Education chiefs in St Helens say they were unable to collect overall GCSE A* to C grades following a shift in recording attainment.
Town hall chiefs instead revealed a new measurement - called Attainment 8 - which increased from the 2015 figures.
Nationwide, attainment of five A* to C grades has fallen.
A spokesman for St Helens Council said: “We were not able to collect the overall figure of A*-C GCSE results from all nine of our state-funded schools.
“In addition, this metric has been replaced by the Attainment 8 measure for the purpose of recording attainment at the end of Key Stage 4 in 2016.
“In 2013, the government announced that a new secondary school accountability system would be implemented from 2016. It includes two new headline measures, Attainment 8 and Progress 8.
“The new performance measures are designed to encourage schools to offer a broad and balanced curriculum with a focus on an academic core at KS4, and reward schools for the teaching of all their pupils, measuring performance across 8
“In such circumstances, schools revised their provision to meet the demands of that change to a more academic curriculum, and the move away from 5ACEM from 2016.”