Knight 1921 — risk (known probabilities) vs uncertainty (unknown distributions); construction operates in uncertainty regime

Claim: Frank Knight's 1921 Risk, Uncertainty, and Profit introduced the foundational distinction: risk refers to outcomes with known or estimable probability distributions; uncertainty refers to outcomes whose distributions are themselves unknown. The distinction remains operative a century later.

Source: Knight, F. H. (1921). Risk, Uncertainty, and Profit.

Confidence: Verified (canonical text).

For Candid: Construction operates predominantly in the uncertainty regime — weather, lender behaviour, sub availability, scope drift, inspection timing rarely admit clean probability estimates. Prospect theory's machinery, calibrated on known-probability laboratory gambles, only approximately describes choice under genuine uncertainty.

Pitches that present clean expected-value calculations against a GC's actual choice problem will read as naïve. Owners experienced in construction know the probability inputs aren't reliable and discount the conclusion. This is part of why "ROI from marketing" projections fail to land — not because the GC is innumerate, but because he correctly recognizes the inputs are uncertainty-regime, not risk-regime, and the calculation therefore claims more precision than the data supports.