The cynical view is that school attainment is about catchment and chemistry. Catchment area determines a school's intake and, while schools can add value, they cannot escape the educational consequences of disadvantage.
Chemistry is more complex. The view here is that key staff changes can energise a school, but as the leaders are promoted and move on, a school will sink back to its previous level.
It is an analysis that Pat Reynolds understands, but doesn't accept. She is head of the Essex advisory service. After 20 years in teaching, including a headship in Northamptonshire, which she left only last summer, she is convinced that only half the analysis is correct.
"Chemistry and strong leadership can have a huge impact," she says. "The challenge for the LEA is to ensure that good practice is spread within the school and becomes a culture that pervades."
Along with most Ofsted inspectors and advisers, Reynolds cannot abide the suggestion that disadvantage equals failure.
"For heads in schools in challenging circumstances it can be difficult to raise your head from the day-to-day problems to see the bigger picture," she acknowledges. But the LEA's role is to understand those pressures while guiding heads towards solutions.
One obvious solution is the spreading of best practice. Sometimes this can be resented by heads, who see successful schools in middle-class areas being touted as models to follow. "What challenges have they faced?" heads might be heard to mutter. But it is not a question likely to be heard from anyone listening to Andy White.
He is head of Woodlands school in Basildon. In 1990, when he joined the school, it had experienced several years of decline. Results were poor, with only 10 per cent of pupils gaining five A to C grades in their GCSEs, and parents were abandoning the school in droves. It's now up to 1,450 pupils, with an A to C pass-rate of 40 per cent plus. "We anticipate something near 50 per cent this year," he says. "We want to push and move up from that."
And 92 per cent of Woodlands' pupils got four or more A to G grades.
"The stats show that we are doing well throughout the school," says Mr White. "Not just for an elite of A to C kids."
Professional development is at the heart of a lot of what the school has achieved. Tere are one-year research grants for staff. One teacher is running a gifted project: "She's researched what's on offer, then put together a programme to build on what we already do to enhance the experience of our gifted pupils."
Another teacher is researching numeracy and looking at how Woodlands compares nationally. Another pair have been to Belgium to look at design and technology. "Teaching isn't just about being in the classroom," argues White. "It's about learning."
One of the head's key issues is about moving Woodlands' students on to university. "We had four kids in 1990 who left us for higher education," he says. "Last year it was 80. We keep data on every pupil - we know what their potential is and we share that with the kids. And it's not just about target-setting, it's about supporting them in reaching those targets."
To encourage children to start with the right approach from day-one Woodlands runs a two-week summer school for the whole of the Year 7 intake. "Kids want to come in their holidays as long as the activities are focused and exciting," says White.
Some of those Year 7 come from Ghyllgrove primary school where Cath Power is headteacher. "When I arrived, the school was failing and a year later it had serious weaknesses," she says with feeling.
Power has taught in Essex all her career and came to Ghyllgrove after a deputy headship in nearby Thurrock. She is now in her fourth year and has seen results climb.
"Science went from 17 per cent to 85 per cent; English went from 32 per cent to 66 per cent; maths from 39 per cent to 69 per cent. In the beginning we worked primarily on behaviour."
Essex has a multi-disciplinary behaviour programme, which Ghyllgrove adopted. It involved whole-school training in strategies and the programme included everyone from the staff, to learning assistants and the midday assistants.
"Everybody in school was trained in the same strategies," says Power. "It was almost like waving a magic wand - the teachers saw that it worked and that maybe I was bringing something into the school to make their jobs easier."
"We've still got a way to go," she says, "but the challenge now is to retain what we have while improving it even further."
Neither Andy White nor Cath Power see the challenges facing their schools as any excuse for failure, and they both see the role of the authority as crucial in helping turn their schools around.