*** In 2026 this external will be an Online Examination held on TUESDAY 10th NOVEMBER - PM ***
This exam asks students to analyse a specific area of computer science. Students need to go beyond just describing the topic, they need to explain how it works, explore real-world examples, discuss its challenges, and evaluate its impact from different perspectives.
This is a chance to show not just what they know, but how well you can think critically about a complex computer science idea.
Every year, THREE topics are named in the NZQA Assessment Specifications for Teachers and Students to focus on. In the exam students choose to answer questions for ONE topic only.
In 2026 the THREE topics are: Complexity and tractability, Big data, Formal languages.
For Complexity and tractability, questions may cover: polynomial and non-polynomial time complexity, Big O notations O(1), O(log n), O(n) , O(n^k), O(2^n), O(n!), and best-case, worst-case, and average-case time complexity, complexity classes (P, NP, NP-complete), solving complex problems (approximation algorithms / heuristics), algorithm design and optimisation, optimal solutions (Travelling salesman / knapsack, etc.).
For Big data, questions may cover: characteristics of big data (volume, variety, velocity, etc.), generation, processing and analysing data in different formats, interpretation and representation (bias and display), tools and technologies used in big data, and big data considerations (privacy, ethics, and data governance).
For formal languages, questions may cover: regular expressions and their use in pattern matching and validation; simple finite-state automata and their role in recognising regular languages; context-free grammars (CFGs) and their applications in programming languages; and the relationship between formal languages, compilers, and computational complexity.
Special notes
Teachers are encouraged to help their students to develop answering techniques to ensure that they are able to respond clearly and concisely within the total recommended word limit of 1500 words.
Teachers are strongly encouraged to prepare students to be able to apply their understanding of computer science to unfamiliar contexts.
Teachers should prepare students to identify and articulate instances where overlap with various areas of computer science occurs, e.g. with artificial intelligence.
Further information about digital external assessment can be found on the NZQA website.