DRAFT — under teacher review.

IPO Charts — Process Means Steps, Not the Answer

The Hamilton and Alexandra College · Year 12 · 2026

An IPO chart has three columns — Input, Process, Output — and you write one chart per functional requirement. The chart connects directly to the rest of your design work: your inputs should already appear in your context diagram or DFD, and your Process column should express the same logic as your pseudocode.

The trap that caps students at the 5–6 band is writing the Process column as an outcome instead of as steps. This page shows you exactly what that looks like, and how to fix it.

The core rule

Tip

Process = the steps your algorithm performs. If your Process cell could also be your Output cell, it is wrong.

The three columns do different jobs:

Input — the data that enters the functional requirement (trace these from your context diagram / DFD).
Process — the numbered steps or operations performed on those inputs. Think of it as pseudocode in plain English.
Output — the result produced after the inputs are processed.

Wrong vs Right — the same requirement, two ways

The functional requirement below is: calculate a sales bonus.

	Input	Process	Output
WRONG	Sales amount, Bonus percentage	Calculate the bonus	Bonus amount
RIGHT	Sales amount, Bonus percentage	1. Check if sales amount > 10,000. 2. If true, bonus = sales amount × bonus percentage. 3. If false, bonus = 0.	Bonus amount

Notice what went wrong in the WRONG row:

"Calculate the bonus" is just a restatement of the Output.
It tells you nothing about how the calculation works.
A marker cannot award credit for logic that isn't shown.

The RIGHT row shows the decision and the two branches. That is what earns marks in the upper bands.

How the three columns connect to your other design work

flowchart LR
    CD["Context diagram / DFD<br/>(identifies data flows)"]
    IPO["IPO chart<br/>(Input · Process · Output)"]
    PS["Pseudocode<br/>(same logic, formal syntax)"]
    CD -->|"inputs come from here"| IPO
    IPO -->|"process mirrors this"| PS

Your Process column and your pseudocode should describe the same algorithm. If they contradict each other, one of them is wrong — check both.

🎬 Watch

Note

Video coming soon.

🎯 Watch for: how a complete Process column maps directly onto a pseudocode IF–THEN–ELSE structure, making it obvious that the Process column is algorithm steps, not a label for the Output.

Common mistakes

Mistake 1: Process that copies the Output

~~"Work out the bonus amount."~~

This is just the Output column repeated. Replace it with the numbered decision steps.

Mistake 2: Missing the decision branches

~~"1. Calculate bonus using sales × bonus percentage."~~

This ignores the condition. If there is a threshold or an IF in the logic, both branches must appear in the Process column.

Mistake 3: Inputs not traced to diagrams

Your inputs should be data flows you have already documented in a context diagram or DFD. If an input appears in your IPO chart but nowhere in your diagrams, that is a consistency problem the marker will notice.

Mistake 4: One IPO chart for everything

Write one chart per functional requirement. Each requirement has its own inputs, its own logic and its own output — cramming multiple requirements into one chart makes the Process column vague by design.

Check Your Understanding

A student writes Process = "display the total price". What is wrong with this, and how should they fix it?

...

Answer: "Display the total price" is an outcome — it names the output, not the steps. The student should replace it with numbered operations: e.g. 1. Retrieve unit price and quantity. 2. Multiply unit price × quantity to get subtotal. 3. Add GST (subtotal × 0.10). 4. Display the result. The Process column must show the how, not the what.

Where should the inputs listed in your IPO chart already appear in your design documentation?

...

Answer: In your context diagram or data flow diagram. Inputs are data flows entering the system or a process — they should already be named and labelled in those diagrams. If an input appears in the IPO chart but not in any diagram, there is a consistency error to fix.

You have a functional requirement with a condition: "if the score is 50 or above, the student passes; otherwise they fail." How many branches should appear in your Process column?

...

Answer: Two branches. 1. Check if score ≥ 50. 2. If true, result = "Pass". 3. If false, result = "Fail". Both outcomes of the condition must be shown — leaving out the false branch means the algorithm is incomplete.