A Rickmansworth secondary school has gone from being "outstanding" to "good" since becoming an academy, its most recent Ofsted inspection report reveals.
Saint Joan of Arc Catholic School, in High Street, has been deemed "good" by inspectors from the education watchdog.
The secondary school, which teaches 1270 pupils, converted to an academy in March 2012.
When its predecessor school of the same name was last inspected by Ofsted, it was judged to be outstanding.
However, headteacher Peter Sweeney said he is "delighted" with the report and is not fazed at the school’s new rating, as the criteria against which Ofsted judges a school has changed since their last inspection.
Mr Sweeney said: "We were delighted with the report. The last time we were inspected was under a different framework.
"The Ofsted report confirmed that there is not a lot we have to do to move towards an outstanding.
"We always knew there were improvements that had to be made and you’re always looking to refine the processes in place and make sure that the pupils have the best opportunity to achieve their potential."
The Ofsted report was published on January 22 after inspectors visited the school on December 5 and 6 last year.
Inspectors highlighted that the school was not outstanding as "a very small amount of teaching still requires improvement", "teachers’ marking does not always show students clearly the next steps to improvement" and that "the teaching of science has not been as effective as the teaching in other subjects".
In order for the school to improve further, inspectors said that the quality of all teaching should be raised to good or outstanding and that the school should ensure that subject leaders consistently apply and monitor the school’s marking policy.
The school is assessed in four areas, which include the achievement of pupils, the quality of teaching, the behaviour and safety of pupils and leadership and management.
A good grading was awarded in every aspect apart from the behaviour and safety of pupils, which was considered to be outstanding.
The school’s previous inspection was on February 8 and 9, 2011, when it was considered to be "an outstanding school".
Speaking about the difference between the Ofsted reports, Mr Sweeney explained: "It’s very difficult to compare the criteria used to judge schools in 2013/14 with the same criteria a few years ago.
"Schools are finding more and more that they are required to improve under the new framework."