What is a decision table, and when would you use one?

Test designJunior

In shortA decision table lists every combination of conditions and the expected outcome for each, so you don't miss a rule. Use it when a feature has several conditions that together decide the result.

Model answer

A decision table is a test design technique for business rules where several conditions combine to decide the result. Each column is a rule: one combination of conditions and its expected action.

Example: free shipping rule: “Members get free shipping. Non-members get it on orders over 50 EUR.”

	R1	R2	R3	R4
Is member?	Yes	Yes	No	No
Order over 50 EUR?	Yes	No	Yes	No
Free shipping	Yes	Yes	Yes	No

With two yes/no conditions there are 2 x 2 = 4 rules, so 4 test cases. Three conditions give 8, and so on. Building the table often reveals gaps in requirements: “What about a member with a discount code that brings the total under 50?” is a question to ask the product owner before anything is built.

When I use it: discounts and pricing, loan or insurance eligibility, permissions by role, form logic that shows or hides fields.

If the table gets too big, I merge rules where a condition doesn’t matter (R1 and R2 above: members always get free shipping) or combine it with pairwise testing.

Learn more: Decision Tables

What they're looking for

A clear explanation with a small example, and knowing when the technique is useful (business rules with combinations).

Common mistakes

Describing it without an example.
Not knowing how many combinations there are (2 to the power of the number of yes/no conditions).
Forgetting that impossible or duplicate combinations can be removed.

What is a decision table, and when would you use one?

Model answer

What they're looking for

Common mistakes

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