Economics Quote by Donella H. Meadows
““Because we bump into reinforcing loops so often, it is handy to know this shortcut: The time it takes for an exponentially growing stock to double in size, the “doubling time,” equals approximately 70 divided by the growth rate (expressed as a percentage). Example: If you put $100 in the bank at 7% interest per year, you will double your money in 10 years (70 ÷ 7 = 10). If you get only 5% interest, your money will take 14 years to double.””
About This Quote
Source Book: Thinking in Systems, 2008
She explains the “doubling time” rule: time to double ≈70 divided by growth rate percentage.
In simple terms: Doubling time ≈70 ÷ growth rate%.
Key Takeaway
Use the rule to forecast growth.
Themes
systems
growth
exponential
Mood
educational
analytical
Type
technical
practical
When to use this quote
- investment planning
- resource management
- public policy
Key Concepts
economics
finance
population dynamics
Questions to Reflect On
- How does this rule apply to your field?
- What limits exponential growth?
A Different Perspective
Rule is an approximation, not exact.
