GMC chief executive Niall Dickson said revalidation would evolve, but at first 'will not be perfect'. At the start, revalidation will be a 'minimum', he said, but over time it will develop and the quality of information used in revalidation will improve.
Mr Dickson said that when revalidation is first implemented it could be possible that, a year after a doctor got through, an issue might emerge about their fitness to practise.
'That does not mean that the whole system has failed,' Mr Dickson said. 'It means that we need to start off with something that is practical and proportionate and that we start to encourage more self-reflective practice, which we think is one of the really big gains of this.'
Mr Dickson said that he hoped that, over time, revalidation would become more outcome-orientated as the quality of data it collected improved.
'We want to get something that is useful, but it will not be perfect, and it will change and develop as we learn once the system is up and running,' he said.
The GMC said last week that responses to its consultation on revalidation suggest there is strong professional and public support for the scheme.
The GMC said there was 'strong backing' for many of its proposals, which include the move to a single, more streamlined process. Mr Dickson said: 'The positive responses to our consultation have been enormously encouraging and demonstrate continuing support for revalidation.'
A full report on the consultation, including a revalidation timetable, will be published in October, the GMC said.