The Hallway Test Method to Identifying Use Cases In Your Solution

Recently, I was sifting through tens of interview transcripts and hundreds of post-it notes to identify the main tasks in a people-management solution we are designing. My colleagues and I wrote down all the things the software needs to do and soon realized that the level of granularity and the names we were giving to tasks were not at a uniform level of granularity.

My friend and colleague Enric Gili-Fort, mentioned the hallway test method to me. When you want to identify the main tasks a user will perform using your product, (which will become a high level use case for your design team), ask yourself if this is something a person will be wondering while they are walking down the corridor.

For example, the person might be thinking "Oh! I need to let David know what my development goals for this year are" or "I need to send my travel request for that Conference next month" or "I need to order that book for my team".

The person is not going to think that "Oh! I need to open my browser and click on that submit button". 

I used this method with great success in the project. It helped me identify the main tasks from months of research work and defend my list of use cases with clear arguments.

Indy Young covers this in great details in her book Mental Models. The topic of identifying tasks is covered in details in Chapter 8. There is a section on the "Hallway Test Method" of identifying tasks.