Bug Severity and Priority in Testing: Differences, Types, and Tips

If two different types of bugs made their way into your comfy abode, which would you decide to get rid of first? After taking a deep breath, you might choose to weigh your options. Perhaps one is poisonous, while the other is speedy and hard to track down. Bug priority and severity can be likened to real-life bug predicaments – the more pesky and damaging the bug, the more urgent the situation. 

While bugs might sound very software-esque, they have their own importance in the product management sphere that you’ll want to know about. So, what do you get out of this article?

• Distinguish between severity and priority.
• Learn how to play detective and determine bug severity.
• How to handle bug warfare and manage the different types of bugs.

What Is Bug Severity?

Bug severity refers to how much impact a bug could have on how something functions and the user experience. Is it just a minor inconvenience or could it completely make the software unusable? 

Severity exists on a spectrum, but it also takes a bunch of different factors into consideration. For example, what sort of features are affected by this bug? Is it just an aesthetic issue, or are users unable to access important functions? Aesthetics issues aren’t often severe, while anything that affects core functions is a lot more serious.

Types of Severity

Severity usually exists over a few tiers and can be customized depending on the business or whatever is being tested:

• Critical – A serious issue that prevents the entire platform from being used.
• Major – A big issue that collapses the entire core functioning of a system, with certain areas of a system still up and running.
• Medium – An issue that does cause problems with the system but where the system is still functioning okay.
• Minor – More of an annoyance than an issue but one that has to be addressed eventually.

What Is Bug Priority?

Bug priority is where the bug is placed on the to-do list. It determines the order which they’ll be addressed based on their individual impact. If they’re placed high on the list, it means they’re much more urgent and important to fix than other bugs. Like bug severity, there are many factors that affect priority. 

Types of Priority

Priority exists on less of a spectrum than severity does. Bugs are usually labeled low, medium, or high on the to-do list.

• High – The bug should be fixed as soon as possible as its severity is high.
• Medium – The bug really needs to be fixed, but there won’t be serious consequences if not addressed right away.
• Low – These repairs usually take a back seat until the high and medium tasks are taken care of first.

Bug Severity vs Priority

This graphic illustrates a general idea of how bug severity and priority interact – urgency increases as priority increases and as severity increases. While it’s totally possible for a critical severity bug to be low on the priority list (maybe that aspect of your software isn’t released yet, but when it does, it’ll be a huge problem), bugs typically become a high or medium priority when the issue is major or critical.

URGENCY ↓		Severity
Minor	Medium	Major
Priority	Low
Medium
High
	URGENCY ->

It’s all about striking the right balance based on the context behind the bug. The severity classifies the extent of the issue caused, but priority determines how much of the resources and effort should go to address them and how fast.

How to Determine Bug Severity?

There are typically three factors that influence the level of severity: usability, frequency, and security. Bugs that render software unusable, pose security issues and happen often are highly severe, whereas those that are on the other end of the spectrum aren’t nearly as severe. 

If we take a look at this bug severity and priority table created in Fibery, you’ll see that login issues are considered “Critical” on the severity scale. This means users are unable to log in. Even if it’s just a one-time occurrence, the fact that this has extreme effects on user impact means it needs to be fixed immediately. 

On the other hand, we have Performance Degradation as “Minor” on the scale. Slow loading times could be annoying to users or customers, but it doesn’t mean they won’t be able to use the software or place an order – it just means it’ll take an extra few seconds to perform actions. While it’s not worth abandoning everything else going on to fix, it’s still important to include it on the list.

How to Manage Different Types of Bugs

Staying organized and having a strategy will have you zapping bugs left, right, and center. Here’s how you can handle different combinations of severity and priority.

High Severity and Low Priority Example

A bug that causes a software or app to crash when clicking a specific button or navigating to a certain page lands itself high on the severity scale because it impacts the user experience. But why would it be a low priority, you ask? Well, perhaps it doesn’t happen all the time, and maybe the button or page isn’t overly important – it could be a nice-to-have FAQ page that could be fixed in a future update.

High Severity and High Priority Example

But let’s say we’ve got a serious security issue on our hands that could leak sensitive data to cybercriminals. Not only is it threatening the business and its users, but it needs to be fixed before that problem actually occurs. Therefore, this bug is a high-severity, high-priority case that needs to be immediately addressed with a patch.

Low Severity and High Priority Example

If you’ve discovered through user feedback or testing that a drop-down menu isn’t functioning and is minorly affecting a navigation process on your site, the bug could be classed as low severity. This is if that drop-down menu doesn’t have anything to do with core functions. At the same time, though, it’s still a high priority because it has a big impact on customer churn. You won’t want to turn off any new or existing customers, so you’ll want to shield against this by tackling the bug immediately.

Low Severity and Low Priority Example

Typos, a low-quality emoji, or a slightly off-centered image won’t kill your offering, nor are they severe or a high priority. If you’ve spotted a minor typo (colour instead of color for American English consistency, for instance), you can put this sort of issue on the back burner. It doesn’t affect the user experience, and it doesn’t pose any threats, meaning higher-priority tasks should take precedence.

Addressing Those Bugs

In product management, bugs aren’t about fixing code or reviewing system logs. It’s about keeping the user experience top-notch by prioritizing your efforts and resources.

With a 14-day trial of Fibery, you can generate all sorts of visuals, identify important insights, craft roadmaps, and do just about anything product development-related with everyone aligned.

Want to lead with more confidence? We’ve got more insights on our blog that could put you ahead of the pack.