How five schools fared in the GCSE rankings
Lindsay Fergus takes a closer look at the stories behind some contrasting performances in the league tables
St Joseph's Grammar, Donaghmore: huge success story
This voluntary grammar school is a new entry at the top of the Belfast Telegraph league table after 100% of its pupils achieved five GCSEs including English and Maths at grades A* to C.
The 11-18 school is located in rural Tyrone in the village of Donaghmore, which is about 6km from Dungannon.
Its enrolment has steadily climbed over the last decade from just under 500 pupils to 635. Last year 152 pupils applied to the oversubscribed school, up from 112 in 2012 and 102 in 2011.
St Joseph's, which is headed by Enda Cullen, has also undergone a number of changes since the Millennium.
Founded over 90 years ago by the Daughters of the Cross, the Catholic all girls' school became co-educational in 2003. In 2010 it added an Irish Medium stream.
Although it has been seven years since the school was last inspected, St Joseph's has a consistent academic record and is renowned for its pastoral care.
In 2011/12 95.9% of pupils achieved five GCSEs including English and Maths at grades A* to C, meaning it is up 30 places in this year's league table.
This academic year the lowest grade it accepted from the GL Assessment was B1 up from C1 the previous year.
Last year the school received more than £2.5m in funding to spend on its day to day running costs.
St Michael's Grammar, Lurgan: steady progress after intervention plan
For the third year in a row -- since the Belfast Telegraph League Tables began -- St Michael's Grammar school has seen its results improve.
The percentage of pupils achieving five GCSEs including English and Maths at grades A* to C has risen from 86.9% in 2010/2011 to to 94.4% in 2012/13 -- up 14 places on last year.
The co-educational voluntary grammar school currently operates within the Dickson Plan and is a senior school, which pupils enter at age 14.
St Michael's was the first Catholic grammar school to be placed in the Department of Education's formal intervention Programme after being criticised by inspectors. It has been in formal intervention since April 2013.
However, the school, which has 582 pupils, is to merge with two non-grammar schools, St Paul's Junior High (ranked 204=) and St Mary's High, Lurgan (ranked 200) to create a new non-selective voluntary grammar school.
Education Minister John O'Dowd has also given the green light for a brand new school to be built.
Immaculate Conception College, Derry: under-threat site has fallen 49 places
With less than five of its pupils achieving five GCSEs including English and Maths at grades A* to C, Immaculate Conception College sits at the bottom of the league table along with two other schools.
It has fallen 49 places from last year when 29.5% of pupils attained that benchmark.
The co-educational Catholic maintained school has suffered from declining enrolment for years, down from 254 pupils in 2008/09 to less than 123 pupils.
The Council for Catholic Maintained Schools, which runs the school, has said it is unviable and has proposed its phased closure starting this September.
Immaculate Conception, formerly St Brecan's High, is the last Catholic post primary school in Derry's Waterside.
The school, where more than half the pupils come from a disadvantaged background and have special education needs, had a budget of just over £1m in the 2012/13 school year.
Lagan College, Belfast: GCSE results drop for third year in row
Although Lagan College continues to be one of the best performing integrated post primary schools -- fifth of 20 -- it has seen its GCSE results drop for the third consecutive year.
The all ability school, which admits up to 35% of its Year 8 intake using academic selection, now has less than half its pupils achieving five GCSEs including English and Maths at grades A* to C.
Last year 46.4% of pupils achieved that benchmark, down from 50.5% in 2011/12 and 50.8% in 2010/11.
Lagan College is a popular school and is oversubscribed every year despite having an intake of 200 Year 8 pupils.
The school, which started out with just 28 pupils in 1981, now has 1,260 pupils and last year received more than £5.2m in funding.
Education Minister John O'Dowd also officially opened a state-of-the-art brand new school in the Castlereagh Hills earlier this year.
Aughnacloy College is a small rural school located on the outskirts of the Tyrone village.
It has jumped 94 places in the league table to position 74 from 168 -- after more than doubling the percentage of pupils achieving five GCSEs including English and Maths at grades A* to C.
That makes it the seventh best performing non grammar in Northern Ireland, and Aughnacloy College also outperformed one grammar school.
In 2011/12 just 26.5% of pupils attained five good GCSEs, in 2012/13 that figure soared to 60.9%.
It is also a three-year high up from 45.2% in 2010/11, since the Belfast Telegraph League Table began.
Principal Colin Berry (above) said: "This is a tremendous achievement for Aughnacloy College.
"The staff and pupils have worked very hard and are very pleased to have been ranked as top non grammar school in Co Tyrone."
The 11-16 controlled school has maintained a steady enrolment but has just 169 pupils.
Last year there were only 24 Year 12 pupils.
Last April Aughnacloy College received a glowing inspection report, with inspectors rating the school as very good.
In the 2012/13 school year, its budget was just £834,092.