IELTS process diagram (Task 1): how to write it, with a model answer

A process diagram, sometimes called a process chart, shows how something is made or how something happens in nature: labelled stages joined by arrows. In Academic Writing Task 1 you describe those stages in order, in at least 150 words and about 20 minutes. The official format page lists "describe stages of a process or procedure" among the skills this task tests.

The main focus is the sequence of stages. Your overview names the main stages and where the process starts and ends; the body walks through them in order. If the diagram shows quantities, temperatures or durations, include them.

In GoPrep data, 32% of first process diagram answers were under 150 words, and 19% had none of the usual summary words such as overall or in general (537 students, 28 July to 26 September 2026). When students tried again, 54 of the 75 who had fallen short reached 150 words, and 18 of 29 added summary words.

Answers under 150 words showed up in all seven Task 1 types, not only in process:

What sets process apart is the grammar, as the table of suggested fixes further down shows.

What the examiner checks

Four criteria of equal weight:

• Task Achievement: key stages, a clear overview, accurate details.
• Coherence and Cohesion: a sequence the reader can follow.
• Lexical Resource: range and accuracy of vocabulary.
• Grammatical Range and Accuracy: varied and correct sentence structures.

The passive is especially useful in a man-made process, and time clauses (once it has dried) and relative clauses (which are then mixed) add range too.

The official band descriptors ask for "a clear overview" at band 7. Band 5 describes "a tendency to focus on details (without referring to the bigger picture)": a report that walks through the arrows with no overview.

In a man-made process (making bricks, recycling paper) it rarely matters who does each step, so the passive keeps the focus on the action: the cans are sealed. In a natural process (the water cycle) the subject often acts by itself, so the active sounds right: moisture evaporates. Still, choose the voice by the verb and its subject: when something is acted on, the passive fits nature too (the soil is enriched by fallen leaves).

The main tense is the present simple. After once or after, the present perfect stresses that a stage is complete (once the metal has melted), but the present simple works too.

Weak: trend language where there is no trend

Overall, the amount of paper increases throughout the process.

This diagram shows no quantities, so the sentence describes something that isn't there.

Strong: stages, start and end, plus the two phases

Overall, the process is linear and consists of seven main stages, beginning with the collection of used paper and ending with the cutting and packaging of new paper. The first four stages turn old paper into a clean pulp, while the last three turn this pulp into finished paper.

For a cycle, name the loop: Overall, the diagram shows a natural cycle of four main stages which repeats continuously.

What the AI examiner flags in process answers

In its feedback, the GoPrep AI examiner gives a Band Contract: a short list of priority fixes. Here is how often each kind of fix came up, compared with all Task 1 types together.

The passive stands out for process: the AI examiner suggested a passive fix in 33% of process answers, against 10% across all Task 1 types together. Maps are also high, at 29%, since they too describe changes people make. Two typical slips (our own examples): The shredded paper are mixed → is mixed; The paper shredded into pieces → is shredded.

Sequence words are rarely missing: only 6% of the 537 first answers had none. What matters is how you use them:

• Link by trigger. Once the metal has melted, it is shaped ties one stage to the last; The metal melts. Then it is shaped reads like a list.
• Refer back. Swap the paper... the paper for it, this pulp, these sheets.
• Choose by meaning. Avoid then in every sentence; repeating a linker that fits is fine.

For articles: a/an introduces a single countable thing the reader doesn't know yet (a machine); the marks one that is clear from the diagram, even at first mention (the machine shown in the diagram). Paper and water as materials usually take no a/an, but in to form a pulp, pulp means the soft mass that results, so a is fine. Keep labels such as pulp or cullet when there is no exact synonym. More words: Task 1 vocabulary guide.

The diagram above shows how recycled paper is produced. Summarise the information by selecting and reporting the main features, and make comparisons where relevant.

Fix a weak body paragraph

Here is a weak first body paragraph for this task. We wrote it to show common kinds of fix; it is not a learner's answer.

Then the paper is collect. Then it shredded. Then it mixed with water. Then the pulp is pressed into sheets.

The same part of the process, fixed:

To begin with, used paper is collected and sorted by type. Once it has been sorted, it is shredded and mixed with water and chemicals to form a pulp. This pulp is then cleaned to remove any ink and glue.

One paragraph can't prove a band, but these are the edits the band 7 descriptors point to.

Model answer (156 words)

The diagram illustrates the stages by which used paper is recycled to produce new paper.

Overall, the process is linear and consists of seven main stages, beginning with the collection of used paper and ending with the cutting and packaging of new paper. The first four stages turn old paper into a clean pulp, while the last three turn this pulp into finished paper.

To begin with, used paper is collected and sorted according to its type. Once it has been sorted, the paper is shredded into small pieces, which are then mixed with water and a number of chemicals to form a pulp. This pulp is subsequently cleaned so that any remaining ink and glue are removed.

At the next stage, the clean pulp is pressed and rolled out into thin sheets. After that, these sheets are dried and wound onto large rolls. Finally, the rolls are cut to size and packaged as new paper.

Why it works: the overview gives the number of stages, the start, the end and the two phases, with no stage detail. The first body paragraph covers making the pulp and the second turns it into paper; the main actions are passive and in the present, the linkers vary, and this pulp and these sheets refer back instead of repeating the paper.

Use while for the two routes after the check. A possible answer:

Overall, used glass bottles pass through six main stages, from collection at bottle banks to the delivery of new bottles to shops, and faulty bottles are returned to an earlier stage.

Once the cullet has been melted with sand at 1,500°C, it is shaped into new bottles. Every bottle is then checked: faulty ones are returned to the crushing stage, while the rest are sent to shops.

What changes compared with a straight line:

• The loop goes into the overview: it is part of how the whole process is organised.
• The number is copied exactly: 1,500°C, not "a high temperature".
• Cullet stays as it is: it is the label on the diagram.