Level 2 Computer Science Report

COMMENTARY
91371

Candidates who clearly demonstrated understanding of basic concepts from computer science wrote in their own voice, providing evidence from their own work and experience to support any referenced material.

Candidates who simply reproduced information from sources such as Internet sites and teacher notes often did not demonstrate their own understanding.

Reports that reproduced supplied or sourced material without relating the identified knowledge to a specific context such as a digital device often did not demonstrate understanding.

The use of annotated photographic and diagrammatic evidence developed to demonstrate their understandings assisted candidates to achieve. Photographs and diagrams presented as evidence without specific annotation often did not demonstrate understanding.

In considering human computer interfaces, some candidates confused functionality of devices with usability. Some candidates did not refer to the usability heuristics.

Some reports followed the exemplar too closely with just minimal changes of the data. This practice did not contribute to an Achieved grade.

Candidates who produced well-formatted documents particularly well formatted code and screen shots were advantaged as this assisted the markers to establish clearly candidate understanding.

Candidates were disadvantaged where evidence for the standard was presented in a report longer than the specified 14 pages.

STANDARD REPORT
91371 Demonstrate understanding of advanced concepts from computer science

ACHIEVEMENT 
Candidates awarded Achievement commonly:
• described ways in which different types of data could be represented using bits, such as text, colour, audio, numbers and images
• described the concept of encoding information using compression coding and typical uses such as images and audio
• described the concept of encoding information using error control coding and typical uses such as parity and ISBN
• described the concept of encoding information using encryption and typical uses such as Caesar Cypher
• provided examples from human-computer interfaces, such as a chosen device, and described how they illustrated usability heuristics.

NOT ACHIEVED
Candidates awarded Not Achieved commonly:
• copied material verbatim from other sources (particularly the internet) and, in doing so, failed to show their own understanding
• copied material verbatim from other sources and did not differentiate between copied data and their own understanding
• described only one or two of the three required concepts
• lacked detail in their descriptions
• attempted to paraphrase without understanding
• described features in their chosen device but did not answer the questions in the standard
• used the allowed pages unnecessarily with cover sheets or extensive printouts of device specifications or tables of data from the Internet.

ACHIEVEMENT WITH MERIT 
Candidates awarded Achievement with Merit commonly:
• demonstrated in-depth understanding of advanced concepts from computer science
• compared and contrasted different ways in which different types of data could be represented using bits, such as ASCII and Unicode, and discussed the implications
• discussed how a widely used technology, such as ISBN, JPEG, or ZIP, was enabled by one or more of compression coding, error control coding, or encryption
• evaluated a given human-computer interface, such as a chosen device, in terms of usability heuristics
• used annotated photographic and diagrammatic evidence to demonstrate their understandings.

ACHIEVEMENT WITH EXCELLENCE 
Candidates awarded Achievement with Excellence commonly:
• demonstrated comprehensive understanding of advanced concepts from computer science
• articulated their understanding in their own words and from personal experience
• evaluated a widely used system for compression coding, error control coding, or encryption
• suggested a number of relevant improvements to a given human-computer interface based on an evaluation in terms of usability heuristics.