How many inspectors does it take to improve a nation's schools - a thousand, a hundred? Or none at all?
The Canadian province of Ontario has driven attainment up in its 5,000 public schools without employing a single schools inspector, according to Avis Glaze, its education commissioner.
Speaking in Stirling to an international seminar on leadership, organised by Learning and Teaching Scotland, Dr Glaze said: "We don't believe in the big stick approach. We respect our professionals. We ask what professional development they need. We go into schools and work with them in a humane way. They respond to that. We get results."
Ontario's improvement strategy for schools is dubbed: "Results Without Rancour or Ranking."
Dr Glaze refused to be drawn on whether Scotland needed an inspectorate but said that "our whole philosophy negates the notion of inspection".
She added: "I've seen shame and blame cultures in some countries if schools are not doing well. They don't work. You get people leaving the profession in droves."
Dr Glaze described the alternative approach as one of "professional accountability rather than external accountability". She believed there could be accountability without inspection. "In Ontario, we don't tolerate incompetence or lack of improvement. But we've put that accountability on to the professionals in the school districts - your education authorities - to determine and report on their schools' effectiveness."
At province level, low-performing schools are identified and teams of professionals sent out to work with them. "It is about building capacity rather than inspection," she said. "This is not a naive approach. Staying as a poor, low-performing school is not an option.
"We are interested in improvement, rather than where schools are at any given time. Schools in leafy suburbs often do well, but don't improve."
Parents' views were a key component in transformation, Dr Glaze emphasised. "You get them on board by raising attainment in schools as fast as you can," she said. "Then you can work on the whole child, on emotional intelligence, character, critical thinking skills.
"Teachers don't get up in the morning thinking they want to do a bad job. We need to have faith in our teachers."