Severity measures the technical impact of a defect on the system (how badly it breaks functionality), while priority measures the business urgency of fixing it (how soon it should be addressed). They are independent axes, and confusing them is a classic QA interview trap.
Severity is about the defect's effect: a crash or data loss is high severity, a cosmetic misalignment is low severity. Priority is about business urgency: how soon the fix is needed relative to other work. The crucial insight is that the two don't always move together, and all four combinations occur. High severity + high priority: checkout crashes for everyone — fix now. High severity + low priority: an app crashes only on a decade-old browser two users have — bad crash, but not urgent to fix. Low severity + high priority: the company logo is misspelled or wrong on the homepage — trivially 'broken' technically, but embarrassing and urgent to fix before a big launch. Low severity + low priority: minor padding off on an admin page — fix whenever. Severity is usually assigned by QA (technical judgment); priority is usually owned by the PO/business (though QA advises). Being able to give a crisp example of high-severity/low-priority and low-severity/high-priority is exactly what interviewers look for to confirm you truly understand the distinction.
A typo in the company name on the landing page is low severity (nothing is functionally broken) but high priority (it's highly visible and embarrassing right before a product launch), so it's fixed immediately — a textbook low-severity/high-priority defect.
| Combination | Example | Action |
|---|---|---|
| High severity + High priority | Checkout crashes for all users | Fix immediately / block release |
| High severity + Low priority | Crash only on a 10-year-old browser 2 users have | Log; fix in a later sprint |
| Low severity + High priority | Misspelled brand name on the homepage pre-launch | Fix now despite minor technical impact |
| Low severity + Low priority | Minor padding off on an internal admin screen | Fix when convenient / backlog |
Scenario: In an interview you're asked: 'Give me a real example of a high-severity but low-priority bug, and a low-severity but high-priority bug, and explain who decides each.' How do you answer?
Memorize one crisp example of each mismatched case — the misspelled-logo (low sev/high pri) and crash-on-ancient-browser (high sev/low pri) — they're the fastest way to prove you get it.