Signal-to-noise ratio is one of the fundamental principles of design, which is also relevant in the context of presentations.
It’s a concept that comes from telecommunications. In an information exchange system, signal-to-noise ratio is the relationship between the level of a desired signal and the level of background noise. The higher the ratio the better, because it means that the desired signal is more powerful than the background noise. In short, the signal is clearer.
The same concept applies to any type of design, including presentation design. In presentation design, signal-to-noise ratio is the relationship between the useful elements in a slide and the irrelevant ones. Here too it’s important that this ratio is as high as possible. The higher the ratio, the clearer the design and therefore the easier it is for an audience to understand it. The cognitive effort required to understand the design is small.
In order to create elegant slides, any decision to include (or to exclude) elements in a slide must be intentional. Whether it's a line, a chart, a table or an image—any element must contribute to communicating your message. Remember, each element is either a useful signal or background noise—and if it constitutes noise, it’s a distraction that should be removed.
The point here is not to make you become a telecommunications expert but to work on the power of your message. When designing slides, the question you should ask yourself is this: If I remove this element, does my message lose its effectiveness? If the answer is no, remove it.
If you want to learn more about how to make better presentations, download my report Top 7 Mistakes People Make When Creating Business Presentations.