The knife-edge predecessor to Solow: growth from the saving rate and capital-output ratio.
Warming up the engine…
The pre-Solow growth model: with a fixed capital-output ratio, growth equals the saving rate divided by that ratio, a knife-edge with no self-correction.
g = s / v (saving rate over capital-output ratio)
If machines and output are locked in fixed proportions, saving mechanically buys growth, but any mismatch between warranted and actual growth spirals rather than heals. Solow's diminishing returns replaced the knife-edge with a stable steady state.
Use it to explain why 'financing-gap' aid models failed: v isn't constant and saving isn't destiny.
Now prove you have it
Move the curve to where you think it lands, and get told exactly which part you got right.
Real-world scenarios on this model
Equilibrium at g 4.0, s 16.
Equilibrium: g* = 4.0, s* = 16.0
Current equations
The first serious growth model. Growth needs investment, investment comes from saving, so growth equals the saving rate divided by how much capital each unit of output needs. The crossing shows the growth rate the economy's saving can support.