Signal-to-noise ratio

8 May 2023

Any data transmitting system has certain limited bandwidth, i.e. amount of useful information that it can pass through over certain period of time.

In real world, efficiency of any data transmitting system is always less than 100%. Say, certain system can transmit X amount of actual meaningful data per unit of time of total Y amount of data sent per same unit of time. Then signal-to-noise ratio would be X/Y. For example if 73% of data sent is actual meaningful data, that means that the rest 27% is either noise or just signal loss. Or, more realistically, vice versa. Anyway, amount of meaningful data transmitted is always less than 100% and ratio is always less than 1.

We can apply this to user interface as well. Since 'user interface' has a word 'interface' in it, that means that some kind of data transmission is happening. So, any user interface allows user input to pass through and provides some response back to the user. That is a signal. Along with signal always comes noise.

Designer's task is either to increase a fraction of signal or decrease a fraction of noise. In a nutshell, that's what any user interface is all about and that's the only reason why one would want to improve it. Any interface can be viewed through the prism of signal-to-noise ratio.

Potentially almost any change in user interface would affect this ratio. However, the designer should first take advantage of the improvements that provide the most value.