IELTS process diagram Task 1: passive, tense, Band 9

Open a process diagram after weeks of practising line graphs and the first instinct is the wrong one: you look for the numbers. There are none. No axis, no percentages, no trend to sum up. A process diagram asks for something the other Task 1 figures never do, a description of how something is made or how it happens, in order, and the grammar that carries it is different too. Miss that and a fluent writer still lands at Band 6.

This is a guide to the process diagram specifically: why the passive and the present tense do most of the work, how natural processes differ from man-made ones, the sequencing language that holds it together, and a Band 9 model with the reasons it scores. It sits under the Writing Task 1 guide and the seven chart types; here we go deep on this one.

A process diagram has no numbers: what changes

Every other Task 1 figure gives you data to select and compare. A process diagram gives you stages to sequence. That single difference resets the rules.

There is nothing to measure, so the trend vocabulary from a line graph and the proportion language from a pie chart have no place here. Reaching for "increased" or "the largest share" describes something the diagram never showed, which reads as a misunderstanding of the task. What you report instead is the flow: what happens first, what each stage produces, and what comes out at the end. The skill being marked is whether a reader who never saw the diagram could rebuild the process from your words alone.

The passive and the present tense

This is the figure where tense and voice are almost fixed, and getting them right is half the grammar mark.

Present simple, because a process is timeless. A diagram of how cement is made is not describing one afternoon at a factory; it is describing what happens every time. So the tense is the present simple throughout: the clay is mixed, the mixture passes into a rotating kiln, not was mixed or will pass.

The passive, because the agent does not matter. In a man-made process, who does each step is irrelevant and usually unstated. What matters is the action. So the bottles are collected and sorted is better than workers collect and sort the bottles, and the whole report leans on the passive: is heated, are compressed, is transported, are packaged. This is the grammar criterion's main test on a process, and a report that stays in the active voice throughout reads as less controlled, however accurate.

There is one nuance most guides skip. A natural process, the water cycle or the life cycle of a frog, often has no human agent at all, so it tends to take the present simple active: water evaporates, the eggs hatch, the tadpoles develop legs. You use the active here because the thing itself acts. A man-made process, making paper or recycling glass, leans on the present simple passive, because a person or machine acts on the material. The rule of thumb is reliable, but read the diagram and follow what it actually shows: a natural process can still take a passive where something is acted upon, and a man-made one an active where the material itself moves.

The overview: shape, not steps

Write it or accept a Band 5. The Academic Task Achievement descriptor first mentions an overview at Band 6, "a relevant overview is attempted," and Band 5 describes the report without one, "there may be a tendency to focus on details" instead of the bigger picture.

On a process, the overview does not list the steps. It names the shape of the whole thing. Three facts do it: how many stages there are, where it starts and ends, and whether it is linear (raw material in, finished product out) or cyclical (it returns to the beginning). Something like: "Overall, the process consists of seven main stages, beginning with the digging of raw clay and ending with the delivery of the finished bricks, and it is a linear rather than a cyclical process." No individual step, and yet the reader knows the structure before a single stage is described. That is the Band 6 checkpoint cleared.

The linear-or-cyclical call matters, because it changes the closing. A linear process ends with a product. A cyclical one, like the water cycle, ends by returning to its start, and saying so ("the cycle then repeats") is what shows you read the diagram as a whole.

Sequencing language holds it together

The coherence and cohesion mark on a process is made almost entirely of sequencing language, because the stages have to arrive in order and the reader has to feel the order.

The trap is "firstly, secondly, thirdly, fourthly," repeated to the end. It works, and it caps the cohesion mark, because the Band 7 descriptor wants cohesive devices "used flexibly," not a counter. Vary them. To begin: initially, first, to start with. To continue: next, then, after this, following this, once the clay has been shaped, at the next stage. To finish: finally, in the last stage, at which point.

Two constructions lift the range further. The "once/after + present perfect" pattern links two stages in one sentence: once the bottles have been washed, they are crushed into small pieces. And the purpose clause names why a stage happens: the mixture is heated to remove any moisture. Both show the grammar range the higher bands look for, and both read as more fluent than a chain of "then... then... then."

Precise process verbs

Vocabulary on a process is mostly verbs, and swapping vague ones for precise ones is the Lexical Resource win here. "Put together" becomes assembled. "Made pure" becomes purified. "Heated to a high temperature" becomes fired for clay or brick, or smelted when metal is extracted from ore. Other workhorses: extracted, filtered, ground, moulded, dried, cooled, packaged, distributed. The caution from the descriptor applies as ever: a precise verb you control beats a rare one you are guessing at, so use fired for clay because you know it, not a word you met once in a list.

Task Achievement, band by band

At Band 7, the Academic response "presents a clear overview, the data are appropriately categorised, and main trends or differences are identified," which on a process means an overview naming the stages and shape, and the stages reported in a clear, complete order. At Band 6, only "a relevant overview is attempted," and stages may be missed or muddled. At Band 5, "there may be a tendency to focus on details" with no bigger picture, which is a report that starts describing stage one with no overview at all. The other repeated fault, leaving out a stage so the process no longer connects, is what the descriptor means by a task not fully covered.

A Band 9 model, and why it works

Take a common prompt: "The diagram below shows how bricks are manufactured for the building industry."

The diagram illustrates the process by which bricks are produced for use in construction.

Overall, brick manufacturing consists of seven distinct stages, beginning with the digging of clay from the ground and ending with the delivery of the finished bricks. It is a linear process, and human involvement is required at several points.

At the first stage, clay is dug out of the ground using a large digger. This clay is then passed through a metal grid onto a roller, which breaks it up, and sand and water are added so that the material can be shaped. The mixture is formed into bricks either by placing it in a mould or by using a wire cutter.

Once the bricks have been shaped, they are left to dry in an oven for between 24 and 48 hours. After drying, they are fired: first in a kiln at a moderate temperature of 200 to 980 degrees, and then in a second kiln at a much higher temperature of 870 to 1300 degrees. The bricks are subsequently cooled in a chamber for two to three days, after which they are packaged and delivered to their destination.

Read what the report does. The introduction paraphrases the prompt rather than copying it. The overview gives the number of stages, the start and end, and that it is linear, with no individual step described. The two body paragraphs run in strict order, split where the material changes from wet clay to fired brick. Every stage is passive and present tense (is dug, are added, is formed, are fired, are cooled, are packaged), the sequencing varies (at the first stage, then, once... have been shaped, after drying, subsequently), and the numbers that do appear are the ones printed on the diagram (temperatures, drying times), not invented data. Around 190 words, and a reader who never saw the diagram could draw it.

The mistakes that cap you

No overview is the Band 5 trap, already covered. Missing or reordering a stage breaks the process so it no longer connects, which the "appropriately addressed" line marks down. Slipping out of the passive, or drifting into the past tense ("the clay was mixed"), is the grammar fault that shows up most, because the habit from graph answers carries over. Hunting for numbers and trends where there are none, "the amount of clay increased," describes something the diagram never showed. And "firstly, secondly, thirdly" all the way down holds the cohesion mark at 6 by using one device on repeat.

Drill it in five minutes

• The voice-check drill. Take five process diagrams and label each natural or man-made, then write the tense and voice: present simple active for natural, present simple passive for man-made. Thirty seconds each, and the grammar is decided before you write.
• The overview drill. For one diagram, write only the overview sentence: number of stages, start and end, linear or cyclical. No individual step.
• The connector-swap drill. Take a process you wrote with "firstly, secondly, thirdly" and rewrite the joins using "once... has been," "after this," and a purpose clause. That swap is most of your coherence mark.

That's the idea behind IELTS Drills. Feedback comes back tagged to a single Band Descriptor, so when a Task 1 report lands at 6.5 you can see whether the half-band went on a missing overview, a dropped stage, or the tense and voice, and drill that one in five minutes a day.

Frequently asked questions

What tense is used for a process diagram? The present simple, because a process is timeless. Man-made processes take the present simple passive (the clay is fired); natural processes take the present simple active (water evaporates). Past and future tenses are wrong for a standard process.

Do I use the passive voice throughout? For a man-made process, mostly yes, because the action matters more than who performs it. A natural process with no human agent uses the active voice instead.

How do I write the overview for a process? Name the number of stages, where the process starts and ends, and whether it is linear or cyclical. Do not describe any single stage; the overview is the shape, not the steps.

Are there numbers or trends in a process diagram? No. Unlike graphs, tables and charts, a process has no data to compare, so trend and proportion language does not apply. Report the sequence of stages instead. Any numbers printed on the diagram (times, temperatures) can be used as given.

How do I avoid repeating "firstly, secondly"? Vary the connectors (initially, next, after this, once... has been completed, finally) and use "once/after + present perfect" to link stages. Repeating a counter caps the coherence mark.

How long should it be? At least 150 words, with roughly 170 to 190 giving you room to cover every stage. Aim for 20 minutes, because Task 2 is worth twice as much.

The bottom line

A process diagram is the Task 1 figure with no numbers, so the skill is sequence rather than selection. Decide first whether it is natural (present simple active) or man-made (present simple passive), write an overview that names the number of stages and whether it is linear or cyclical, then run the stages in strict order with varied sequencing and precise verbs. For the other figures and how each changes the overview, the chart-types guide has the map, alongside the line graph, bar chart, pie chart, map, table and combination deep dives. With IELTS Drills, the feedback tells you which axis is still costing you the 0.5, five minutes a day.