The Pooley-Tupy theorem is an economics theorem which measures the growth in knowledge resources over time at individual and population levels.
Percentage Change in Knowledge Resources= \left(
Time Pricet | |
Populationt |
\right) ÷ \left(
Time Pricet+n | |
Populationt+n |
\right)-1
The theorem was formulated by Gale Pooley and Marian Tupy who developed the approach in 2018 in their paper: The Simon Abundance Index: A New Way to Measure Availability of Resources.[1] [2]
The theorem is informed by the work of Julian Simon, George Gilder, Thomas Sowell, F. A. Hayek, Paul Romer, and others.[3] [4] [5] [6] [7] [8]
Gilder offers three axioms; wealth is knowledge, growth is learning, and money is time. From these propositions a theorem can be derived: The growth in knowledge can be measured with time.
While money prices are expressed in dollar and cents, time prices are expressed in hours and minutes. A time price is equal to the money price divided by an hourly income rate.
Time Price=
Money Price | |
Hourly Income |
The Pooley-Tupy theorem adds changes in population as an additional variable in their formulation. In the case of an individual, population is equal to 1 at
t
t+n
If knowledge resources were being evaluated at the individual level and the time price was 60 minutes at
t
t+n
=(60 ÷ 45)-1
=1.33-1
=0.33=33%
If population at
t
t+n
=(60 ÷ 100) ÷ (45 ÷ 200)-1
=(.6) ÷ (.225)-1
=2.666-1
=1.666=166.6%
The Pooley-Tupy Theorem is part of an analytical framework that uses several other equations for analysis. This framework is described in their book, Superabundance: The story of population growth, innovation, and human flourishing on an infinitely bountiful planet.[9] [10] [11]
The percentage change in a time price over time can be expresses as:
Percentage Change in Time Price=
Time Pricet+n | |
Time Pricet |
-1
The resource multiplier indicates how much more or less of a resource the same amount of time can buy at two points in time.
Resource Multiplier=
Time Pricet | |
Time Pricet+n |
The percentage change in the resource multiplier is just the resource multiplier minus one.
Percentage Change in Resource Multiplier=Resource Multiplier-1
The compound annual growth rate or CAGR can be calculated as:
Compound Annual Growth Rate=Resource Multiplier1/n-1