Its decision further cements the distinction between the 24-strong body and the rest of the sector.
In its latest analysis of graduate destinations, the ONS found that 67 per cent of Russell Group graduates were in a high-skilled job, compared to 53 per cent of those that went to other universities.
Graduates from the group - the “top UK universities”, as the ONS puts it - earned an average of £18.60 an hour, compared with £14.97 for the rest.
This is likely to be because Russell Group students are more likely to study medicine, engineering, or physical or environmental sciences – subjects that were more likely to lead to highly skilled and paid jobs – and because the universities have higher entry standards, the ONS says.
A spokesman for the ONS said that it had broken down the data in this way because it had been requested by users of the statistics.
It had also been made possible because the Labour Force Survey, on which the analysis is based, had started asking graduates where they went to university.
The ONS’s distinction comes after the 1994 Group, which once sought to contest the Russell Group’s “elite” tag, announced it was disbanding earlier this month.
According to the ONS figures, as of April to June 2013, graduates had a better employment rate (87 per cent) than those educated to A-level standard (83 per cent).
But 47 per cent of recent graduates were working in non-graduate roles, Graduates in the UK labour market 2013 found, up from 37 per cent in 2001.
This proportion had risen particularly sharply since the recession in 2008-9, possibly because of a reduced demand for graduate-level skills and an increased supply of graduates, it says.
It defines non-graduate work as a role where a degree is not required, such as for secretaries, sales assistants, factory workers and care workers.
There was further grim news for graduates in a separate analysis by the Financial Times, published on 19 November.
It found that new graduates in 2011-12 were earning on average 12 per cent less at the same stage of their careers than those who left university just before the financial crash of 2008. Student debt has also risen on average by 60 per cent over the same period, it reported.