REQUIREMENTS & USE CASES
“At Apple we come at everything asking, “How easy is this going to be for the user? How great it is going to be for the user?”… Everybody says, “Oh, the user is the most important thing,” but nobody else really does it.”
– Steve Jobs
To make great products and services, create great requirements and use cases. There are so many decisions that go into the design of a product or service, and requirements are the necessary puzzle pieces to both optimize design features and trade-offs. The development of a new product or service requires significant resources, and great requirements serve as the rough clay, from which to carve the final product. You can also think about them as the recipe for the product and service. If you get the requirements and use cases right, the product or service will be a winner.
It is critical to the success of any organization that the products and services they design and deliver to customers, tightly align with and hopefully exceed the customers’ needs. Organizational functions should also design their services to exceed their customers’ needs.
What are Requirements?
One of the first steps in defining a new product, service, process, or system is to define the requirements, which are particular capabilities or design attributes. Functional requirements describe what a product or service does to fulfill a customer need. These include features and functions derived from use cases, which document how a user interacts with a product or service. Non-functional or operational requirements are behind-the-scenes operational and design attributes not obvious to a user. Non-functional requirements can include performance, usability, durability, security, and financial (price and cost) requirements. Functional requirements can be thought of as what a product needs to do for a customer, while non-functional requirements can be thought of as the constraints for which a product or service needs to be designed to meet or exceed. A list of the most prevalent categories of functional and non-functional requirements is below.
Properly defining requirements, based on the prioritized needs and wants of the target customers is essential in designing and developing a winning product or service.
What are use cases?
A user or customer interacts with a product or service to fulfill a need or want. Use cases define the interactions between a user and a product or service. Use cases help define the functional requirements, or what a product or service needs to do to fulfill the needs and wants of customers. A use case starts with an “actor,” or the “who,” which is a particular customer or user of a product or service. Actors can also be other products or services, stakeholders, administrators, organizations, or functions. You visually represent a use case visually represented as an oval, reinforced by a description of a particular interaction between the actor and the product or service.
Use cases can be linked by arrows to represent a flow. There is typically the main flow of interaction, and alternative flows. For instance, the main flow of interaction between a bank customer and an ATM would focus on the flow of interactions to withdraw money from the ATM, which is the most prevalent use case of an ATM. While alternative flows would include such use cases as entering the wrong pin, insufficient funds, depositing checks, transferring money, and checking balances.
Use cases typically define the “how”, often the “where”, and sometimes the “when”, of interactions between an actor and product or service. Take a look at the ATM example below.
Use cases are simple and effective in making typically hidden assumptions explicit. As an example, working at Goal Zero, we used use cases to brainstorm all of the places customers use portable charges to charge their phones or other electronics. And, as we brainstormed, we realized some of the most common places people will charge their phone using a portable battery charger is in the car, pant pocket, table, bag, and outside. Understanding these different use cases drove good decisions around design, environmental, and material requirements.
Use cases in sales & marketing
While use cases define functional requirements; I’ve also found them extremely helpful in creating effective sales & marketing. Let’s take a step back. Strong marketing is about identifying the most important needs and wants of the customer target and demonstrating how a product or service can fulfill those needs and wants. This translates into showcasing the most important use cases in sales material and advertising.
A good example includes a diaper commercial that focuses on the use case of changing a diaper in the middle of the night. The advertisement focuses on a very sleepy mom, stumbling into their screaming crying baby’s room to change their wet diaper. The diaper manufacturer then focuses on how their diaper keeps babies 3x drier than other leading diapers, so you don’t have to face the dreaded use case of changing a wet diaper in the middle of the night. It was a pretty interesting example of really tying the advertising message to one of the most important use cases. Check it out below.
As you find yourself watching TV, online, or looking through a magazine, I encourage you to view the ads through the lens of use cases. You’ll probably be able to pick out the good from the bad, on account of how well they nail the right use case to try and drive demand for their product or service.
How do you create great use cases and requirements?
Use cases and requirements are pretty simple to build once you start putting yourself in the users’ shoes. Some of the best practices include:
Use the voice of the customer tools
When creating use cases and requirements utilize the voice of the customer tools, such as surveys, observation, ethnography, customer reviews, and focus groups. Ethnography and observation are good to define use cases. While surveys and focus groups are useful to help prioritize which use cases and requirements users value more than others.
Use the 5 Ws and 1 H
In starting out in defining use cases and requirements the 5 Ws (Who, What, Why, Where, When) and 1 H (How) can serve as a helpful brainstorming framework. Simply start with “who” uses the product or service, and prioritize the different “whos” or segments. The “what” is the product or service. The “why” reflects customer needs and wants. While the “how” is the flow and interaction or use cases between the user and the product or service.
Requirements represent the constraints that the design is trying to optimize. Imagine being 90% done with a product or service design, only to realize there is a major regulatory or usability requirement the team didn’t think through, which necessitates a full redesign. Unfortunately, it happens more often than one would think. Take enough time to ensure all of the categories of requirements have been thought through. The list a few pages back can be helpful.
Define the right level of specificity
Use cases can be defined broadly or minutely. In the beginning, aim for the use case name or oval to be defined broadly, while the use case description goes into more of the minutia. Use cases are meant to be read more like a story of the interaction, rather than a staccato robotic readout.
Translate your use cases and requirements into test cases
If you’ve created great use cases and requirements, then you’ve done 80+% of the work to create the test cases that can be used to test the product or service.
Get some training
Creating use cases and requirements is like learning a language. In fact, use cases are typically based on the Unified Modeling Language (UML). There are many online workshops and courses that are helpful in learning the ins and outs of use cases and requirements.
DOWNLOAD THE USE CASE TEMPLATE
To get you going on use cases & requirements, download the free and editable Use Case Template.