Big Rocks Theory

The Big Rocks Theory is a metaphor for prioritisation popularised by Stephen R. Covey in First Things First. It suggests prioritising the most important things to be done first, or they would not be done at all.

The “rocks” represent different tasks, with the size of a rock proportional to importance. Covey looks at the task of filling a jar with as many rocks as possible, given the choice of some larger rocks, some pebbles, and some sand. If you start with the sand followed by the pebbles, there will be no more room left for the big rocks. If you start with the big rocks, then add the pebbles, and pour the sand last, the sand and the smaller stones will fill the gaps between the big rocks, and at least some big rocks will fit in.

Covey uses this metaphor to illustrate the importance of choosing a small number of “big rocks” for a product increment, making sure that they get achieved within the set time frame.

In Measure What Matters, John Doerr gives an example from YouTube, where Shishir Mehrotra used this metaphor to bring “focus to the whole company”, combining the Big Rocks Theory with Objectives and Key Results.

People did their own things and let a thousand flowers bloom, but no one could identify the top-level OKRs. Now leadership was saying “All of your ideas are wonderful. But could we please identify a few of them as our big rocks for this quarter and for the year? After that, everyone at YouTube knew our top priorities. All of our big rocks would make it into the jar.

By requiring stakeholders to choose only a small number of “big rocks”, this metaphor achieves a similar effect to Christmas prioritisation.

Learn more about the Big Rocks Theory