablets make up 15% and 25% of online requests for television programmes, with mobile accounting for 12%.

It is a bit of a mystery how the BBC determines the demographics of its iPlayer users. The BBC now requires registration, so users have to give their date of birth, gender and postcode. However, this only applies to some platforms and there is no way of knowing if the information provided is accurate. The BBC has not published recent demographic data since it required registration.

The BBC says that those aged 55 or over represent 37% of all television viewers. According to the current BARB universe, these 19.40 million people aged over 55 account for 32% of all individuals and 38% of all adults in television homes in the United Kingdom.

However, this age group watches a lot more television. Those aged 55-64 watched an average of 4.78 hours a day in 2017, while those aged over 65 watched for 5.72 hours a day. In comparison, those aged 16-24 watched for an average of 1.67 hours and those aged 25-34 watched for 2.33 hours a day. So the older viewers are watching two to three times as much television.

Going back to the BARB panel figures, those over 55 account for 38% of online viewing. That is consistent with their representation by population, but not surprisingly less than for television viewing in general.

Nevertheless, online viewing is clearly not restricted to millennials. In fact, the proportion of computer and tablet viewing on the BBC iPlayer by this age group is less than their proportion of the population would suggest.

The 16-34 age group represents around a quarter of the country, being 24.73% of the population of the United Kingdom in the middle of 2016, according to the Office of National Statistics.

Yet this group accounts for only 19.61% of viewing of the BBC iPlayer on computers and tablets, according to BARB. Of course, this is only based on a representative panel of some 5,100 homes.

The implication is that this 16-34 age group may be watching more on computers and tablets than one might expect from their television viewing, but they are still under represented in online viewing relative to the general population.