Diagrammatic reasoning is the ability to follow a process shown as a diagram, work out the rule each step applies, and use those rules to predict a result. In a diagrammatic reasoning test, inputs such as shapes, letters or numbers pass through a flowchart of symbols called operators, and each operator changes them in a fixed way. Your job is to decode what each operator does, then find a missing output, input or operator.
It is a form of logical reasoning that employers use to see how well you can handle unfamiliar rules and systems. You can see the format for yourself in a free diagrammatic reasoning test, which explains every answer.
How a diagrammatic reasoning question works
A typical question has three parts:
- Inputs. The things that go into the diagram, often a shape, a string of letters or a set of numbers.
- Operators. Boxes or symbols on the path. Each one stands for a single fixed change, such as “reverse the order”, “turn 90 degrees clockwise” or “swap black and white”.
- Outputs. What comes out at the end of each path.
You are shown several completed paths first. By comparing what goes in and what comes out, you work out the rule for each operator. Then you are given a new path with something missing and use the rules to fill the gap.
A short example
Here are two completed paths, written out in text.
| Path | Input | Operators | Output |
|---|---|---|---|
| 1 | ABCD | ★ | DCBA |
| 2 | JKLM | ★ then ● | LKJM |
Path 1 tells you that ★ reverses the order. In path 2, ★ turns JKLM into MLKJ. To get from MLKJ to LKJM, the first letter has moved to the end, so that is what ● does.
Question: what comes out if WXYZ passes through ● then ★?
● moves the first letter to the end: XYZW. ★ reverses it: WZYX. The answer is WZYX. The order matters. Applying ★ first and then ● would give YXWZ, and that wrong answer is the kind of option you will see in the list.
Our diagrammatic reasoning examples work through more questions like this, including ones that ask for a missing input or a missing operator.
Diagrammatic reasoning vs abstract reasoning
The two are often confused because both use visual puzzles. The difference is in what you are asked to do.
| Abstract reasoning | Diagrammatic reasoning | |
|---|---|---|
| What you see | A sequence, grid or group of shapes | A flowchart of inputs, operators and outputs, though some tests also include sequences |
| What you do | Spot the pattern and extend it | Decode each operator and apply it step by step |
| Typical content | Shapes only | Shapes, and often letters or numbers |
| Main skill | Recognising a pattern | Deducing and applying a set of rules in order |
In practice, the names overlap. Some test providers call their shape sequence questions diagrammatic reasoning. If your invitation says diagrammatic, expect at least some flowchart and operator questions, and prepare for sequences too.
What diagrammatic reasoning tests measure
A diagrammatic reasoning test looks at how you:
- work out rules from evidence, by comparing inputs with outputs
- apply rules in the right order, without losing track part way through
- keep several rules in mind at once, which matters when a path has three or four operators
- ignore detail that does not matter, because some features are there to distract you
No subject knowledge is needed. Everything you need is on the screen.
Who uses diagrammatic reasoning tests
These tests have long been common for engineering, IT and technical roles, where people need to understand systems, code or processes. They now also appear in graduate schemes and analytical roles in many sectors, wherever an employer wants evidence that a candidate can pick up a new set of rules and use them accurately.
The skill shows up at work in tasks such as following a process map, tracing why a system produced an unexpected result, or working out what each step of a spreadsheet model does from its inputs and outputs.
The question types you are likely to meet
Most diagrammatic reasoning tests use some mix of:
- finding the output from a given input and set of operators
- finding the input that produced a given output
- finding the missing operator in a path
- completing a sequence of shapes
- sorting diagrams into sets by the rule they share
Each type has its own method, explained in diagrammatic reasoning question types explained.
How to get better at diagrammatic reasoning
The rules used in these tests come from a fairly short list: reversing, rotating, reflecting, inverting colour, adding or removing an element, and moving items along. The more of them you have seen, the faster you recognise them. A few habits help from the start:
- decode one operator at a time, starting with a path that has only one or two operators
- write each operator’s rule down in a few words as soon as you are sure of it
- apply operators strictly in the order the diagram shows
- work out the answer before you look at the options
Our guide on how to pass a diagrammatic reasoning test covers these habits in more detail, along with timing advice.
Try a diagrammatic reasoning test
The quickest way to understand diagrammatic reasoning is to answer a few questions and read the explanations. Start with a timed diagrammatic reasoning practice test and note which operators take you longest to decode.
