Commit ef4237

2026-04-25 22:18:29 lisa: Add C02 wiki content (DRAFT) — landing page, key-concept pages, Resources Builds out C02 (Data Collection & Analytical Diagrams). Adds C02-home, 3 new key-concept pages (DRAFT for teacher review tomorrow), external resource rows in C02-Resources.md, and a Hub link to C02-home. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

/dev/null .. sd/C02/C02-home.md
@@ 0,0 1,23 @@
+	# C02 — Data Collection & Analytical Diagrams
+
+	Hamilton College · Year 12 · 2026
+
+	The second SAT checkpoint covers how you gather evidence about your client's needs and how you model the system you are about to build. You will collect data from real people, prepare it for analysis, and produce three analytical diagrams — all under timed, hand-drawn conditions.
+
+	---
+
+	## Key concepts
+
+	Short explainers for the concepts most commonly confused or under-done at each rubric band:
+
+	- [Context Diagram vs Data Flow Diagram](/sd/C02/Context%20Diagram%20vs%20Data%20Flow%20Diagram) — what can appear on each diagram, side-by-side; the most common notation errors in C2-2
+	- [What Is an Entity?](/sd/C02/What%20Is%20an%20Entity) — why entities include external systems (APIs, email servers) as well as human users; how to find every entity from your user stories
+	- [Explaining vs Describing Your Data Collection](/sd/C02/Explaining%20vs%20Describing%20Your%20Data%20Collection) — the exact rubric difference between 7–8 and 9–10 for Indicator 1; worked examples of each level
+
+	## Resources
+
+	- [C02 Resources](/sd/Resources/C02-Resources) — per-topic reading and videos, including external resources for use case diagrams, qualitative vs quantitative data, and «include» vs «extend»
+
+	---
+
+	← Back to [VCE Software Development Hub](/sd/VCE%20Software%20Development%20Hub)
/dev/null .. sd/C02/Context Diagram vs Data Flow Diagram.md
@@ 0,0 1,76 @@
+	> **DRAFT** — under teacher review.
+
+	# Context Diagram vs Data Flow Diagram — What Goes Where
+
+	Hamilton College · Year 12 · 2026
+
+	One of the most common errors in C2-2 is treating these two diagrams as interchangeable — or producing a second context diagram and calling it a DFD. They are different levels of the same model, and each has strict rules about what can appear on it.
+
+	---
+
+	## Watch first (≈8 min)
+
+	{{Video|src=https://www.youtube.com/watch?v=XeJs9sYAuMg}}
+
+	*NSW Software Engineering — covers context diagrams and dataflow diagrams side by side using the same worked example. The notation conventions align closely with VCE.*
+
+	---
+
+	## Side-by-side: the two diagrams compared
+
+	| Feature | Context Diagram (Level 0) | Level-1 DFD |
+	|---|---|---|
+	| **How many system shapes?** | Exactly **one circle** — the whole system | **3–6 circles** — one per major process |
+	| **System shapes labelled as** | Your system's name (e.g. "Study Planner") | Numbered verb-noun phrases (e.g. "1. Verify Login") |
+	| **Internal processes shown?** | **No** — this is the most common mistake | **Yes** — that is the whole point of Level 1 |
+	| **Data stores shown?** | **No** | **Yes** — two parallel lines, named |
+	| **External entities** | Yes — rectangles outside the system circle | Yes — same entities as the context diagram |
+	| **Data flow labels** | Specific (e.g. "login credentials") | Specific — must be consistent with context diagram |
+	| **Entity ↔ Entity flows?** | Never | Never |
+	| **Entity ↔ Data store flows?** | N/A | Never — all flows go through a process |
+
+	---
+
+	## The most common mistakes
+
+	### On the context diagram
+
+	- **Showing internal processes** (e.g. drawing "Verify User" or "Save Data" as separate circles). If you have more than one circle, you have drawn a DFD, not a context diagram.
+	- **Showing a data store** (the double-line rectangle). Data stores do not exist at context-diagram level — the whole system is one black box.
+	- **Connecting entities to each other** with arrows. Every arrow must touch the system circle.
+
+	### On the Level-1 DFD
+
+	- **Drawing only one process circle** — that is a context diagram in disguise. Decompose the system into its major functions (3–6 processes).
+	- **Missing data stores** — if your software saves anything (user accounts, records, preferences), you need at least one data store.
+	- **Inconsistent entities** — your DFD entities must be identical names and roles to your context diagram entities. Divergence is a rubric error.
+	- **A process with only inputs and no outputs** (or only outputs) — a process that transforms nothing is not a process.
+
+	---
+
+	## A mental check before you submit
+
+	Ask yourself for each diagram:
+
+	**Context diagram:** "If I covered the label on the system circle, would a reader know this is one system, not a set of functions?" If you have multiple circles, it fails this check.
+
+	**DFD:** "Can I trace a path — from an external entity, through at least two processes and one data store, to an output?" If not, your decomposition is incomplete.
+
+	---
+
+	## Why VCAA cares
+
+	The C2-2 rubric at **3–4** requires *"illustrates the features of the context diagram/s"*. The marker is checking: one system circle, correct entities, labelled flows. Drawing internal processes on the context diagram is a notation error that costs marks at every level above 3–4.
+
+	At **9–10**, the rubric requires *"no errors, inconsistencies or omissions"* across all three diagrams. Inconsistent entities between context and DFD is an inconsistency — even if both diagrams are otherwise correct.
+
+	---
+
+	## See also
+
+	- [Roadmap View vs Gantt Chart](/sd/C01/Roadmap%20View%20vs%20Gantt%20Chart) — same "common mistake" structure for a C01 diagram
+	- C02 Resources: [external reading and videos](/sd/Resources/C02-Resources)
+
+	---
+
+	← Back to [VCE Software Development Hub](/sd/VCE%20Software%20Development%20Hub)
/dev/null .. sd/C02/Explaining vs Describing Your Data Collection.md
@@ 0,0 1,70 @@
+	> **DRAFT** — under teacher review.
+
+	# Explaining vs Describing Your Data Collection
+
+	Hamilton College · Year 12 · 2026
+
+	The jump from 7–8 to 9–10 on Indicator 1 (Data Collection) comes down to a single word in the rubric: **"explains"** instead of **"describes"**. Every year, students hit 7–8 and can't understand why — it is almost always this.
+
+	---
+
+	## The rubric in plain language
+
+	| Band | What the rubric actually says | What that means in practice |
+	|---|---|---|
+	| **7–8** | *Describes how the data collected will be used to determine user characteristics and the technical environment* | You say **what** the data is for. "I used interviews to find out what features users want." |
+	| **9–10** | *Explains the use of the selected data collection methods* | You say **why** this method was the right choice for this kind of data. "I chose interviews over surveys because I needed qualitative insight into workflows that users couldn't easily articulate in a questionnaire." |
+
+	The word "explains" requires a **reason** — not just a statement.
+
+	---
+
+	## Side-by-side: same plan, two different bands
+
+	The scenario: a student whose project is a school assignment tracker. They used interviews and a survey.
+
+	### 7–8 version (describing)
+
+	> I used an interview with my client to find out what features they wanted in the assignment tracker. I also used a survey to ask students which subjects gave them the most homework. These helped me determine the requirements for the system.
+
+	**What's missing:** There is no reason given for *why* an interview was chosen over, say, a survey. There is no reason given for *why* a survey was used for students rather than interviewing them. The student is describing what happened, not explaining the decision.
+
+	### 9–10 version (explaining)
+
+	> I chose an interview for my initial data collection because my client — a teacher — needed to articulate complex workflow preferences that a survey's fixed-choice responses couldn't capture. A face-to-face conversation allowed me to follow up on unexpected answers in real time. I then chose a survey for the broader student group because I needed **countable data** — specifically, which subjects generated the highest homework load — and a survey's closed-ended questions give me numbers I can rank. Interviewing 30 students would have been impractical in the available time, and quantitative data served the purpose better here.
+
+	**What's there:** Each method has a **reason** tied to the *type of data needed* and the *practical constraints*. The student is not just listing methods — they are justifying each one against the alternatives they did not choose.
+
+	---
+
+	## The formula for an "explaining" sentence
+
+	> I chose **[method]** over **[alternative method]** because I needed **[type of data / depth / scale]**, and **[method]** allows me to **[specific advantage]**.
+
+	Write one of these for each of your three or more data collection methods. If you can't complete the sentence, you do not yet know why you chose that method — and the examiner will ask.
+
+	---
+
+	## Common traps
+
+	- **"I used interviews because they are good for qualitative data."** — This is still describing (a general property of interviews), not explaining your specific choice. Add: *why did this project need qualitative data at this stage?*
+	- **"I chose three methods to get a variety of data."** — "Variety" is not a reason. Name what each method adds that the others cannot.
+	- **"I used surveys because they are easy to send out."** — Convenience is not a justification the rubric rewards. Reframe it: *a survey allowed me to reach all 80 students in the year level simultaneously, which an interview schedule could not achieve within the one-week collection window.*
+
+	---
+
+	## Why VCAA cares
+
+	The C2-1 validation is a **presentation** — the examiner will ask follow-up questions. A student who has only described their methods will struggle to answer "Why didn't you just use a survey for everything?" A student who has explained their choices has already answered that question in their own plan.
+
+	Practise saying your explanations out loud before the validation. If you stumble, rewrite. The rubric rewards understanding, not recall.
+
+	---
+
+	## See also
+
+	- C02 Resources: [external reading and videos](/sd/Resources/C02-Resources)
+
+	---
+
+	← Back to [VCE Software Development Hub](/sd/VCE%20Software%20Development%20Hub)
/dev/null .. sd/C02/What Is an Entity.md
@@ 0,0 1,83 @@
+	> **DRAFT** — under teacher review.
+
+	# What Is an Entity? (It's Not Just a Person)
+
+	Hamilton College · Year 12 · 2026
+
+	On context diagrams and data flow diagrams, students frequently draw only the humans they can think of — "Student", "Teacher" — and miss every external system their software talks to. Missing an entity is a rubric error at every level above 3–4, because the rubric rewards *"relationships between the existing system, entities and data flows"*.
+
+	---
+
+	## The VCAA definition
+
+	> **Entity** — the users or external systems that interact with the system being created.
+
+	Two words matter: **users** (human roles) and **external systems** (non-human). Both go on your context diagram as rectangles.
+
+	---
+
+	## Types of entity — with examples
+
+	| Type | What it is | VCE SAT examples |
+	|---|---|---|
+	| **Human user (primary)** | The person the software is primarily built for | Student, Teacher, Administrator |
+	| **Human user (secondary)** | A person affected by the system's outputs | Parent, School Principal |
+	| **External software system** | An API, platform, or service your system sends data to or receives data from | Google Calendar API, Payment Gateway, Email Server |
+	| **External data source** | A data feed or file system outside your application boundary | School database, CSV import, Government open data |
+
+	---
+
+	## A quick test: is it an entity?
+
+	Ask three questions:
+	1. Does it send data **into** my system, or receive data **out** of it?
+	2. Is it **outside** the boundary of the software I am building?
+	3. Is it a **distinct role or system** (not an internal component of my software)?
+
+	If all three answers are "yes" — it is an entity. Add it to your diagram.
+
+	If it is *inside* your system (e.g. a function you are writing, a class in your code, a database table your code owns) — it is **not** an entity. It belongs on the DFD as a process or data store.
+
+	---
+
+	## Common omissions from student context diagrams
+
+	These are the entities students most often miss, sorted by project type:
+
+	| Project type | Commonly missed entity | Why it is missed |
+	|---|---|---|
+	| Any project with login | Authentication provider (e.g. Google OAuth) | Students think login is "inside" their app |
+	| Any project that emails users | Email server / SMTP service | Students don't model outgoing system calls |
+	| School management tool | Admin user or IT department | Students only think about the primary user |
+	| App using external data | External database or API (e.g. weather API) | Students model the API as a feature, not an entity |
+	| App with notifications | Push notification service | Treated as internal, but it is external |
+
+	---
+
+	## User stories → entities: the reliable method
+
+	Your `data-collection-plan.md` user stories are the best source of entities. For each story:
+
+	- **"As a [role]"** → that role is probably an entity (if they interact with your system directly).
+	- **"I want [goal] so that [benefit]"** → what external systems does achieving this goal require? Each one is a candidate entity.
+
+	Work through every user story before finalising your context diagram.
+
+	---
+
+	## Why VCAA cares
+
+	The C2-2 rubric at **5–6** requires *"illustrates the relationships between the existing system, entities and data flows"*. "Some errors or omissions exist" is still acceptable at 5–6. But at **9–10**, "no errors, inconsistencies or omissions exist" — a missing entity is an omission, and omissions cost you the top band.
+
+	The most common C2-2 omission flagged in past years: the email server or notification service that every project needs but few students draw.
+
+	---
+
+	## See also
+
+	- [Context Diagram vs Data Flow Diagram](/sd/C02/Context%20Diagram%20vs%20Data%20Flow%20Diagram)
+	- C02 Resources: [external reading and videos](/sd/Resources/C02-Resources)
+
+	---
+
+	← Back to [VCE Software Development Hub](/sd/VCE%20Software%20Development%20Hub)
sd/Resources/C02-Resources.md ..
@@ 4,6 4,16 @@
	---
+	## C2-0: General Foundations
+
+	### External Resources
+
+	| Resource | Source | Format | VCAA Mapping | Why It's Useful |
+	|----------|--------|--------|--------------|-----------------|
+	| [AI Disclosure Log — worked C02 example](https://git.jeremychen.au) | Hamilton College (AU) | Markdown template | AI disclosure — C02 authenticity requirement | Your `C020-AI-Disclosure-Log.md` task file contains a complete worked example entry for a context-diagram AI interaction. Use the four-field format (what you asked / what it produced / what you kept / what you changed) for every C02 AI interaction. Start logging in Week 1 — retrospective logs collapse under presentation questioning. |
+
+	---
+
	## C2-1: Data Collection
	### Existing Materials (CriterionXX/)
@@ 14,7 24,8 @@
	| Resource | Source | Format | VCAA Mapping | Why It's Useful |
	|----------|--------|--------|--------------|-----------------|
-	| [VCAA Assessment — Applied Computing](https://www.vcaa.vic.edu.au/curriculum/vce-curriculum/vce-study-designs/applied-computing/assessment) | VCAA | Reading | Data collection — official requirements | The authority on what VCAA expects from data collection evidence. |
+	| [VCAA Assessment — Applied Computing](https://www.vcaa.vic.edu.au/curriculum/vce-curriculum/vce-study-designs/applied-computing/assessment) | VCAA (AU) | Reading | Data collection — official requirements | The authority on what VCAA expects from data collection evidence. |
+	| [Qualitative Data vs Quantitative Data — Five Guys Example](https://www.youtube.com/watch?v=jC7rfXRpNp0) | YouTube (US) | Video | C2-1: labelling data as qualitative or quantitative | Uses a fast-food ordering scenario to show the exact distinction; concrete enough to apply directly to your own interview notes and survey results. Useful before completing `prepared-data.md`. |
	### Gaps — C2-1
@@ 33,7 44,9 @@
	| Resource | Source | Format | VCAA Mapping | Why It's Useful |
	|----------|--------|--------|--------------|-----------------|
-	| [Ryan's Tutorials — Data Flow Diagrams](https://ryanstutorials.net/software-design-and-development/data-flow-diagrams.php) | Ryan's Tutorials | Reading + visual diagrams | Context diagrams, data flow diagrams, processes, entities, data stores, data flows | Excellent free tutorial. Uses accessible language suitable for high school students. Covers DFD components, multi-level design, balancing, and 14 rules for valid DFD construction. Includes the 8-step creation methodology. |
+	| [Ryan's Tutorials — Data Flow Diagrams](https://ryanstutorials.net/software-design-and-development/data-flow-diagrams.php) | Ryan's Tutorials (AU) | Reading + visual diagrams | Context diagrams, data flow diagrams, processes, entities, data stores, data flows | Excellent free tutorial. Uses accessible language suitable for high school students. Covers DFD components, multi-level design, balancing, and 14 rules for valid DFD construction. Includes the 8-step creation methodology. |
+	| [NSW Software Engineering: Context and Dataflow Diagrams](https://www.youtube.com/watch?v=XeJs9sYAuMg) | YouTube (AU) | Video | C2-2: context diagram features; Level-1 DFD features; what goes on each diagram | AU secondary curriculum video that draws both diagrams side by side for the same system — directly addresses the common mistake of adding processes to the context diagram. Closest external resource to VCE notation. |
+	| [Extend and Include in the UML Use Case Diagram](https://www.youtube.com/watch?v=t7U0zz74xQg) | YouTube (UK) | Video | C2-2: «include» vs «extend» relationships; arrow direction | Focused explainer on the two most-confused UML relationships, including arrow direction. Watch before finalising your use case diagram and before the hand-drawn assessment. |
	| [Lucidchart — UML Use Case Diagram Tutorial](https://www.lucidchart.com/pages/uml-use-case-diagram) | Lucidchart | Reading + interactive tool | Use case diagrams: actors, use cases, associations, system boundary, include, extend | Well-structured tutorial with visual examples. Lucidchart can also be used as a free tool for students to draw their diagrams. |
	| [Lucidchart — How to Make a Data Flow Diagram](https://www.lucidchart.com/pages/data-flow-diagram/how-to-make-a-dfd) | Lucidchart | Reading + interactive tool | Context diagrams, data flow diagrams — creation process | Step-by-step guide to creating DFDs, starting from context diagrams. Students can use Lucidchart's free tier to create their actual SAT diagrams. |
	| [Lucidchart — Data Flow Diagram Examples](https://www.lucidchart.com/blog/data-flow-diagram-tutorial) | Lucidchart | Reading + visual examples | DFD components, symbols, levels | Examples of DFDs at different levels with explanations of each symbol type. Good reference for students while creating their own. |
@@ 41,16 54,23 @@
	| [Creately — Use Case Diagram Tutorial](https://creately.com/guides/use-case-diagram-tutorial/) | Creately | Reading + interactive tool | Use case diagrams — creation and relationships | Tutorial with an embedded diagram editor. Students can practice creating use case diagrams directly. |
	| [Visual Paradigm — Use Case Diagram Tutorial](https://online.visual-paradigm.com/diagrams/tutorials/use-case-diagram-tutorial/) | Visual Paradigm | Reading + visual | Use case diagrams — comprehensive guide | Detailed beginner's guide covering all UML use case diagram elements. |
+	### Wiki pages for C2-2
+
+	| Page | What it covers |
+	|---|---|
+	| [Context Diagram vs Data Flow Diagram](/sd/C02/Context%20Diagram%20vs%20Data%20Flow%20Diagram) | Side-by-side table of what can appear on each diagram; the most common notation mistakes (DRAFT) |
+	| [What Is an Entity?](/sd/C02/What%20Is%20an%20Entity) | Human and non-human entities; how to find all entities from user stories; common omissions (DRAFT) |
+
	### Gaps — C2-2
-	- **No VCE-specific video** walking through the creation of all three diagrams (context, DFD, use case) for a single software project. Generic UML tutorials exist but don't use VCE terminology or expectations.
-	- **Hand-drawing practice** — the SAT requires hand-drawn diagrams for validation, but all external resources focus on tool-based creation. Consider creating a resource on hand-drawing techniques for diagrams.
-	- **Include and Extend relationships** in use case diagrams — students consistently struggle with these. The Lucidchart tutorial covers them but a focused VCE example would help.
+	- **No VCE-specific video** walking through all three diagrams for a single project. The NSW video above is the closest AU-curriculum substitute. A teacher-recorded walkthrough would close this gap fully.
+	- **Hand-drawing practice** — no external resource covers the specific 45-minute timed rehearsal format used in the C2-2 validation. This is a candidate for a teacher-recorded video.
+	- **Excalidraw starter template** — a pre-built `.excalidraw` canvas with all three diagram skeletons would save students 10–15 min of setup time. Not yet built.
	---
	## Recommended Actions
-	1. **Ryan's Tutorials DFD page** is the standout external resource for C2-2. Assign as required reading for data flow diagrams.
+	1. **NSW Software Engineering video** (YouTube) covers context diagrams and DFDs side by side — closest AU-curriculum substitute for a VCE-specific explainer. Use alongside the [Context Diagram vs Data Flow Diagram](/sd/C02/Context%20Diagram%20vs%20Data%20Flow%20Diagram) wiki page.
	2. **Lucidchart** (free tier) is recommended as the tool for creating digital diagrams — it has templates for all three diagram types.
-	3. Consider creating a **video walkthrough** of drawing all three diagrams for a sample project, showing common mistakes students make.
+	3. **Teacher video needed** — a 6-min hand-drawing demo under timed conditions (all three diagrams) is flagged in `C022-Practice-Hand-Drawing.md` as the key gap between digital practice and test performance. No suitable external substitute found.
sd/VCE Software Development Hub.md ..
@@ 9,6 9,7 @@
	## SAT (School-Assessed Task) — Checkpoints
	- [C01 — Design Brief & Project Management](/sd/C01/C01-home)
+	- [C02 — Data Collection & Analytical Diagrams](/sd/C02/C02-home)
	## Resources