Effective Communication of Requirements


Effective communication of requirements requires more than documentation and broadcasting. Effective communication requires interaction and collaboration. Alistair Cockburn addresses this in his analysis of project successes and modes of communication.

Alistair’s Article

Alistair analysed three dozen projects over the course of two decades. He was trying to find common approaches and processes that would correlate with or predicate software project success. What he found instead was that people and communication had more of an influence over the success of a project than process. This may be the source of the “people trump process” quote.

Hat tip to Jeremy Miller, The Shade Tree Developer, for the reference, as part of his excellent article describing the ideal software team.
In his article, he presents a diagram of different forms of communication and their effectiveness. We’ve redrawn Alistair’s diagram here.

effectiveness of communication

The most effective communication is person-to-person, face-to-face, as with two people at the whiteboard. As we remove the characteristics of two people at the whiteboard, we see a drop in communication effectiveness. The characteristics that get lost are:

  • Physical proximity. I am at a loss to explain why, but being physically close to the other person affects the communication. Whether it is three-dimensionality, timing, smell, or small visual cues, physical proximity matters.
  • Multiple modalities. People communicate through gestures as well as words, often making a point by gesturing, raising an eyebrow or pointing while speaking.
  • Vocal inflection and timing. By speeding up, slowing down, pausing, or changing tones, the speaker emphasizes the importance of a sentence, or perhaps its surprise value.
  • Real-time question-and-answer. Questions reveal the ambiguity in the speaker’s explanation, or the way in which the explanation misses the listener’s background. The timing of the questions sets up a pattern of communication between the parties.

Characterizing people as non-linear, first-order components in software development, Alistair Cockburn

Visualizing The Analysis

When you look at the characteristics Alistair identifies, and overlay them on the diagram, you see the following:

characteristics of effective communication
The forms of communication can be clustered into two groups, one clearly more effective than the other. Within each group, there are more distinctions.

  • Physical Presence vs. Artifacts. Collaborating in front of a whiteboard or on the phone is more effective than an email exchange. While eMail and instant messaging allow for near real-time interaction, they lack the cues that come from physical interaction. Our brains are wired for listening and looking as the means to communicate. You can absorb information and express ideas through artifacts, but it is less efficient. Artifacts that you create lack the instinctive elements of nuance in communication. Active listening skills are refinements of what we’re already wired to do – and they make physical communication more effecient than when you write something down.
  • Interaction vs. Broadcasting. Strikingly distinctive is the difference between interaction and broadcasting. It is the difference between a community and an audience. Intuitively, you know that “throw it over the wall” is bad. Alistair’s research validates this. Determining the correctness of requirements requires interaction. You can use use cases to verify requirement correctness – but doing it without interaction is less effective.


Product requirements management requires communication. Different teams use different processes, and all processes involve communication. Effective communication must be interactive, not broadcast. Physical communication is more effective than communication with artifacts.

Artifacts serve a purpose – providing context, continuity, and a record of what has gone before. They are important for those goals, but relying on them as a communication vehicle in the absence of interaction will reduce the effectiveness of your team.

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