When we test we think about the users of the functionality and we include their needs in our testing. Creating categories of customers, such as internal and external, can help us understand our customers’ uses of the functionality.
Dr Joseph Juran advocated viewing customers as either internal or external customers. Juran was born in Romania and emigrated to the USA. He, like W. Edwards Deming, worked with Walter Shewhart and helped the Japanese economy recover from World War Two. He also taught quality control at New York University and worked with Steve Jobs.
Dr Juran said that identifying customers is the first step in planning for quality[1]. He defined a customer as “someone who is impacted by the product”. He also said that customers may be external or internal.
An external customer is a customer who is external to the company or organisation. They may be a paying client, government regulatory bodies, international regulatory bodies or the public.
Departments and people within a company often supply products to one another, these are internal customers. They are not customers in the traditional sense as they are not paying clients, but they are often called customers.
Juran recommends creating a flow diagram to help identify customers. The flow diagram can show the steps involved in the process and help identify customers[1].
He says that customers can also be divided into classes. If there are many customers the Pareto principle can be used to classify customers into the vital few and the trivial many as this helps you to focus your efforts where it will have the most impact.
It is important to consider how the functionality we are testing impacts internal customers as the functionality we are developing will impact others within the company. Examples of this would be that the functionality could create additional work for the customer service team if functionality is complex.Sales and marketing are also impacted by the features a team is working on and it is useful to view sales and marketing as customers so that they are kept informed of new features.
Juran’s way of looking at external customers is useful too as maybe a playing client uses your product to provide a service to someone else such as “the public”, and your testing can then also take that other person’s needs into account. The success of the application that you are testing may depend on the quality of the service being provided by your paying client to hi/her paying clients.
I find that this categorisation of customers is useful because it provides a structure that enables me to think about external customers like clients but also about internal customers like customer service.
References:[1] Juran’s Quality Handbook Fourth Edition
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