The one idea per slide rule

What the rule asks

The rule is about meaning, not word count. A slide can carry a chart with forty data points and still make one idea, such as costs doubled after the migration, if the headline says so and the chart proves it. A slide with four short bullets can carry four ideas and fail. Kevin Hale, a Y Combinator partner, puts it simply in his advice on pitch deck design: simple ideas are ones that are not intertwined with other ideas, a simple slide therefore expresses one idea, and while some ideas take more than one slide, you should try hard to express each point in one. His test is to show the slide to a stranger and ask what it means; if they do not immediately say the idea, the slide loses.

Why it works

Research on multimedia learning supports trimming slides to their point. Richard Mayer's coherence principle, set out in the Cambridge Handbook of Multimedia Learning, holds that people learn more deeply when extraneous material is excluded rather than included, even interesting material. A slide with one idea has less extraneous material by design. There is also a practical reason: when the slide and the speaker say the same one thing, the audience listens instead of reading ahead, and when the presenter moves to the next slide, the change itself signals that the idea has changed.

How to apply it

Write the point of each slide as a sentence before designing it. If the sentence needs an and, consider two slides. Use the headline to state the point, then choose the smallest amount of evidence that proves it: one number, one chart, one image, or a few short items. Move caveats, method notes and the second example into speaker notes or an appendix. More slides are not a problem in themselves; a twenty minute talk with thirty clear slides often runs more smoothly than one with twelve crowded ones, because each change of slide is quick to absorb.

Where the rule fails

The rule is written for presented slides. A deck sent to be read alone, such as an investor update or a board pre read, often needs several related points on one slide, because no presenter is there to walk through a long sequence. Dense reference slides, such as a pricing table or a specification comparison, carry many facts in service of one decision and are fine as long as the headline says what the reader should conclude. The rule also fails when applied mechanically: splitting a before and after comparison across two slides destroys the one idea it was meant to show.

Common mistakes

The first is counting words instead of ideas, so a slide technically passes a 6x6 rule while mixing three unrelated points. The second is a topic headline such as results, which forces the audience to work out the idea themselves. The third is splitting one idea across slides to meet a slide count. The fourth is treating the rule as a ban on data, producing slides so sparse they prove nothing. The fifth is moving everything into speaker notes and then reading the notes aloud, which recreates the crowded slide in spoken form.

Where it shows up in the product

Every text slot in a slide template here has a character budget, and the writing step is instructed to respect the minimum and maximum lengths and write less rather than truncate. Text also fits itself to its box, so a crowded slide shows its crowding as shrinking type, a useful warning sign. Speaker notes are rich text stored per slide and never shown on the slide, which gives the second idea somewhere to live. The conference talk example on this site keeps to one idea per slide across nine slides, including a single number on its own slide and six take home rules as short chips.

Questions people ask