Do Leaving Cert Questions Repeat?

The short answer is that the wording almost never repeats and the topics almost always do. That gap is the reason past papers are worth your time. It is also the reason nothing in the record supports a predicted paper.

The numbers below come from our own copy of the Leaving Cert papers, held as structured data so the questions can be counted and compared. Every count states the papers it was measured over, and every question quoted links to the page of the official PDF it came from.

Whole questions do not come back word for word

Take the eleven Higher Level Biology papers from 2015 to 2025. Between them they hold 175 questions. We compared every pair of questions that came from different years, which is 13,915 pairs, and measured how much of their vocabulary they share.

The closest pair shares 52% of its words, and only two of the 13,915 pairs share more than half. So a whole question coming back untouched is not something the record shows.

Parts of questions are a different matter, and the two closest pairs are the ones to look at. Both are the Section A short-answer question, worth 20 marks, and both are on lipids. Here are four of the six parts from 2021 beside four of the six from 2024:

The other two parts differ in each year, so the questions are not the same question. The same facts are being asked for in different words.

That holds for long questions too. The 2015 Higher Level Biology paper opened question 10 with "Which famous 19th century biologist is regarded as 'the father of genetics'?" (2015 paper, page 9). The 2023 paper opened question 13 with "Which famous scientist is regarded as the father of genetics?" (2023 paper, page 4). Both then asked for the Law of Segregation. In 2023 those two parts carried nine marks between them; in 2015 the same nine-mark bracket also covered a third part on sex linkage.

Topics come back nearly every year

Our copy of the corpus groups each question under the strands of the subject syllabus, so we can count how many of the eleven Higher Level Biology papers touched each strand.

A question often covers more than one strand, so the question counts add up to more than 175.

Genetics appeared in 11 of the 11 Higher Level Biology papers since 2015, across 27 questions. The thinnest strand in the table, human reproduction, still appeared in 8 of the 11.

Higher Level Maths looks the same. Across the 22 Higher Level papers from 2015 to 2025 (papers 1 and 2 in each of the eleven years) there are 208 questions. Calculus appeared in all eleven years, in 70 of those 208 questions. Complex numbers also appeared in all eleven years, in 12 questions. Financial maths appeared in 6 of the eleven years, in 6 questions.

Recurrence is uneven, and a table like this is what shows you where. A strand that has appeared in every paper and a strand that has appeared in six of eleven are both worth revising, and they are not worth the same amount of time.

The same skill, asked two ways

Topic recurrence on its own would still leave you guessing about form. The pattern that helps more is that the structure of a question recurs while the surface of it changes.

Higher Level Maths, paper 1, question 4, in two different years:

Prove by induction that $8^n - 1$ is divisible by $7$ for all $n \in \mathbb{N}$. (2016, paper 1, page 6, 25 marks)

Prove using induction that $2^{3n-1} + 3$ is divisible by $7$ for all $n \in \mathbb{N}$. (2021, paper 1, page 10, 30 marks)

The expression changed. The method did not. Write out the 2016 proof, mark it against the scheme, and work out why the inductive step holds, and the 2021 question asks you for nothing further. A proof by induction was asked in 6 of the eleven Higher Level Maths years since 2015 (2016, 2018, 2019, 2020, 2021 and 2025).

Biology does the same across question types. In 2016, sex linkage came up as a 20-mark Section A question:

(b) (i) In genetics, what is meant by the term sex-linkage? (ii) Would human females or human males be more likely to suffer from sex-linked diseases such as haemophilia? (iii) Explain your answer to part (ii) by referring below to possible genotypes and their corresponding phenotypes. (2016, page 4)

In 2023 the same content came up inside a 60-mark Section C question, wrapped around a pedigree chart:

(c) Haemophilia is caused by a recessive allele (gene mutation) that inhibits the blood's ability to clot. This allele is only found on the X chromosome... (iii) The pedigree chart above shows that two of their male children (persons 4 and 6) suffer from haemophilia. Show, using a Punnett square or otherwise, how it is possible for the parents to have a male child who does not suffer from haemophilia. (2023, page 4)

One asks you to state the genotypes. The other hands you a family tree and asks you to work from it. Underneath, both need you to write X-linked genotypes correctly and read a cross. Practise from the 2016 wording alone and you can arrive at the 2023 question knowing the biology and meeting the layout for the first time.

Recurrence is history, and prediction is not

Everything above is a record of what has already been examined. It says nothing about June.

The State Examinations Commission has been direct about this. In a statement reported by the Irish Examiner on Tuesday 26 May 2026, the SEC said that candidates "should be wary of all sources which claim to have knowledge of an examination paper in advance of it being given to candidates on the day of an examination", and that claims about predictions "should be considered spurious whether generated through AI systems or otherwise" (Irish Examiner, 26 May 2026).

A predicted paper narrows what you study on someone's guess, and the cost of the guess being wrong falls on you in the exam hall. Frequency data works the other way, because it tells you which parts of the course have historically carried marks while you still cover the course.

Genetics appearing in all eleven papers since 2015 does not tell you whether it will be a long question or a short one next June. It does not tell you which of its parts will be asked either. The corpus can tell you a topic recurs. It cannot tell you the form it will take, so the safe use of it is to practise the forms it has already taken.

What to do with this

Work topic by topic rather than paper by paper, at least once you have sat a full paper under timed conditions. The method is in our guide on how to study with past papers, and the short version is that you attempt, mark against the official scheme, and record what cost you marks.

The topic pages do the grouping for you. Genetics, DNA and evolution in Leaving Cert Biology lists the genetics questions from every year we hold, with the marking scheme beside each one, and sequences and series in Leaving Cert Maths does the same for the strand the induction proofs sit in. Answer one topic across several years in a row and the shared structure is hard to miss, because the fourth question in a row reads as a variation on the first three.

FAQ

Do Leaving Cert questions repeat? Not word for word. Across the eleven Higher Level Biology papers from 2015 to 2025, no two questions from different years share more than 52% of their wording. Topics and question structures repeat heavily, and that is what makes past papers useful.

Is it worth doing past papers if the questions change? Yes, because what you practise is the skill and the format, and both carry over. The 2016 and 2021 Higher Level Maths papers both asked for a proof by induction that an expression is divisible by 7, with a different expression each time.

Are predicted papers reliable? The State Examinations Commission has said candidates should be wary of any source claiming advance knowledge of a paper, and that prediction claims should be treated as spurious. Past-paper frequency is a record of what has been asked, which is a different thing.

How many years of past papers should I do for one topic? There is no established number. Working through the same topic across several consecutive years is what shows you the range of forms it has been asked in, and our topic pages hold every year we have for that strand.

The Leaving Cert topic pages group the past questions by topic, with the marking scheme beside each one, so you can take one topic across several years in a sitting. They are free and they link straight to the official SEC PDFs.