1. Output metrics represent results and input metrics represent actions.

Output metrics is a scoreboard, and input metrics are like individual plays. To win the game you need to focus on the individual plays that drive the score. Monitor output metrics to know how you’re doing, but build experiments around the input metrics you can directly influence.

Output metrics help you set long term goals for the growth of your business. Examples:

• $6 million in revenue,
• 100k weekly active users
• $10 million in MRR

Input metrics represent the actions that influence the output metric. Example:

• 10,000 pageviews
• 1,200 registrations
• 700 upgrades to paid

You can’t focus exclusively on output metrics because they’re too big, too broad, and not actionable.

Spotify as an example

2. Output Metrics Are a Lagging Indicator

Input metrics are leading indicators and output metrics are lagging indicators.

By definition, it can take time for the output to reflect positive or negative changes in the inputs.

Here’s an example:

Revenue retention is the output of engaged users. The usage is the input, and looking only at revenue retention has two big problems: