Twitter users in the United States are younger, better educated and more left-leaning than the general population, a survey showed on Wednesday.

The Pew Research Center study found that those using the micro-blogging platform are more likely to come from higher-income brackets but that their gender and racial or ethnic makeup is largely similar to the adult population as a whole.

The Pew analysis indicates that 22 per cent of American adults use Twitter — far less than the 69 per cent using the leading social network Facebook.

Twitter users are younger, more likely to identify as Democrats, more highly educated and have higher incomes than US adults overall, Pew researchers found.

The median age of adult US Twitter users is 40 — seven years younger than the overall population.

The survey found 42 per cent of adult Twitter users have at least a bachelor's degree, compared with 31 per cent for the general public.

And 41 per cent had a household income above $75,000 — nine points greater than the general population.

The researchers found 36 per cent of those surveyed identify with the Democratic Party, compared with 30 per cent of all US adults, while 21 per cent said they identified with Republicans, in contrast with 26 per cent of the US population.

Only 14 per cent of Twitter users characterised their political views as “very conservative” compared with 25 per cent of the overall population.

Similar shares of Twitter users and US adults identify as “very liberal".

The survey found 90 per cent of Twitter users rarely tweet, while the active 10 percent are responsible for 80 per cent of all tweets created by US users.

The median Twitter user posts two tweets a month, follows 89 accounts and has 25 followers.

The “active” tweeters are much more likely to be women — who make up 65 per cent of this group — and more likely to say they regularly tweet about politics, according to the researchers.

The survey comes amid intense pressure from US President Donald Trump and his Republican allies who claim that Twitter and other social platforms are biased against conservatives — a claim roundly rejected by the companies.

Pew surveyed 2,791 US adults in November and December 2018 who were willing to share their Twitter handles — enabling the researchers to analyse the content from their accounts. The margin of error for the study was estimated at three percentage points.