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Evaluation

Lesson 12 of 13 Approx 1 hr (single period)

Learning intentions

  • Understand the difference between testing and evaluation
  • Know the two WDD evaluation criteria: fitness for purpose and usability
  • Understand how audience characteristics, end-user tasks, and functional requirements are used when evaluating fitness for purpose
  • Be able to write an evaluation comment using a judgement supported by evidence and reasoning

Success criteria

  • I can explain the difference between testing and evaluation
  • I can name and describe fitness for purpose and usability
  • I can use evidence about navigation, consistency, interface clarity, readable content, and accessibility to evaluate usability
  • I can write a supported evaluation of a finished website against both criteria
Warm up — what do you already know?

Answer before the lesson begins.

1. What is the purpose of evaluation in web development?

2. Which feature is the clearest evidence that a website is usable?

3. Which evaluation criterion checks whether the original end-user requirements have been met?

Key vocabulary

evaluation
The process of judging the quality of the finished website against its original requirements and the needs of its target audience.
fitness for purpose
Whether the finished site suits the intended audience, lets users complete the required tasks, and provides the specified functions.
usability
How easily the target audience can navigate, understand, and operate the finished website.
audience characteristics
WHO will use the website, including age, skill level, accessibility needs, and access device.
end-user requirements
WHAT users need or expect to do on the website, such as finding information or contacting an organisation.
functional requirements
HOW the website will support the user tasks: the features and functions it must provide, such as linked pages, navigation, images, audio, or video.

Evaluation

Testing vs evaluation

Testing finds errors during development — broken links, missing images, browser compatibility issues. It gives a pass or fail result for each test.

Evaluation is different. It judges the quality of the completed website. Instead of asking whether one test passed, it asks how well the finished site meets its original requirements and how easy it is for the intended audience to use.

A site can pass its individual tests and still receive a weak evaluation. For example, every hyperlink might work, but users may still struggle because the navigation labels are unclear. Test results can provide useful evidence, but testing and evaluation are not the same process.

The two WDD evaluation criteria

Evaluate a finished website using fitness for purpose and usability. These two criteria focus on the product experienced by its end users:

F
Fitness for purpose
"Does the finished site meet the original requirements and audience needs?"
U
Usability
"Can the target audience navigate, understand, and operate the site easily?"

Fitness for purpose

Fitness for purpose compares the finished site with the analysis completed before development. Keep the three parts of that analysis distinct:

  • Audience characteristics — WHO: Does the design suit the users' age, skill level, accessibility needs, and access devices?
  • End-user requirements — WHAT: Can users complete the tasks identified in the scenario, such as finding opening times, viewing events, or contacting the organisation?
  • Functional requirements — HOW: Does the site include the pages, navigation, hyperlinks, images, audio, video, or other specified features that support those tasks?

A website may meet some requirements but not others, so a judgement can be positive, negative, or partial. Suppose a restaurant brief requires adults using smartphones to view the menu and find contact details. If both pages exist but the layout is unusable on a phone, the site only partially meets fitness for purpose: the content is present, but the access-device needs of the audience are not met.

Usability

Usability asks whether the target audience can use the finished website easily and successfully. It is about the user's experience of the interface, rather than the quality of the underlying source code. Useful evidence can come from several related aspects of the site:

  • Navigation clarity: links use meaningful labels, important pages are easy to reach, and users can tell where they are.
  • Consistency: navigation, colours, fonts, and layouts behave predictably across pages.
  • Interface clarity: buttons and controls look interactive, instructions are clear, and labels explain what will happen.
  • Readable content: text size, contrast, spacing, and language are suitable for the audience.
  • Accessibility: content works for the audience's accessibility needs, for example meaningful alternative text for informative images and controls that do not rely on colour alone.

These are sub-considerations within usability, not five extra evaluation criteria. Select the evidence that is relevant to the scenario. For example, a consistent menu may support a positive usability judgement, while tiny low-contrast text may support a negative one.

How the criteria can overlap

One feature can provide evidence for both criteria, but the reasoning changes. If a brief specifically requires a site for users with sight impairments, missing alternative text means the site does not fully meet that original audience requirement, so it affects fitness for purpose. The same missing alternative text also makes information harder or impossible for screen-reader users to access, so it is evidence of poor usability.

Always connect the evidence to the criterion you are judging. Do not simply list a feature such as "large text" or "navigation bar" without explaining its effect on the requirements or the target user's experience.

How to write an evaluation comment

Make a clear judgement, then support it with specific evidence and reasoning:

"The site [meets / partially meets / does not meet] [criterion] because [specific evidence], which means [effect on the requirements or target users]. [Relevant improvement, if needed.]"

For example: "The site does not fully meet fitness for purpose because the events page required in the brief is missing, so users cannot complete the task of finding upcoming events. The page should be added and linked from the main navigation."

The number of separate points needed depends on the question and its mark allocation. Read both carefully: a well-supported judgement is the goal, but there is no single mark formula that applies to every evaluation question.

Worked examples

Example 1 — Evaluating fitness for purpose

Brief: A restaurant site for adult commuters using smartphones. Users need to view the menu and find contact details. The site must provide Menu and Contact pages and mobile-friendly navigation.

Finished site: Both pages and their content are present, but the navigation disappears on a narrow phone screen.

1
Identify the criterion: compare the completed site with the audience characteristics, end-user tasks, and functional requirements, so use fitness for purpose.
2
Locate the evidence: the Menu and Contact pages let users complete both stated tasks, but smartphone users cannot reach them through the navigation.
3
Form a judgement: some requirements are met, but the access-device need and mobile-navigation requirement are not, so the site only partially meets the criterion.
4
Write the evaluation: "The site partially meets fitness for purpose because the Menu and Contact pages support both end-user tasks, but the navigation disappears on smartphones, the audience's stated access device. The mobile navigation should remain visible and operable on narrow screens."
Example 2 — Evaluating usability

Scenario: A health-centre website is mainly for older adults. Its navigation stays in the same place on every page and uses clear labels such as "Appointments" and "Opening times". However, body text is 11px light grey on white, and appointment controls are shown only as unexplained icons.

1
Identify the criterion: the question is about how easily the target audience can navigate, understand, and operate the interface, so use usability.
2
Locate the evidence: consistent, descriptive navigation helps users, but the small low-contrast text and unexplained icons make content and controls difficult to understand.
3
Form a judgement: the site has one strong usability feature but important barriers for its older target audience, so it is only partially usable.
4
Write the evaluation: "The site only partially meets usability because its consistent, clearly labelled navigation helps users find pages, but 11px low-contrast text is difficult for older adults to read and unexplained icons make the appointment controls unclear. The text should be larger with stronger contrast, and each icon should have a visible label."
Example 3 — Evaluating both criteria

Brief: A youth theatre site for teenagers, including keyboard users and users of screen readers. Users need to find performance dates and audition contact details. The site must provide Performances and Auditions pages.

Finished site: Both pages and the audition contact details are present. The same clearly labelled navigation appears on every page. Performance posters contain dates as images with no alternative text, and keyboard focus is difficult to see.

1
Identify the applicable criteria: the original tasks and features require fitness-for-purpose evaluation; ease of navigation and accessibility require usability evaluation.
2
Locate the evidence: the required pages and audition contact details are present, but screen-reader users cannot obtain the poster dates and keyboard users cannot easily see which link is selected.
3
Form the judgements: the site only partially meets fitness for purpose because one specified audience group cannot complete the performance-date task. Its consistent labels help usability, but the accessibility barriers prevent a fully positive usability judgement.
4
Write the evaluation: "The site partially meets fitness for purpose: the required pages and audition contact details are present, but missing text alternatives prevent screen-reader users in the target audience from finding performance dates. The site also only partially meets usability: navigation labels are clear and consistent, but missing alternative text and an unclear keyboard focus indicator make the site difficult to understand and operate for some intended users. Add equivalent text for the poster dates and a visible focus style."
Now you try

Site description: A local library website is intended mainly for older residents using tablets. Users need to find opening times and upcoming events. Both pages are present. Each page uses the same clearly labelled navigation, but the event descriptions use small pale-grey text and the buttons are labelled only with symbols.

Write a short evaluation against both fitness for purpose and usability. Give a judgement supported by evidence and reasoning for each criterion.

Fitness for purpose: The site meets the stated end-user tasks and functional requirements because the Opening Times and Events pages are both present, allowing residents to find the required information. However, its suitability for the older target audience could be improved because the event text is small and low contrast.

Usability: The site only partially meets usability. Consistent, clearly labelled navigation helps users move between pages, but small pale-grey event text is difficult for older residents to read and symbol-only buttons do not make their actions clear. The text should be enlarged with stronger contrast and the buttons should have visible text labels.

The response links each judgement to evidence and explains its effect on the requirements or target audience.

Common mistakes
✕
Confusing testing with evaluation. Testing checks individual features and records expected versus actual results. Evaluation judges the quality of the completed website against fitness for purpose and usability, using relevant evidence.
✕
Treating usability details as unrelated criteria. Navigation clarity, consistency, interface clarity, readable content, and accessibility are evidence used to judge usability. They are not five separate evaluation criteria.
✕
Blurring WHO, WHAT, and HOW. Audience characteristics describe who will use the site; end-user requirements describe the tasks they need to complete; functional requirements describe the features that support those tasks. Fitness-for-purpose evaluation checks all three without treating them as the same thing.
✕
Giving an unsupported judgement. A statement such as "the site is usable" is too vague. Support the judgement with evidence and explain its effect, such as: "The site is easy to navigate because every page uses the same clearly labelled menu, so users can predict where each link will be." Check the question's mark allocation to decide how many separate points are required.
Exam tip

For WDD evaluation, structure your thinking around fitness for purpose and usability. Use the criterion named in the question, make a clear judgement, and support it with evidence from the brief, finished site, or test results.

Explain why the evidence matters: connect it to an original requirement or to the target audience's ability to navigate, understand, and operate the site. If the site does not fully meet a criterion, a relevant improvement can make your reasoning clearer.

Always check the actual mark allocation and wording to decide how many separate evaluated points are needed. Do not assume that every question uses the same marks pattern.

Task Set

Questions 1–3 are auto-checked. Questions 4–8 are self-marked — write your answer, then reveal the model answer to check your work.

1. Which evaluation criterion judges whether the original end-user requirements have been met? TYPE 1

2. Which observation is evidence that a website has good usability? TYPE 1

3. What is the key difference between testing and evaluation? TYPE 1

4. Write two questions a developer could ask when evaluating fitness for purpose and two questions they could ask when evaluating usability. (4 marks) TYPE 2

Fitness for purpose:
• "Can users complete the end-user tasks identified in the analysis?"
• "Does the site provide the functional requirements and suit the stated audience characteristics?"

Usability:
• "Can the target audience find important pages through clear, consistent navigation?"
• "Are the interface, content, and accessibility features easy for the target audience to understand and operate?"

5. A website's eight pages were styled separately. Some pages use 12px pale-grey paragraph text, others use 18px black text, and the navigation changes position and colour from page to page. Evaluate the site's usability. (2 marks) TYPE 2

The site has poor usability because its text styling and navigation are inconsistent across pages. Users must repeatedly work out where the navigation has moved, and the 12px pale-grey text may be difficult to read. Using a consistent navigation position and a readable text style across every page would make the interface more predictable and easier to use.

6. A museum website presents its opening times only in an image with no alternative text. Evaluate the usability of this design for visitors who use screen readers. (2 marks) TYPE 2

The site does not meet usability for visitors who use screen readers because the opening times are available only inside an image with no text alternative. Those users cannot access this important information. The opening times should be provided as real page text, with suitable alternative text for any informative image.

7. Original requirement: "the site must be suitable for primary school children." The finished site uses 8pt text and includes the phrase "this is an expository summary of our extracurricular activities." Write an evaluation comment for fitness for purpose. (2 marks) TYPE 2

The site does not meet fitness for purpose because its design does not suit the stated audience characteristics. The 8pt text is too small and the complex phrase is unlikely to be understood easily by primary school children. Larger text and age-appropriate language would better meet the audience requirement.

8. Evaluate the following website against fitness for purpose and usability. Support each judgement with relevant evidence and reasoning. (4 marks) TYPE 2

Site description: A local library website is intended for adults and older residents using computers and tablets. Users need to find opening times, view upcoming events, and search the catalogue. The brief requires an Opening Times page, an Events page, a catalogue-search link, and clear navigation. All required pages, the link, and the navigation are present. The same labelled navigation appears at the top of every page. However, the Events page uses small low-contrast text, two informative event images have no alternative text, and the search link is labelled only "Click here".

Fitness for purpose: The site largely meets fitness for purpose because the Opening Times page, Events page, and catalogue-search link provide the specified functional requirements and allow users to attempt all three end-user tasks. However, it does not fully suit the audience characteristics because small low-contrast event text may be difficult for older residents to read.

Usability: The site only partially meets usability. Consistent labelled navigation helps users predict how to move between pages, but the low-contrast text reduces readability, missing alternative text prevents some users from understanding the event images, and "Click here" does not clearly explain that the link opens the catalogue search. Larger high-contrast text, useful alternative text, and a descriptive link label such as "Search the library catalogue" would make the site easier to understand and operate.
Teacher notes — Shift+T to hide

Suggested timing: 1-hour single period. This is a concept-heavy lesson with relatively little new technical content — it consolidates prior learning and frames it as quality judgements.

Opening: Put the headings "fitness for purpose" and "usability" on the board. Ask all pupils to sort sample observations such as "missing required page", "consistent navigation", and "small low-contrast text" under the most relevant heading, then discuss where evidence can support both criteria for different reasons.

Reconnect to WDD1: Reinforce the three-column distinction: WHO = audience characteristics; WHAT = end-user tasks; HOW = functional requirements and design decisions. Fitness for purpose compares the finished site with all three, but they should not be merged into one definition.

Model Q8 as a class: Read the site description together. For each criterion, identify relevant evidence, form a judgement, and explain the effect on the requirements or target audience before writing the evaluation sentence. Then let all pupils complete their own response.

Common error to address: Pupils may say "the site is good" without evidence, or list navigation, readability, and accessibility as separate evaluation criteria. Model how those details support a usability judgement. Remind pupils to use the wording and mark allocation of the actual question rather than relying on a fixed marks recipe.

Unit distinction: Fitness for purpose and usability are the WDD evaluation criteria for the finished website. Do not import SDD's code-quality evaluation framework into this lesson.