Schools are still being forced to lay on "jazzy" lessons because many inspectors are fixated with outdated styles of teaching, a think tank has said.
In a highly-critical report, Civitas accused Ofsted of being biased towards "trendy" child-led learning, such as group work and role play, and prejudiced against teacher-led classes, such as working from a textbook.
It argues that despite chief inspector Sir Michael Wilshaw insisting that Ofsted no longer has a preferred teaching style, any changes have been cosmetic and favouritism for certain methods has continued.
The study, by Robert Peal, a history teacher and education research fellow for the right-wing think tank, is based on an analysis of 260 Ofsted reports.
The first 130 reports, from secondary schools inspected between September 10 and October 13 last year, showed clear evidence of bias, Civitas claimed, with more than half (52%) showing a preference for lessons in which pupils learn independently from teacher instruction.
More than two-fifths (42%) showed a preference for group work, its study says, and just under a fifth (18%) criticised teachers for talking too much.
At the end of last year inspectors were issued with new guidance saying they should not show a preference for a particular teaching style and Sir Michael has insisted that there is no right way to teach.
Earlier this year he told inspectors that they should not criticise a lesson because it does not conform with a particular view on how children should be taught.
To examine the impact of these changes, Civitas examined a further 130 reports of secondary schools inspected since January.
It found that only eight per cent showed a preference for pupil independence and none criticised teachers for talking too much.
The study said: "Further research suggests that this change in the language of written reports is superficial."
Since May, inspectors have been issued with a list of "banned phrases" that they cannot use, the study says, such as "teacher talk dominates too many lessons" and given alternatives to use instead.
In some cases, reports have been edited after they were published to delete child-centred language.
While the language has changed, judgements have not, Civitas suggests.
"Such a shallow approach to combating the preferred Ofsted style of teaching relies on changing the language of the reports, but allowing the fundamental judgement to remain the same," it says.
The study goes on to say that some people had told the think tank that inspectors still show a favouritism for child-led learning when they give verbal feedback to teachers and school leaders.
It calls for the quality of teaching grade to be removed from inspections, with schools graded on achievement, behaviour and leadership and management.
"This would alleviate the professional culture created by Ofsted which is distinctly in favour of child-centred teaching methods, and prejudiced against more teacher-led alternatives.
"Teachers are accustomed to putting on 'jazzy' lessons, replete with group-work, role play and active learning in order to fulfil what has become widely acknowledged as the 'Ofsted style'.
"So strong is the inspectorate's reputation for favouring trendy teaching methods that the idea of putting on a 'chalk and talk' lesson or learning from a textbook with an Ofsted inspector in the room has become inconceivable within the teaching profession."
In his foreword to the study, Civitas director David Green said: "The reality now is that many schools no longer know what Ofsted expects.
"Individual inspectors, still under the influence of discredited child-led approaches from the 1960s, may penalise them because they are enthusiastic about teacher-led professionalism; others may not."
An Ofsted spokesman said: "The arguments put forward in this report are largely re-heated ones.
"What matters to Ofsted is what matters to parents: ensuring that schools are delivering the best possible education for their children.
"As HM Chief Inspector, Sir Michael Wilshaw, has repeatedly made clear, Ofsted does not have a preferred teaching style. It is up to the classroom teacher to determine how they should teach.
"Our judgements on teaching are predicated on whether children are learning, progressing and achieving good outcomes.
"Since its inception Ofsted has always come under intense scrutiny and criticism because of the role we play.
"We will not be swayed from making tough judgements that lead to better outcomes for children."
Civitas's report comes just a few months after a row broke out after it was disclosed that two think tanks - Policy Exchange and Civitas - were examining the role of Ofsted.
Sir Michael hit out in the wake of the reports, saying he was ''spitting blood'' and accused Department for Education (DfE) staff of briefing against him
Then education secretary Michael Gove issued a statement voicing his full support for Sir Michael and the Ofsted boss later told MPs that in retrospect he made have made an error in speaking out before checking the facts, saying his comments were ''a spontaneous act of fury''.