Risk Runners Presents

Street Math

Ten ISO 31010 risk assessment techniques, taught not in boardrooms — but on street corners, in dive bars, and across kitchen tables.

ISO 31010 : 2019 — Risk Assessment Techniques
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Risk analysis doesn't need a PowerPoint.

Every technique in ISO 31010 — from Bow Tie Analysis to Markov Chains — was built to help people make better decisions under uncertainty. But somewhere between the standard and the spreadsheet, the intuition gets lost.

Street Math puts it back. Each screenplay drops a real risk technique into an everyday scenario — a bouncer working the door, a mechanic sizing up a bad engine, a busker calculating which subway car to play. The math is real. The characters just speak it differently.

Ten techniques. Ten stories. Ten pages each.

The Screenplays

Click any card to read the full 10-page screenplay.

B.4.2 — Bow Tie Analysis
The Bouncer's Blueprint
A veteran bouncer explains club security to a rookie using bow tie analysis — mapping threats on the left, consequences on the right, and the bar brawl sitting in the middle. Preventative controls, reactive controls, and the escalation factors that break them.
B.9.3 — Decision Tree Analysis
The Hustler's Gambit
A street hustler maps out whether to pay off a supplier or dodge them — decision nodes, chance nodes, expected values, and the sensitivity analysis that proves the answer is robust even when the estimates are wrong.
B.5.10 — Monte Carlo Simulation
The Mechanic's Odds
A shady mechanic runs 100 mental simulations on a customer's engine — random variables for part wear, driving habits, and weather — to show why the "quick fix" has an 86% chance of catastrophic failure.
B.9.4 — Game Theory
The Roommate's Dilemma
Two roommates face the Prisoner's Dilemma when their landlord offers a deal to whoever snitches first. Payoff matrices, Nash Equilibrium, Tit for Tat, and the commitment device that changes the game entirely.
B.4.4 — Layers of Protection Analysis
The Heist Planner's Calculus
A meticulous heist planner breaks down a vault's independent protection layers — cameras, guards, biometrics, pressure alarms — calculating the probability of failure on demand for each to determine if the job's risk is tolerable.
B.3.3 — Ishikawa (Fishbone) Analysis
The Food Truck Meltdown
A food truck owner dissects a ruined lunch rush using the 6Ms — Methods, Machinery, Materials, Manpower, Measurement, and Management — tracing eleven causes back to three root failures.
B.8.4 — Pareto Charts
The Bartender's 80/20
A veteran bartender teaches a rookie that 80% of their revenue loss comes from just 20% of the causes — and why fixing the bathroom lock instead of slow service is the most expensive mistake in the business.
B.6.2 — Cross Impact Analysis
The Bookie's Web
A seasoned bookie explains how a star player's sprained ankle doesn't just change the game odds — it shifts the conditional probabilities of every connected prop bet. The money isn't in the obvious line; it's in the web.
B.9.2 — Cost/Benefit Analysis
The Loan Shark's Lesson
A loan shark walks a borrower through Net Present Value — showing how a "small" $50 weekly payment is actually a 1,160% annual rate, and why the credit union two blocks away is the rational choice.
B.5.9 — Markov Analysis
The Busker's Calculus
A subway saxophone player calculates transition probabilities between Good, Fair, and Failed train cars — building a Markov chain to figure out when to move, when to stay, and how long before transit police end the session.