Gerry McCormac has denied that cost- cutting drove his review of teachers' terms and conditions, insisting that the best interests of pupils are at the heart of all 34 recommendations.
MSPs this week grilled Professor McCormac and Isabelle Boyd, a member of his review group, on their most controversial recommendations in a bid to shed new light on the rationale behind them.
"This is not - as perhaps reported by some - an attack on the teaching profession," Professor McCormac told the Scottish Parliament's education and culture committee.
Some have interpreted the review's call for greater "flexibility" as a veiled excuse to increase teachers' workload. But Professor McCormac said the idea was to shift the focus onto pupil outcomes rather than "a list of dos and don'ts that can be prescriptive".
The removal from the existing agreement of annexes A and E - which specify the tasks a teacher should and should not do - was not an excuse to remove administrative and support staff, he added, pointing out that the review had praised their contribution.
And the idea of aggregating primary teachers' non-class contact time into larger blocks - rather than the standard 2.5 hours a week - was a response to a "fairly inflexible system", Professor McCormac said. Larger blocks of time would make it easier "to do something useful", he added.
On one of the most controversial proposals - bringing experts into the classroom without a teacher present - Mrs Boyd stressed this should not happen in an "ad hoc fashion". Teachers would be responsible for detailed planning of when and why experts were used.
Ending the chartered teacher scheme was justified, Professor McCormac said, in light of consistent evidence that, even after modification, the scheme was not having the desired impact on pupils' learning.
"Even some chartered teachers themselves said that the programme was quite academic and not classroom-based enough to have any clear evidence of making a difference," he said.
The review's proposal to encourage more temporary appointments to Point 1 of the principal teacher grade has prompted accusations that this was a ruse to create long-term temporary posts.
Mrs Boyd, headteacher at Cardinal Newman High in Bellshill, North Lanarkshire, denied this, saying it was happening already in some schools, where it led to "enhanced professionalism".
"It's not about having some kind of revolving way of preventing permanent posts from being filled," she added.
Professor McCormac clarified the review group's position on class sizes: it had found some evidence that smaller classes in the early years of school produced benefits. "Reducing class sizes is a laudable objective, there is no question about that," he said.
But in a time of economic turmoil, if it came to a choice between smaller classes and improving the quality of teachers, the priority had to be the latter.
The newly-formed Scottish Primary Teachers' Association (SPTA), in written evidence to the education committee, described the McCormac review's portrayal of chartered teachers as "repugnant".
Those who were reluctant to reveal their status had been depicted as "work-shy", the newly-formed union said; in fact, they did not want to be seen as "too big for their boots".
The idea that expert non-teachers could take classes on their own did not make sense, as it was a teacher who had the skill to "adjust, extend and evaluate" learning.
The SPTA was adamant that the removal of Annex E was a precursor to cutting support staff's jobs, and was "puzzled" by the review's failure to mention nursery teachers.