My colleague Johannes recently mentioned the so called "70-20-10" rule in passing. Here is a quick breakdown.

It was initially developed to guide how people learn and grow at work.1 The researchers surveyed nearly 200 successful executives, asking them to identify the key events in their careers that made them more effective leaders. Based on the responses, they distilled the learning process into three categories:

Percentage Type of Learning Description
70% Challenging Assignments "On-the-job" experience, solving problems, and handling new responsibilities.
20% Developmental Relationships Learning through others.
10% Coursework & Training Formal education, seminars, and reading.

In the early 2000s, Eric Schmidt2 adapted the learning ratio into a strategic framework to ensure Google didn't lose its innovative edge while scaling its massive search business.

Percentage Type of Work Description
70% Core Business (e.g. Search, AdWords, Infrastructure) To sustain and improve the primary revenue drivers.
20% Adjacent Emerging Stars (e.g. Google Drive, Maps, Gmail) To scale products that have shown promise but aren't yet "core."
10% Radical Innovative Moonshots (e.g. Waymo, Project Loon, AlphaGo) To explore high-risk, high-reward ideas for the distant future.

  1. 1

    The CAREER ARCHITECT® Development Planner by Morgan McCall, Michael M. Lombardo and Robert A. Eichinger

  2. 2

    How Google Works by Eric Schmidt and Jonathan Rosenberg