specification overview
OCR A-Level Computer Science (H446) is a two-year linear qualification split between two written papers and a programming project. Component 01 (Computer Systems) is worth 40%, Component 02 (Algorithms and Programming) is worth 40%, and Component 03/04 (the Programming Project, non-exam assessment) is worth 20%.
subject content
1.1. The characteristics of contemporary processors, input, output and storage devices
Component 01- CPU architecture, fetch-decode-execute cycle
- Memory, storage and I/O devices
1.2. Software and software development
Component 01- Types of software; systems software; applications software
- Programming paradigms and software development methodologies
1.3. Exchanging data
Component 01- Compression, encryption and hashing
- Databases, SQL and normalisation
- Networks, protocols and the internet
1.4. Data types, data structures and algorithms
Component 01- Primitive and composite data types
- Data structures (arrays, linked lists, trees, stacks, queues, hash tables)
- Boolean algebra and logic gates
1.5. Legal, moral, cultural and ethical issues
Component 01- Computing legislation and privacy
- Ethical issues in computing
2.1. Elements of computational thinking
Component 02- Abstraction, decomposition, pattern recognition and algorithms
- Thinking procedurally, logically, concurrently and abstractly
2.2. Problem solving and programming
Component 02- Programming techniques and structured problem-solving
- Software development lifecycle
2.3. Algorithms
Component 02- Algorithm analysis (Big-O)
- Standard algorithms (searching, sorting, graph traversal, path-finding)
assessment structure
| Paper | What's assessed | Length | Marks | Weight | Question types |
|---|---|---|---|---|---|
| Component 01 (Computer systems) | Topics 1.1-1.5: architecture, software, exchanging data, data structures, ethics | 2h 30m | 140 | 40% | Short-answer, structured and extended-response questions |
| Component 02 (Algorithms and programming) | Topics 2.1-2.3: computational thinking, problem-solving, algorithms | 2h 30m | 140 | 40% | Short-answer, structured and extended-response questions including algorithm and code writing |
| Component 03/04 (Programming project) | Non-exam assessment: a student-chosen practical programming project | Coursework | 70 | 20% | Analysis, design, development, testing and evaluation of a substantial programming project |
The Programming Project (Component 03 or 04) is a substantial NEA worth 20% of the A-Level. The two components are the same assessment and differ only in the moderation route: H446/03 is work uploaded electronically (OCR Repository / Submit for Assessment), while H446/04 is a sample posted to the moderator. Language choice is identical either way.
assessment objectives
| AO | What it means | Overall |
|---|---|---|
| AO1 | Demonstrate knowledge and understanding of the principles and concepts of computer science, including abstraction, logic, algorithms and data representation. | 35% |
| AO2 | Apply knowledge and understanding of the principles and concepts of computer science including to analyse problems in computational terms. | 30% |
| AO3 | Design, program and evaluate computer systems that solve problems, making reasoned judgements about these and presenting conclusions. | 35% |
key tips for success
Start the programming project early
The NEA is 20% and needs substantial development time. Start scoping the problem in year 12 rather than leaving it for year 13.
Master Big-O analysis
Component 02 tests algorithm analysis. Practise deriving Big-O for common algorithms (bubble sort, quicksort, mergesort, binary search, graph traversal, path-finding).
Learn standard algorithms cold
Searching (linear, binary), sorting (bubble, insertion, merge, quick), graph traversal (BFS, DFS), path-finding (Dijkstra, A*). Know how to trace and code each.
Practise database and SQL
Component 01 tests relational databases through to 3NF. Practise writing SQL SELECT/JOIN/GROUP BY queries and normalising unstructured tables.
Know the TCP/IP stack
Application, transport, network, link layers. Understand which protocols sit at each layer (HTTP, TCP, IP, Ethernet). Consistently examined on Component 01.
Understand programming paradigms
Procedural, object-oriented, functional, declarative. Understand differences, when each is appropriate and how to identify them in unfamiliar code.
Where to next
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