Principles of Design #58 – Signal-to-Noise Ratio

Jul 22 2014

Signal-to-noise ratio is the ratio of relevant to irrelevant information in a display, and one of the most important outcomes for a designer of any system, product or communication is to design the highest possible ratio of signal to noise. Communication is all about the creation, transmission and reception of information, and during each of these stages the signal is degraded and irrelevant information (noise) added. Such degradation reduces the amount of useful information with a lower amount of signal and a greater amount of noise (hence a lower signal-to-noise ratio). Good design always maximises signal and minimised noise.

In order to maximise signal, a designer should communicate information clearly and with minimal degradation. Unclear writing, inappropriate visuals, ambiguous icons and labels can all lead to inefficient communication, whereas simple and precise designs help audience or users to focus on the meaning, maximising cognitive fluency and minimising performance load. For example, using the right kind of graph to present a certain kind of data, making sure that doors with handles ‘afford’ opening by pulling, and that different senses provide the same ‘signal’ when using a product or service.

I argue in Brand esSense that this also applies to sensory design (or any design). Sensory information has multiplicative effects when different signals are congruent (read more here), meaning that signal-to-noise ratio can be significantly increased each time that an additional sensory touch point shares the same consistent ‘message’ (and can be significantly reduced when sensory touch points conflict).

Thinking in terms of signal-to-noise ratio leads to good design decisions. Emphasising key aspects of a design by highlighting increases the ratio, as does minimising noise by removing unnecessary elements. For example, in a graph, table or overall report, any unnecessary piece of data, graphic, line or symbol takes attention away from what is important in conveying meaning. As Albert Einstein once said, “Everything should be made as simple as possible, but not simpler.”

Designers and marketers should always maximise the signal-to-noise ratio by increasing signal with simple designs and carefully selected strategies, enhancing key messages with highlighting and minimising noise by removing unnecessary elements and minimising the expression of unimportant elements. Always use accepted conventions (such as category and cultural norms) and be consistent in implementation across different executions.

All communication and design is fundamentally about maximising the ratio of signal to noise.

Universal Principles of Design by Lidwell, Holden & Butler

Brand esSense by Neil Gains

2 responses so far

  1. Noise can be aesthetically pleasurable, and culturally significant–witness the Distortion pedal, or the texture of fur. We can contrast the Modernist project of removing aesthetic noise (Helvetica) with the Postmodern project of adding or revealing it (say, the Sex Pistols), and end up with a kind of slider, a continuum going from “all clean,” signal 1 : noise 0, to “all chaos,” signal 0 : noise 1.

    Is this useful for contemporary art and design, useful in communicating different sociocultural meanings? I hope so. I’m often drawn to texture, to noise, but often wonder why.

    What do you think aesthetic noise can signify?

  2. Andrew

    Thanks for your comments. I guess “noise” can be more interesting to the brain, perhaps because the signal is less clear and therefore needs more work to decode. Like you, I like interesting textures and sounds, and maybe an element of unpredictability can be aesthetically interesting. The work I have seen on the psychology of music suggests that much of the emotional effect is because of the anticipation (prediction) of particular outcomes and the way in which different music plays with this anticipation.

    Definitely an interesting topic


Leave a Reply