Exception & Alternate Flow in Use Case

Instructor: Olga Bugajenko

Olga is a registered PRINCE2 Practitioner and has a master's degree in project management.

How can you know, which of the alternative routes will take you to your destination, and which will get you lost? Learn about the differences between alternate and exception flows in a use case.

What Is A Use Case

Quite often, there is more than one way to reach a particular goal when using the software. For example, both selecting 'Save' in the 'File' menu and pressing Ctrl+S buttons will save a Word document. On the other hand, there are also a lot of opportunities for you to not reach a desired goal of saving your document - for example, by clicking on the 'Don't Save' button when attempting to close the software. How can a software developer ensure that the software meets user expectations in each of those cases?

A use case is a method for capturing software requirements as a scenario of repeatable order of actions initiated by the user to reach a desired result. Usually, a preferred course of actions is documented as a basic flow. In addition to that, alternate flow and exception flow are included into the use case.

Alternate Vs. Exception Flow

The alternate flow is a series of actions in non-random, repeatable order, different from the basic flow, which still delivers the desired result to a customer. Imagine that you want to find a friend on a social network. The easiest way to do so is to navigate to the search bar and type in your friend's name and surname - this scenario was likely documented as the basic flow for looking up people when the social network was developed. However, if you cannot remember the surname of your friend, you might also browse your photo album until you find a photo, where both of you are tagged. Under this scenario, you will find your friend's profile by clicking on a photo tag.

Contrary to the basic and alternate flows, the exception flow are any actions that will cause the user to not achieve the desired result. The main benefit of the exception flow is its focus on potential problems a user might experience. This gives the software developer an opportunity to develop a feature that would mitigate the issue.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account