This document provides a brief introduction to teachers on the Computer Science Field Guide assessment guides for NCEA Achievement standard AS91074 (1.44).
1.44 has bullet points for the following three topics in computer science:
- Programming Languages
- Human Computer Interaction
Each of these topics has a chapter in the Computer Science Field Guide.
Currently, we provide two different assessment guides for algorithms (sorting and searching), and one for each of human computer interaction and programming languages. Note that students only need to follow one assessment guide for each of the three topics (i.e. they do not need to do both searching and sorting for the topic of algorithms).
The advice below applies to the whole standard; advice specific to each topic is available through the main NCEA index.
For the topic of algorithms, students can demonstrate their understanding of algorithms and their costs by using either sorting algorithms or searching algorithms.
For students who are weak at math, searching algorithms is probably the better choice. Sorting algorithms requires either being good at understanding trends from data in a table or understanding how to read trends from a graph in order to achieve merit or excellence, whereas the cost of searching algorithms can easily be seen by students carrying out the algorithms themselves.
Sorting algorithms provide a slightly richer range of possibilities, including more ways to demonstrate how they work in a student's report, and intriguing new approaches to a common and easily described task that may not have been obvious.
Guidance is given for achieved, merit, and excellence for both sorting algorithms and searching algorithms.
The three topics can be completed in any order, although the first bullet point in each level (comparing algorithms, programs, and informal instructions) is probably best left until both algorithms and programming languages have been completed, since those topics can provide examples to illustrate the points in the first bullet points.
Covering Human Computer Interaction first may make the Algorithms topic more relevant to students. In many cases, a not so good algorithm will take a second to run, whereas a better algorithm will take less than a tenth of a second. This is very significant in terms of a good user interface, so covering HCI first will make students more aware of issues like this.
In their report, it is important that the three topics are kept separate. Order does not matter, but the student should have three or four main headings (it is up to them whether or not they put the two parts of algorithms together), and keep all the material under the relevant headings. This will make it far easier for the marker to find the evidence they are looking for.
It is important that students use personalised examples to base their explanations around, and that the explanations are in their own words, and based on their example (rather than being a paraphrase from Wikipedia, for example).
Personalised means that the student’s example is different to their classmates. For example, they may have a program that prints their name or favourite saying, they may use a different number of items to sort or search through, their choice of the values being sorted or searched in examples is unique, and they may carry out their own usability exploration of a device they chose, and report on it in their own words.
If the teacher provides too many headings or leading questions for students to structure their work, this can reduce the opportunity for the report to reflect a personal understanding.
There is no reason for students to paraphrase Wikipedia in this achievement standard. All explanations should be based on their own examples.
It is important to note that the page limit given by NZQA is a limit - not a target. The markers prefer reports that are short and to the point. The requirements of the standard can easily be met within the limit.
The page limit for 1.44 is now 10 pages to cover the three topics. A possible breakdown that leaves one additional page is:
- Algorithms: 4 pages
- Programming Languages: 2 pages
- Human Computer Interaction: 3 pages
The assessment guides for the specific topics provide further guidance on how to stay within these limits. Students should be mindful of the recommended limits while they are working on their reports, in order to avoid having to delete work they put a lot of effort into.
Some hints to reduce total length and maximise readability:
- Only include what is relevant to the standard. While covering additional material in class is valuable for learning, additional content that doesn't demonstrate understanding of the topics and bullet points in the standard is only a distraction in the report.
- Resize screenshots and photos so that they are still readable, although don’t take up unnecessary space. Use cropping to show the relevant parts of the image.
- Don’t leave unnecessary space in the report. It both looks untidy and makes it more difficult for the marker to find what they are looking for.
- Use logical headings, and do not include a title page.
- A table of contents page is not necessary - your report should be organised in a way that the marker can easily find what they are looking for. For example, keep the three main sections (Algorithms, Programming Languages, and Human Computer Interaction) one after the other, and do not jump between them.
Students should regularly check over their report by trying to think of it from the marker's point of view. A common mistake is to put in graphs without labels on the axes, which can make it difficult for the marker to know what is being shown. Additionally make sure units are given for measurements (e.g. 5 seconds or 5 minutes?). If referring to colour in an image, don't print the report in black and white! Don't assume the marker will know anything about the instructions that were given in class. Good explanations of what was done and why are essential.
If using examples, don't use ones taken from the Field Guide or other sources - students should make up their own. For sorting and searching, they should actually carry out the balance scales activity using either the field guide interactives or physical balance scales. For HCI, students can choose an interface to evaluate themselves.
In 2012 we did a study that looked over 151 student submissions for 1.44 in 2011. This was the first year 1.44 was offered, although the lessons learnt are still relevant, particularly for teachers teaching the standard for the first time. A WIPSCE paper was written presenting our findings of how well students approached the standard and our recommendations for avoiding pitfalls. Our key findings are reflected in the teacher guides, although reading the entire paper would be worthwhile.
The paper was Bell, T., Newton, H., Andreae, P., & Robins, A. (2012). The introduction of Computer Science to NZ High Schools --- an analysis of student work. In M. Knobelsdorf & R. Romeike (Eds.), The 7th Workshop in Primary and Secondary Computing Education (WiPSCE 2012). Hamburg, Germany. The paper is available here.