Clerk measuring customer for a suit of clothes, San Antonio, Texas.

A friend of one of the authors once designed and implemented the user interface for a large system. He got input from customers on how to make it useful for them. Unfortunately, the requirements writers had a different idea, and made him remove the features the customers liked. But then the customers asked for the missing features, and the requirements writers were forced to relent. I guess it didn't help relations between my friend and the requirements writers.

...an organization is in place, and its Quality Assurance function has been generally shaped and chartered. The Quality Assurance (QA) function needs input to drive its work. Many people in the enterprise are concerned about quality.

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It's important that the development organization ensures and maintains customer satisfaction by encouraging communication between customers and key development organization roles. This isn't the responsibility of any single "customer satisfaction" organ, but the need pervades the entire organization structure. Most organizations are averse to direct contact between developers and customers, fearing that the developers are "loose cannons on deck" who will promise to deliver things that go beyond the scope of a job.

Yet you can't know all the requirements up front, so developers need to keep going back to customers for more information--and customers need to keep coming back to developers with their insights, particularly when developers BuildPrototypes.

Requirements changes occur even after design reviews are complete and coding has started.

Many organizations depend on their marketing organization to provide requirements and needs. But marketing doesn't provide design data (BibRef-BeyerHoltzblatt1998], p. 30). The best that marketing can do (or should do) is to understand what will sell and why people will buy what you want to sell. Designers in turn must understand how people will use the product in a way that creates value for them. Good value sometimes leads to good market potential, but marketing usually looks at other factors (brand name recognition, product name and posturing n the market) about which designers care little.

Missing customer requirements are a serious problem: most problems in software systems can be traced to requirements problems ([BibRef-Daley1977]; [BibRef-Boehm1976]). Yet it seems like so much effort to elicit them — which is work that is not directly producing a marketable artifact. It seems like makework and overhead.

Customers are traditionally not part of the mainstream development, which makes it difficult to discover and incorporate their insights. Yet customer contact correlates with project success [BibRef-KeilCarmel1995].

Trust relationship between managers and coders are often strained, so you don't want them to be the sole intermediary between developers and customers.


Closely couple the Customer role to the Developer and Architect, not just to QA or marketing. In short, developers and architects must talk freely and often with customers. When possible, engage customers in their environment rather than brining them into your environment.

Two things are necessary for this to happen: opportunity and culture. Developers must have the opportunity (and the means) to communicate with customers. They should meet customers personally to establish trust and free flow of communication.
But these visits will be superficial if the organization culture builds walls between customers and developers. In particular, if system requirements must go through a lengthy formal process to be approved, the developer will be hamstrung -- unable to respond to customer requests. Therefore, the organization must develop a culture where developers have some latitude to respond to customers. This is not saying, however, that all control of requirements should be relegated to the developer. Order is necessary.

Beyer and Holtzblatt note that "many common ways of working with customers remove them from their work." ([BibRef-BeyerHoltzblatt1998], pp. 36-7). One way to help this is by "putting designers and engineers directly in the customer's work context" ([BibRef-BeyerHoltzblatt1998], p. 20). This is particularly important if you are using customer engagement to create wholly new market directions for the enterprise, rather than refining existing work. Putting developers in the customer work environment also trains developers' intuition about good design and good human interfaces, and this intuition can fill in when specific detailed requirements are unavailable [BibRef-BeyerHoltzblatt1998], p. 35).

Language is a key element of culture that can smooth customer engagement if treated properly, and smother it if treated badly. Don't make your customers learn UML or other technical notations; do your best to learn their language and to communicate with them in the terms of their culture.

QA can monitor the relationship to keep the direction within contractual business limits, while allowing a free flow of insights back and forth between developers and customers. Such communication can often flow unimpeded; however, see the pattern GateKeeper.

Note that this pattern is all about relationships and culture. It is the culture of respect for and communication with customers that makes the communication effective, for example, during the writing of use cases, as described in ParticipatingAudience ([BibRef-Bramble2002], p. 35).

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This pattern supports requirements discovery from the customer, as required by ScenariosDefineProblem and BuildPrototypes. Other patterns like FireWalls also build on this pattern. The pattern RecommitmentMeeting is a more formal derivative of this pattern in a different context.

A good understanding of customer needs can avoid rework after implementation is done. While it is also important to continuously engage customers through each development episode of iteration, early understanding helps launch the effort in the right direction. A Navision project in Copenhagen felt that improvements in customer engagement helped save time on their development schedule (from a draft pattern "Scandinavian System Development" by Flemming Pedersen, 24 January 2002).

This was a strong pattern in the Borland Quattro Pro for Windows case study. Also, see [BibRef-Floyd1992] and in particular the works of Reisin and Floyd therein.

Some processes and methods are founded on customer engagement, such as IBM's Joint Application Development. Other methods are conducive to customer engagement, such as Cunningham and Beck's CRC design technique. Other methods, and especially most CASE-based methods, are indifferent or harmful to customer engagement.

Even some of the best customer engagement techniques tend to stop once they achieve some level of contractual agreement about what is to be delivered. Customer engagement in agile processes goes far beyond that. Developers need to assimilate the context in which their product will be used: this is called contextual design. Contextual design means gathering data on customers' models of how they do their work rather than creating models of how the program will solve the problem. Use Cases are about the latter; contextual design is about the former. See [BibRef-BeyerHoltzblatt1998].

The pattern is "EngageCustomers", in the plural, to support a domain view and to avoid being blind-sided by a single customer.

The project must be careful to temper interactions between Customer and Developer, using FireWalls, GateKeeper, and the QA organizational presence as in EngageQualityAssurance. A big part of interacting with the customer is to learn how they want to interact with the project as the unfolding software uncovers problems in requirements and systems engineering (see ApplicationDesignIsBoundedByTestDesign).

Note that "maintaining product quality" is not the problem being solved here. Product quality is only one component of customer satisfaction. Studies have shown that customers leave one company for another when they feel they are being ignored (20% of the time), or because the attention they receive was rude or unhelpful (50% of the time). For customers having problems that cost over $100 to fix, and the company does not fix it, only 9% would buy again. 82% would do business with the company again if the problem was quickly resolved after they complained. (The source for the former pair is The Forum Corporation; for the latter pair, Traveler's Insurance Company [BibRef-ZuckermanAndHatala1992].)

Joe Maranzano [BibRef-Maranzano1992] notes that this pattern probably should come earlier in the language. However, it is important that the project roles be defined first--particularly those that interact with the customer, and those that are driven by customer input (such as Quality Assurance). Said in another way, the organization exists to serve the customer, so the organization should be in place before the customer is fully engaged.

This pattern works only if customers are directly accessible to the development team. If that is impossible for business reasons or because of geographic separation, consider SurrogateCustomer.