Beaconsfield High School is the best secondary school in Buckinghamshire, new government league tables show.
But at the other end of the scale, The Buckingham School is ranked in the bottom five.
Beaconsfield High School replaces Sir William Borlase's Grammar School as the highest-ranking school in Buckinghamshire, after achieving a strong score in the Progress 8 measure, used to assess how much pupils have improved during their time at the school, for the 2017-18 academic year..
Dr Challoner's High School and Aylesbury High School also performed well.
At the other end of the scale, Buckinghamshire UTC was bottom of the progress score rankings for last year.
Beaconsfield High School, in Beaconsfield, is an academy converter which accepts girls aged 11 to 18.
It has 1,117 registered pupils. Of them, 108 were eligible to take GCSEs last year.
Pupils are measured across their scores in eight GCSEs, including core subjects (maths, English and sciences), and their best scores in other, chosen subjects.
These scores are compared to their performance in Key Stage 2 exams, and used to calculate the amount of value the school is adding to a child's education, measured by the institution's Progress 8 score.
In Beaconsfield High School, all of pupils hit the expected target, grade 4 to 9, in English and maths. In total, 97% hit strong grades of 5 or above in both subjects.
As a result, the school achieved a Progress 8 score of 1.21, the highest in Buckinghamshire. Scores of above and below zero are better and worse than average respectively.
The top schools in Buckinghamshire, according to their Progress 8 scores, were:
1) Beaconsfield High School (Progress 8 score: 1.21)
2) Dr Challoner's High School (1.14)
3) Aylesbury High School (0.98)
4) Chesham Grammar School (0.94)
5) Aylesbury Grammar School (0.91)
6) Dr Challoner's Grammar School (0.85)
7) Wycombe High School (0.76)
8) Sir William Borlase's Grammar School (0.74)
9) Waddesdon Church of England School (0.72)
10) Cressex Community School (0.68)
Meanwhile, at Buckinghamshire UTC, 45% of pupils hit the expected target, grade 4 to 9, in English and maths, and the school was awarded a Progress 8 score of -0.87.
The worst schools in Buckinghamshire, according to their average Progress 8 scores, were:
=31) The Misbourne School (-0.28)
=31) Buckingham School (-0.28)
=31) Bourne End Academy (-0.28)
34) The Grange School (-0.43)
35) The E-Act Burnham Park Academy (-0.57)
36) The Mandeville School (-0.74)
37) Buckinghamshire UTC (-0.87)