Modes of Communication

This page contains excerpts from seminal work by Alastair Cockburn in the early days of the agile software development movement.  Before we dive into this, it's clear that communication technologies have improved dramatically since this work was published between 1999 and 2002.  However, the principle still stands, maybe just with a lower delta in effectiveness across the different modes, but it's a principle to remain mindful of when striving for high performance.


[1] The figure shows communication effectiveness dropping as modalities and timing are removed.  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.

What happens when we remove those characteristics, one by one?

Put people at opposite ends of a video link. In principle, the link has the same characteristics as physical presence. However, when we try it, the effect is not the same. Teammates working in Oslo and Lillehammer found that they only made design progress when they took the train trip to sit together. Even walking from the train station together was a more effective design environment than talking over a video link.


(But keep vocal inflection and timing e.g., use a telephone)

Most people speak while drawing. While drawing the line that connects two boxes, the person will say what is important to note. This visual / auditory timing information anchors information content. Putting two people over the phone eliminates this timing, along with facial expressions, gestures, and pointing.


(But keep the ability to ask questions e.g. email)

Without vocal timing, we can’t pause for effect, check for interruptions, speed up or slow down to make a point. Without vocal inflection, we can’t raise our tone or volume to indicate the surprise, boredom, or obviousness of the transmitted idea.


(But possibly reinstate one of the above factors)

Without the questions, the presenter must guess what the receiver knows, doesn’t know, would like to ask, and what an appropriate answer to the guessed question might be – without any feedback. In this set of communication media, we can still allow visual cues (videotape), or voice (audiotape).


(and we get… paper documentation)

In the above model, paper documentation comes out as the least effective communication medium available. The writer must guess at the audience, with no feedback, and does not get to use timing or emphatic signals, vocal or gestural inflections.

[2] The horizontal axis indicates the "temperature" of the communication channel. Warmer indicates that more emotional and informational richness gets conveyed.  E-mail is cooler than audio or videotape and two people communicating face to face is the hottest channel.

What we see in the graph is communication effectiveness rising with the richness (temperature) of the communications channel. Two people at the whiteboard are using the richest form.


VFS Note:  The use of the term "temperature" is part of a broader metaphor Alastair uses which draws parallels between the movement of information through people with that of the dispersion of heat and gas - Convection and Conduction being equated to the inevitable communication gaps and the energy cost of information transfer.  It was as part of this metaphor that Alastair coined the term information radiators to describe useful visuals and dashboards.