Latest Ofsted figures show that 37 of Lincolnshire’s 54 secondary schools are rated good or outstanding, as of October 31.
However, seven require improvement and 10 are inadequate, the worst rating for a school.
This means Lincolnshire now has one more secondary school which is inadequate or requiring improvement than compared with five years ago.
Ofsted, the schools regulator, inspects every new school within three years of opening.
Inspectors judge education providers on the effectiveness of their leadership, quality of teaching and learning, personal development and welfare, and the outcomes for learners.
If a school is rated as inadequate it will be re-inspected within 15 months, and between one and two years if it requires improvement.
Kevin Courtney, joint general secretary of the National Education Union, said there was a link between the level of school disadvantage and the outcome of Ofsted inspections.
He said: “A report from the Education Policy Institute found that schools with more disadvantaged pupils are less likely to be judged good or outstanding, while schools with low disadvantage and high prior attainment are much more likely to be rated highly.”
Mr Courtney said a high turnover of teachers, as well as struggles in recruiting specialist staff, contributed to this.
He added: “Naming and shaming schools and labelling them through negative Ofsted judgements is entirely the wrong approach.”
Out of the 360 schools in Lincolnshire, 18 per cent are rated as outstanding, which is above the East Midlands’ average, and 66 per cent are rated good.
Meanwhile, 22 schools are inadequate and 36 require improvement, which equates to 16 per cent
This is below the average for the East Midlands, which is 17 per cent.
Across England, 21 per cent of schools were classed as outstanding, 65 per cent as good, 11 per cent requiring improvement and three per cent as inadequate.
A Department for Education (DfE) spokesman said where pupils are not receiving a good education ‘we will not hesitate to take action, either through the offer of support or intervention, as appropriate’.
He continued: “There are 1.9 million more children in good and outstanding schools compared to 2010.
“This represents 86 per cent of children, compared to just 66 per cent in 2010.
“The number of schools that are rated inadequate or requires improvement has decreased since 2010, going down from 32 per cent to 14 per cent in March of this year.”
Ofsted said it would like to inspect schools rated as outstanding, which are exempt from routine inspections unless there is a specific concern about performance.
A spokesman explained: “Some schools have now gone for 10 years or more without being inspected, leaving us with a blind spot about the quality of education they offer.
“We have been clear that we would like this exemption to be removed, and have asked the DfE to look at the policy again.
“We focus our resources where they can have the greatest impact, so schools with lower grades are inspected more frequently.”