Process diagrams appear regularly in IELTS Academic Writing Task 1 and require a different approach from graphs and charts. Unlike data-based tasks, process diagrams have no figures or trends to describe — instead, you describe a sequence of stages. Many test-takers find these easier to score well on once they understand the format.
Two Types of Process Diagrams
| Type | Examples |
|---|---|
| Natural processes | Water cycle, life cycle of an animal, formation of a geological feature |
| Man-made processes | How cement is made, how paper is recycled, how electricity is generated |
Both require the same approach: describe all stages in sequence, using appropriate vocabulary for each transition.
Key Vocabulary for Process Diagrams
Sequencing Language
| Stage | Vocabulary |
|---|---|
| Beginning | First / To begin with / The process begins when / Initially / At the first stage |
| Middle | Subsequently / Following this / The next step involves / After this / Once X has occurred / This then |
| Parallel stages | Simultaneously / At the same time / Meanwhile / While |
| End | Finally / Ultimately / The process concludes when / At the final stage |
Passive Voice (Essential for Process Diagrams)
Most man-made process descriptions use passive voice because the agent (who does the action) is less important than the action itself:
- "The sugar is extracted from the cane."
- "The material is then heated to 400 degrees."
- "The final product is packaged and distributed to retailers."
Verbs for Process Descriptions
| Action | Verbs |
|---|---|
| Processing | is treated, is processed, is refined, is filtered, is converted |
| Movement | is transported, is transferred, is pumped, is fed into |
| Change | is transformed into, is converted to, becomes |
| Creation | is produced, is generated, is manufactured |
| Removal | is extracted, is removed, is separated |
Structure for Process Diagram Tasks
| Section | Content |
|---|---|
| Introduction | Paraphrase the prompt (what process is shown) |
| Overview | How many stages? Natural or man-made? Linear or cyclical? |
| Body 1 | First half of the process (stages 1–3 or 1–4) |
| Body 2 | Second half (remaining stages) |
Key difference from graphs: There is no "data" to select or highlight — you must describe ALL stages. Nothing should be omitted.
Band 7+ Sample Response — Man-Made Process
Question: The diagram below shows how cement is manufactured and then used in the production of concrete.
(Description: Stage 1 — limestone and clay are crushed in a crusher. Stage 2 — the crushed material is mixed. Stage 3 — the mixture is heated in a rotating heater at 1450°C. Stage 4 — the resulting material (clinker) is ground to produce cement. Stage 5 — cement is combined with water, sand, and gravel in specific proportions to make concrete. Stage 6 — the concrete mixer rotates to produce the final product.)
Band 7+ Response:
The diagram illustrates the sequential production process for cement, which is then used as a component in the manufacture of concrete.
The cement production process consists of five main stages before the final material is ready for use. Initially, two raw materials — limestone and clay — are fed into a crusher, which reduces them to smaller particles. The crushed materials are then combined in a mixer, after which the blended mixture is passed through a large rotating heater operating at approximately 1,450 degrees Celsius. This intense heat transforms the material into clinker, which is subsequently ground into fine powder to produce the finished cement.
In the second phase of the process, the cement is combined with three other materials — water, sand, and gravel — in specific proportions: 10%, 25%, and 50% respectively, with cement accounting for the remaining 15%. These ingredients are fed into a rotating drum mixer, where the continuous rotation blends them thoroughly to produce concrete.
(175 words)
Why it scores Band 7+:
- All stages covered in sequence
- Passive voice used consistently and naturally
- Specific details from the diagram included (1,450°C; proportions)
- Logical paragraph break at the transition to the concrete phase
- No data invented — only what is shown in the diagram
Band 7+ Sample Response — Natural Process
Question: The diagram illustrates the life cycle of the frog.
Band 7+ Response:
The diagram shows the key developmental stages in the life cycle of the frog, which follows a circular pattern that begins and ends with eggs.
The process begins with the laying of frog eggs in a body of water, typically a pond or stream. Following fertilisation, the eggs hatch within a period of approximately two weeks to produce tadpoles, which are small, aquatic organisms that breathe through gills. Over the subsequent weeks, the tadpoles undergo a gradual transformation: their bodies elongate, hind legs begin to develop, followed by front legs, and their gills are progressively replaced by lungs, enabling them to survive on land.
By approximately twelve weeks, the tadpole has developed into a froglet — a miniature version of the adult frog that is still partially dependent on aquatic environments. This stage gradually matures into a fully developed adult frog capable of independent land and water movement. The cycle then repeats as adult frogs return to water bodies to reproduce and lay eggs.
(174 words)
Common Mistakes in Process Diagram Tasks
| Mistake | Fix |
|---|---|
| Omitting stages | Include every stage shown in the diagram |
| Not using passive voice for man-made processes | "The material is heated" not "They heat the material" |
| Using active sequencing without transitions | Add "Following this...", "Subsequently...", "Once X occurs..." |
| Writing a graph-style overview with data | Overview describes: type of process, number of stages, cyclical or linear |
Practise IELTS Writing with Gabble — AI-powered Task 1 feedback with instant band scores on overview quality, sequencing, and vocabulary range.