Example models for ModelRisk and ModelChoice
Risk Analysis Example Models in Excel
139 worked models, each built around a real business question: a cost contingency, a drug’s risk-adjusted NPV, an insurer’s capital, whether to drill. Each page opens with the model’s answer, so you can see what it does before you download it.
Max complexityAny
Projects and construction 9 models
- ModelRisk★★★★★Cost Estimate with ContingencyHow much contingency does the warehouse budget need?Twelve cost items with three-point ranges added up by simulation: the simplest useful risk model.
- ModelRisk★★★★★Rework and Change OrdersIs a 5% change allowance enough?Three classes of change, each a random number of events with random costs, added up with VoseAggregateMC.
- ModelRisk★★★★★Risk Register: Threats and OpportunitiesHow much risk contingency does the hospital extension need?A risk register turned into a simulation: risk events with linked cost and schedule impacts.
- ModelRisk★★★★★Bid Pricing: Margin versus Chance of WinningWhat markup should we bid?Eleven bid prices evaluated on the same simulated costs and competitor bids, with a winner's-curse effect.
- ModelRisk★★★★★Material Price Escalation and Procurement StrategyBuy the steel now, as needed, or with a price cap?Monthly steel and concrete price paths over 18 months and four ways of buying the steel, on the same paths.
- ModelRisk★★★★★Schedule Risk on a Project NetworkWhen will the new bridge open?A 15-activity network with three-point durations and a risk event, scheduled forwards and backwards in every iteration.
- ModelRisk★★★★★Construction Cash Flow and Peak FundingIs a US$40 million facility enough?A 48-month cash flow with S-curve spend, off-plan sales and a revolving facility with monthly interest.
- ModelRiskOptimizer★★★★★Schedule Acceleration Chosen by the OptimizerWhich activities should be accelerated, at least cost, for an 80% chance of opening the bridge within the contract?A 15-activity network scheduled in every iteration; six yes-or-no accelerations chosen by the Optimizer for an 80% chance of finishing in time.
- ModelRisk★★★★★Integrated Cost and Schedule RiskBudget and completion date together: how confident can the sponsor be of both, for the treatment works upgrade?Schedule, time-dependent costs and shared risk events simulated together, with the joint chance of meeting budget and date.
Also in this area, in the earlier format:
- Cost Contingency Worked Example The €12 million worked example behind the cost contingency guide.
- Missile Development Cost Estimation A cost risk model in the style of the US Air Force cost risk and uncertainty handbook.
Corporate finance 14 models
- ModelRisk★★★★★Investment Appraisal of a New Production LineThe business case says invest. What does the risk say?Ten years of cash flow from five three-point estimates; NPV, IRR and payback.
- ModelChoice★★★★★Venture Capital Investment DecisionAfter 18 months, put $2 million into the next round or pass?Four decisions and five chance events. Best first decision: Invest $2M, expected value $4.2m.
- ModelRisk★★★★★Company Valuation with Terminal-Value UncertaintyIs the price right?A five-year DCF with a terminal value, two ways; growth and margin correlated through a copula.
- ModelRisk★★★★★Currency and Interest-Rate ExposureHow much cash could currency and interest-rate moves cost, and how much does hedging half of it save?Three correlated market prices simulated together (VoseTimeMultiGBM) over twelve quarters; a hedging policy.
- ModelRisk★★★★★Portfolio Value at Risk and Expected ShortfallHow much could the reserve portfolio lose in a bad year?Two models of the same portfolio — Normal, and fat-tailed with a Student copula — compared in the tail.
- ModelRisk★★★★★Sales Forecast for a New ProductWill the launch reach its business plan?Two expert time series: adoption in a finite market, and consumables per analyser year by year.
- ModelRisk★★★★★Credit Portfolio LossesHow much could the loan book lose in a bad year?Defaults in five rating grades driven by one economic factor (Vasicek), and a random loss for every default.
- ModelRiskOptimizer★★★★★Investment Portfolio Chosen by the OptimizerWhich mix of equities, bonds and real estate earns most while the one-year 95% value at risk stays within the policy's limit?Fat-tailed returns joined by a Student copula; four weights chosen by the Optimizer for the highest mean return within a value-at-risk limit.
- ModelChoice★★★★★Distressed Debt InvestmentBuy the senior secured debt, the unsecured debt, a credit default swap, or take no position?Three decisions and 14 chance events. Best first decision: Credit Default Swap ($5M Premium), expected value $23.3m.
- ModelChoice★★★★★M&A Acquisition DecisionA hostile takeover, a friendly merger, a 30% minority stake, or no deal?Three decisions and 17 chance events. Best first decision: Friendly Merger ($1.5B), expected value $663.2m.
- ModelChoice★★★★★Private Equity BuyoutA full buyout at 8x EBITDA, a buyout at 6x with management rollover, a growth minority stake, or pass?Seven decisions and 12 chance events. Best first decision: Buyout at 6x + Mgmt Rollover ($300M), expected value $278.5m.
- ModelChoice★★★★★Sovereign Wealth Fund AllocationHow should a fund invest $5 billion for ten years: growth, balanced, defensive or infrastructure-heavy?Three decisions and 23 chance events. Best first decision: Growth Portfolio, expected value $7.33bn.
- ModelRisk★★★★★Real Options: Expand or AbandonBuild big now, or start small and decide later?Three investment strategies on the same simulated demand paths; a decision rule to expand or abandon applied inside every iteration.
- ModelRisk★★★★★Three-Statement Forecast and Funding RiskWill the company stay within its bank covenants?Five years of linked income statement, balance sheet and cash flow, with a revolver, dividends and covenant tests in every iteration.
Also in this area, in the earlier format:
- NPV Probability Analysis A ten-year cash flow turned into the full NPV distribution and the chance of a loss.
- Largest Loss from Fraud The capital a bank needs to cover its largest fraud loss.
Insurance 10 models
- ModelRisk★★★★★Aggregate Claims: Frequency × SeverityWhat will a year's claims cost?A year's claims as a random number of random claim sizes, three ways — two right and one common mistake.
- ModelRisk★★★★★Pricing a Policy: Premium PrinciplesTwo policies cost the same on average — should they cost the same to insure?Two policies with the same expected claims, priced four ways: the risk loading is what tells them apart.
- ModelRisk★★★★★Fitting Claim Frequency and Severity to DataWhich distributions fit the claims history — and how much does the shortness of that history add to the risk?Distributions fitted to ten years of claim counts and 250 claims, compared by SIC, used with and without parameter uncertainty.
- ModelRisk★★★★★Life Portfolio and LapseWhat is a block of life policies worth, and what makes it uncertain — chance, or not knowing the rates?Twenty thousand policyholders moving between four states each year: a Markov chain, with and without uncertainty in the rates.
- ModelRisk★★★★★Reinsurance Programme: Excess of Loss and Quota ShareWhat does reinsurance cost, and what does it buy?Every claim split between the insurer and two excess-of-loss layers, a quota share on top; four programmes compared on the same claims.
- ModelChoice★★★★★Insurance Product LaunchLaunch cyber insurance nationwide, in three states, through an MGA partner, or not at all?Three decisions and 12 chance events. Best first decision: Limited Launch (3 States), expected value $3.2m.
- ModelRisk★★★★★Catastrophe and Large-Loss TailHow large is the 1-in-200 year loss when the history covers only 25 years?Extreme value theory on 25 years of loss events: a threshold, a Generalised Pareto tail, and return periods far beyond the data.
- ModelRiskOptimizer★★★★★Reinsurance Programme Chosen by the OptimizerWhich retention, cover and quota share keep the 1-in-200 loss within the capital at the least cost?Each year’s claims added up in bands so any layer is priced exactly; the retention, cover and quota share chosen together by the Optimizer.
- ModelChoice★★★★★Life Insurance Portfolio AcquisitionBuy a large or a small block of life policies, invest through a fund, or not invest?Two decisions and 12 chance events. Best first decision: Buy Large Portfolio (1000), expected value $27.8m.
- ModelRisk★★★★★Capital Requirement and DiversificationHow much capital does an insurer need, and how much does diversification save?Five risks joined by copulas, capital at the 1-in-200, the square-root formula, and two ways of sharing the capital out.
Also in this area, in the earlier format:
- Runoff of Outstanding Claims A runoff simulation of the claims still to be paid from an insurance fund.
- Tranched Insurance Policy Payout The aggregate payout from a policy split into tranches.
Oil and gas 17 models
- ModelRisk★★★★★Volumetric Resource EstimateHow much gas and condensate could the Falcon discovery hold?One calculation sheet: a chain of multiplications with expert ranges on every input.
- ModelRisk★★★★★Chance of Success with Shared RiskOne well, two stacked targets that share the same source rock. What are the real chances of success, and what is the well worth?Dependent chance factors: one shared risk and two independent ones, with risked volumes and value.
- ModelRisk★★★★★Hedging Production with Swaps and CollarsSwap, collar or puts?Monthly price paths and production with outages, and four hedging strategies compared on the same paths.
- ModelRisk★★★★★Major Accident and Operational Loss ExposureWhat could our operations lose in a year, and which insurance programme is worth its premium?Frequency × severity losses from frequent small incidents to a rare major accident, and insurance per occurrence.
- ModelRisk★★★★★Production Forecast with Decline UncertaintyHow much more will well K-12 produce?Fits a decline to production history, carries the uncertainty of the fit into the forecast and adds a risk event.
- ModelRisk★★★★★Well Cost and Time (AFE)What should the AFE for well K-15 be?Phase-by-phase well estimate with trouble time as a frequency × severity sum and two major risk events.
- ModelChoice★★★★★LNG Export Terminal InvestmentBuild a full-scale LNG export terminal, a modular first phase, a floating unit, or nothing?Two decisions and ten chance events. Best first decision: Build Modular (Phase 1), expected value $1.32bn.
- ModelChoice★★★★★Shale Gas Development DecisionDevelop the whole pad, drill two delineation wells first, sell the acreage, or wait?Four decisions and nine chance events. Best first decision: Delineation Wells First (2 Wells), expected value $21.8m.
- ModelRisk★★★★★Exploration Portfolio with Shared Play RiskWhich wells should we drill next year?Compares drilling programmes built from eight prospects whose success depends on shared play risk.
- ModelRisk★★★★★Exploration Prospect EconomicsShould we drill the exploration well?Several sheets, correlated inputs, a risk event, a stochastic price path and a 30-year cash flow.
- ModelRisk★★★★★Field Development Concept SelectionTieback, FPSO, or start small and expand?Three 25-year development cash-flow models on common random numbers, with a decision rule inside the simulation.
- ModelRiskOptimizer★★★★★Hedging Programme Chosen by the OptimizerHow much to swap, how much to protect with puts, and at which strike, to meet the budget at the least cost?Monthly price paths and production outages; the swap share, put share and strike chosen by the Optimizer within a limit on missing budget.
- ModelRisk★★★★★Oil Price Forecast from HistoryWhich price deck should the five-year plan use?Fits three time-series models to price history, weighs them by the evidence and averages their forecasts.
- ModelChoice★★★★★Mature Oil Field: Enhanced Oil Recovery DecisionFor a mature oil field: CO₂ injection, water alternating gas, a polymer pilot, primary recovery, or decommissioning?Three decisions and 11 chance events. Best first decision: Continue Primary Recovery, expected value $48.0m.
- ModelChoice★★★★★Offshore Drilling Campaign DecisionDrill an exploration well now, shoot 3D seismic first, farm out the licence, or give it up?Six decisions and 14 chance events. Best first decision: Acquire 3D Seismic First, expected value $40.0m.
- ModelChoice★★★★★Refinery Upgrade DecisionAdd a coker, upgrade the hydrotreater, convert to biofuels, or sell the refinery as it is?One decision and 13 chance events. Best first decision: Full Coker Addition ($800M), expected value $795.6m.
- ModelRiskOptimizer★★★★★Exploration Portfolio Chosen by the OptimizerWhich wells should we drill next year?The programme with the highest expected value within the budget and the risk limit, chosen by the Optimizer.
Also in this area, in the earlier format:
- Oil in Place (OOIP) and Reserves The OOIP formula worked through by simulation: P90, P50 and P10 reserve estimates.
Pharmaceuticals and biotech 15 models
- ModelRisk★★★★★Clinical Trial Cost and DurationWhat budget and what date for the top-line results?Three-point estimates and three risk events, patients grossed up for dropouts, and a running cost that turns every delay into money.
- ModelRisk★★★★★Batch Yield and Manufacturing CapacityHow many batches must we plan to make enough drug substance for the launch year?Batch failures from a Beta fitted to the plant’s record and a yield for every batch: the chance of meeting demand for each campaign size.
- ModelRisk★★★★★Bayesian Estimate of a Trial's Success ProbabilityHalfway through a Phase II trial: how likely is it to succeed — and should it stop, or carry on?A Beta prior updated with the interim data: the predictive chance that the final analysis succeeds, simulated and exact.
- ModelRisk★★★★★Drug Development Risk-Adjusted NPVWhat is a compound in Phase II worth — and should we develop it ourselves or license it out?Phases with uncertain cost, time and success, then launch and patent expiry: the textbook rNPV against the simulated NPV.
- ModelRisk★★★★★Launch Sales Forecast: Peak Sales and UptakeHow big will the new drug be?A patient funnel, an expert’s uptake curve as a correlated time series, and a competitor that may enter: peak sales against plan.
- ModelRisk★★★★★Patient Recruitment and Trial TimelinesWhen will the last patient be enrolled — and how many sites does it take to be confident of the deadline?Sixty sites, each with its own opening time and recruitment rate: a Poisson–Gamma model of enrolment, month by month.
- ModelChoice★★★★★Clinical Trial Go/No-Go DecisionAfter Phase I: run Phase II, partner the compound, or shelve it?Four decisions and eight chance events. Best first decision: Proceed to Phase II, expected value $135.1m.
- ModelChoice★★★★★Pharmaceutical Pipeline DecisionDevelop drug A, drug B or both, out-license both, or keep the money?Three decisions and ten chance events, driven by linked inputs. Best first decision: Develop Both (Parallel), expected value $776.7m.
- ModelRiskOptimizer★★★★★Cold-Chain Vaccine Micro-DepotHow many coolers and backup batteries per depot keep temperature excursions to essentially zero?Sizes coolers and backup batteries at four depots at the lowest capital cost, with no temperature excursions in 90% of runs.
- ModelChoice★★★★★Biosimilar Launch Strategy DecisionLaunch a biosimilar at risk, wait for a patent settlement, license it in, or stay out of the market?Three decisions and 13 chance events. Best first decision: At-Risk Launch, expected value $130.0m.
- ModelChoice★★★★★Gene Therapy Development DecisionDevelop an in-vivo or an ex-vivo gene therapy, license it to big pharma, or shelve the programme?Four decisions and 12 chance events. Best first decision: Ex-vivo Cell Therapy, expected value $187.9m.
- ModelChoice★★★★★Vaccine Platform Investment DecisionInvest in an mRNA platform with a lead vaccine, the platform alone with a partner, one licensed candidate, or nothing?Three decisions and 14 chance events. Best first decision: Full Platform + Lead Candidate, expected value $538.2m.
- ModelRisk★★★★★Exposure Variability: Dose Selection with PK/PDWhich dose keeps most patients between the effective level and the safety limit?A PK model solved for every simulated patient, four dosing regimens and between-patient variability, against a therapeutic window.
- ModelRiskOptimizer★★★★★R&D Portfolio Chosen by the OptimizerWhich projects to fund for the most value, with limits on budget risk and on the chance of no launch?Eight projects with phase-by-phase attrition and correlated Phase II results; the portfolio chosen by the Optimizer from 256 combinations.
- ModelRisk★★★★★R&D Portfolio: Which Projects to FundEight projects, one budget: which to fund for value, for a steady pipeline, and within the money we have?Eight projects with phase-by-phase attrition and correlated Phase II results; four portfolios compared on value, launches and budget.
Manufacturing 12 models
- ModelRisk★★★★★Production Yield and ScrapHow many parts must we make to deliver 4,800 good ones?A defect rate known only from a sample, a Binomial number of defects, and the run size that meets an order.
- ModelRisk★★★★★Tolerance Stack-Up and Process CapabilityWill the assembly's gap stay within specification?Five part dimensions add up to one gap: worst case, root-sum-square and Monte Carlo against the specification.
- ModelRiskOptimizer★★★★★Inventory Policy Chosen by the OptimizerWhich reorder point and order quantity cost least while keeping the service the customers were promised?Demand over a random lead time as an aggregate; the reorder point and order quantity chosen together by the Optimizer for a service target.
- ModelRisk★★★★★Inventory Policy under Uncertain Demand and Lead TimeWhen should we reorder?Demand during a random lead time as an aggregate, the service level of each reorder point, and its cost.
- ModelRisk★★★★★Reliability and Availability of a Production LineHow often will the line stop, what does it cost, and is a standby machine worth it?Four machines in series, each failing and being repaired at random through the year; one fitted to its failure records.
- ModelRisk★★★★★Spare Parts and Maintenance StrategyRun to failure or replace on a schedule — and how many spare kits to hold?Every bearing replaced when it fails or at a set age: four strategies on the same simulated lives, and the spare kits each needs.
- ModelRisk★★★★★Warranty Cost ForecastWhat will this year's sales cost in warranty claims, and when?A year's sales, each quarter failing at random through a two-year warranty: claims by quarter and the reserve.
- ModelChoice★★★★★Supply Chain Resilience DecisionA nearshore second source, a better offshore supplier, vertical integration, or the status quo?Three decisions and ten chance events. Best first decision: Single Offshore Supplier, expected value $12.1m.
- ModelRisk★★★★★Capacity Expansion DecisionHow many presses should we add?Sixty months of seasonal, uncertain demand against four capacity options with overtime, subcontracting and lost sales.
- ModelRiskOptimizer★★★★★Spare Parts and Maintenance Strategy Chosen by the OptimizerWhich replacement age and how many spare kits cost least while keeping the downtime promised to a customer?Bearing lives simulated on every spindle; the replacement age and spare kits chosen together by the Optimizer within a limit on downtime.
- ModelRisk★★★★★Supply-Chain DisruptionWhat do supplier disruptions cost us, and which protection pays?Random disruptions at four suppliers and a regional disaster; safety stock, a second source and insurance compared.
- ModelRiskOptimizer★★★★★Ceramics Studio: Kiln Firing AssignmentWhich kiln should fire each ware batch so no single kiln carries the peak energy load?Assigns 15 batches to five kilns so the mean peak energy draw is as low as possible.
Energy and utilities 6 models
- ModelChoice★★★★★Water Treatment PlantA new membrane plant, an upgrade, local systems or a regional partnership: which costs least?One decision and four chance events, driven by linked inputs. Best first decision: Upgrade Existing Plant, expected cost $71.7m.
- ModelChoice★★★★★Wind Farm PortfolioBuild the onshore wind farm, the offshore one, both, or sell the development rights?One decision and three chance events, driven by linked inputs. Best first decision: Hybrid Portfolio (Both), expected value $440.3m.
- ModelChoice★★★★★Renewable Energy Project SelectionA 50 MW solar farm, a 30 MW wind farm, solar with storage, or no project?One decision and 12 chance events. Best first decision: Hybrid Solar+Storage, expected value $4.9m.
- ModelRiskOptimizer★★★★★Desalination Plant: Antiscalant DosingHow much antiscalant should each reverse-osmosis train receive when feed salinity is uncertain?Sets antiscalant doses for six reverse-osmosis trains at the lowest mean daily cost, with 95th-percentile brine toxicity within the permit.
- ModelRiskOptimizer★★★★★Micro-Grid: Single-Period Economic DispatchHow much power to draw from each source to maximise expected margin within the feeder and emissions limits?Dispatches power from four sources for the highest mean margin, within limits on grid import and emissions.
- ModelRiskOptimizer★★★★★Wastewater Aeration: Blower StagingHow many blower steps per basin minimise the worst-case energy bill while keeping oxygen safe 95% of the time?Stages the blowers in four basins to cut the worst 10% of energy bills, keeping oxygen above 2.0 mg/L with 95% assurance.
Agriculture and food 10 models
- ModelChoice★★★★★Agricultural IrrigationShould a 640-acre farm install centre-pivot, drip or upgraded flood irrigation, or stay rain-fed?One decision and four chance events, driven by linked inputs. Best first decision: Center Pivot System, expected value $6.1m.
- ModelChoice★★★★★Franchise ExpansionGrow a three-restaurant chain with company stores, single franchises, a master franchise, or not at all?One decision and three chance events, driven by linked inputs. Best first decision: Sell Franchises, expected value $6.3m.
- ModelRiskOptimizer★★★★★Craft Bakery: Sourdough HydrationWhat hydration percentage yields the target crumb structure?Finds the dough hydration, between 60% and 90%, that puts the crumb index on its target of 3.2.
- ModelRiskOptimizer★★★★★Greenhouse: CO₂ Enrichment vs CostWhat CO₂ set-point maximises yield without breaching the daily enrichment budget?Finds the CO₂ set-point with the highest mean yield, with enrichment costing no more than $150 a day.
- ModelRiskOptimizer★★★★★Specialty Coffee: Espresso Extraction TimeWhat single shot time gives the best expected cup score?Finds the espresso shot time, between 18 and 40 seconds, with the best mean cup score.
- ModelChoice★★★★★Agricultural Crop Planning DecisionShould a 500-acre farm plant corn, plant soybeans, split the land 50/50 or lease it out?Two decisions and ten chance events. Best first decision: Plant Corn, expected value $61,350.
- ModelChoice★★★★★Restaurant Chain Expansion DecisionExpand with a company-owned flagship, franchises, a ghost kitchen, delivery only, or not at all?Three decisions and nine chance events. Best first decision: Company-Owned Flagship, expected value $155,250.
- ModelRiskOptimizer★★★★★Aquaculture: Daily Feed PulsesHow many feed pulses per pen give a robust harvest weight without risking an oxygen crash?Sets feed pulses for five fish pens to raise the 25th-percentile harvest, with at most a 5% chance of an oxygen crash.
- ModelRiskOptimizer★★★★★Vertical Farm: Crop Rack AllocationHow many grow-racks should each crop get to maximise expected profit within the light and water budgets?Splits grow-racks among four crops for the highest mean profit within a 4,000 kWh lighting and 2,600 L water budget.
- ModelRiskOptimizer★★★★★Vineyard Frost ProtectionHow many protection units per block keep every bud above the frost-damage line on a cold night?Places frost protection units across five vineyard blocks at the lowest mean cost, with at most a 10% chance of frost damage.
Other industries 18 models
- ModelChoice★★★★★Data Center BuildBuild a Tier IV or a Tier III data centre, lease colocation space, or move to the cloud?One decision and four chance events, driven by linked inputs. Best first decision: Colocation Partnership, expected cost $14.1m.
- ModelChoice★★★★★Fleet ElectrificationConvert a 100-vehicle diesel fleet to electric all at once, in phases, in part, or not at all?Two decisions and four chance events, driven by linked inputs. Best first decision: Hybrid Fleet (30% EV), expected value $1.1m.
- ModelChoice★★★★★Hospital Equipment DecisionBuy premium or standard imaging equipment, lease it, or share it with a partner hospital?Two decisions and four chance events, driven by linked inputs. Best first decision: Buy Premium Equipment, expected value $44.8m.
- ModelChoice★★★★★Retail Store RolloutOpen 50 stores at once, pilot 10 first, open one flagship, or stay put?Two decisions and four chance events, driven by linked inputs. Best first decision: National Rollout (50 stores), expected value $83.0m.
- ModelChoice★★★★★Software Platform Build vs BuyBuild a software platform, buy a licence, buy and customise one, or use open source?Two decisions and four chance events, driven by linked inputs. Best first decision: Buy Commercial License, expected value $9.4m.
- ModelChoice★★★★★Startup Product Launch DecisionLaunch a new software product at full scale, launch a minimum viable product first, or not launch?Three decisions and four chance events. Best first decision: Launch MVP, expected value $178,200.
- ModelChoice★★★★★Airline New Route DecisionLaunch a new route with a daily wide-body, a daily narrow-body, a test three times a week, or not at all?Three decisions and eight chance events. Best first decision: Daily Narrow-Body, expected value $3.6m.
- ModelChoice★★★★★Cybersecurity Investment DecisionA full security suite, basic protection, insurance only, or accept the risk: which costs least overall?Three decisions and eight chance events. Best first decision: Cyber Insurance Only, expected cost $225,000.
- ModelChoice★★★★★EdTech Platform Launch DecisionBuild an online learning platform, partner with a university, run a marketplace, or not launch?Two decisions and nine chance events. Best first decision: Marketplace Model, expected value $1.9m.
- ModelChoice★★★★★Mining Exploration DecisionExplore the site in full, explore it in phases, or sell the exploration rights?Four decisions and seven chance events. Best first decision: Phased Exploration, expected value $15.6m.
- ModelChoice★★★★★Movie Studio Greenlight DecisionGreenlight a big-budget original, a mid-budget franchise film, a low-budget indie, or nothing?Two decisions and seven chance events. Best first decision: Mid-Budget Franchise, expected value $74.5m.
- ModelChoice★★★★★Real Estate Development DecisionDevelop the site for housing or for offices and shops, buy it and hold it, or not buy?Two decisions and eight chance events. Best first decision: Buy & Develop Commercial, expected value $798,000.
- ModelRiskOptimizer★★★★★Radiotherapy: Beam-Weight PlanWhat beam weights maximise a robust (P10) tumour dose while keeping the organ within tolerance 95% of the time?Weights five radiotherapy beams to raise the tumour’s 10th-percentile dose, with at most a 5% chance of overdosing the organ at risk.
- ModelRiskOptimizer★★★★★Snowmaking: Gun AllocationHow many snow guns per slope open most of the mountain on a marginal cold night at least cost?Spreads snow guns over six slopes at the lowest water and power cost, with five slopes open with 90% assurance.
- ModelRiskOptimizer★★★★★Stadium Egress: Gate-Lane StaffingHow many lanes to open at each gate so the crowd clears within 8 minutes on 95% of nights?Staffs the lanes at six gates at the lowest mean cost, so the crowd clears within eight minutes on 95% of nights.
- ModelRiskOptimizer★★★★★Museum: Exhibit Tour SequencingWhich viewing slot should each exhibit occupy so the crowd spreads evenly through the day?Assigns 14 exhibits to eight tour slots so the crowd is as even as possible through the day.
- ModelRiskOptimizer★★★★★Parcel Hub: Sorter Chute BalancingWhich chute should each parcel go to, so the busiest chute finishes as early as possible?Assigns 16 parcels to six sorter chutes so the busiest chute finishes as early as possible.
- ModelRiskOptimizer★★★★★Render Farm: Frame DistributionWhich render node should each shot go to, so the busiest node finishes as early as possible?Assigns 20 shots to six render nodes so the busiest node finishes as early as possible.
General techniques 28 models
- ModelRisk★★★★★Sales in a Limited MarketHow do sales behave when the market is limited?Two simple ways to keep a sales forecast inside its market: a pool of buyers that runs down, and a ceiling.
- ModelRisk★★★★★A Step Change in the Event Rate (Projected Cures)How many lives will a cure save if nobody knows when it will arrive?A Poisson series with a trend, thinned by a binomial from an uncertain month on.
- ModelRisk★★★★★Bounded Random WalkWhat does a growing, volatile series look like when practical limits hold it in?A lognormal random walk held between a rising cap and a falling floor, each period starting from the bounded value.
- ModelRisk★★★★★Cascading RisksHow much do the links between risks add to the contingency?A risk register in which some risks make others more likely or worse: a few IF formulas on top of risk events.
- ModelRisk★★★★★Correlation Through a Common Factor (Look-up Table)How much later does a project finish when bad weather hits every activity at once?One shared random factor and a look-up table make six durations move together, without a correlation matrix.
- ModelRisk★★★★★Counts of Random Events with Trend and SeasonalityHow many car crashes will there be next year, week by week?A weekly Poisson series whose rate follows a trend, a seasonal pattern and a possible step change.
- ModelRisk★★★★★Envelope Correlation: Interest and Mortgage RatesHow do you make one variable follow another when you only know its range at a few points?Correlating two variables from expert ranges: the second's range follows the first.
- ModelRisk★★★★★Event Counts over Time: Poisson and PólyaHow uncertain is next year's total of house calls?The same expected counts with three amounts of randomness: Poisson, and two ways of adding Pólya's extra variation.
- ModelRisk★★★★★Forecast from a Leading IndicatorCan this year's building permits forecast next year's cement sales?A regression on a lagged indicator: find the lead, fit the line, forecast with the residual scatter.
- ModelRisk★★★★★Precision Control: How Many Samples Are EnoughHow precisely does a simulation know its mean, spread, percentiles and probabilities, and how many samples does each need?A small cash-flow model; the point is the precision of its results and the samples each answer needs.
- ModelRisk★★★★★Probability of RuinCould this year's risks ruin the company?Ten risk events with fixed costs: the chance that their total ruins the company, simulated and exact.
- ModelRisk★★★★★Random Sales with a Competitor That May EnterWhat is it worth to keep a competitor out?Poisson sales around a growing trend, cut by a competitor that may or may not enter, at an uncertain month.
- ModelRisk★★★★★Sampling from a Population of Several GroupsTake 30 balls from a bag of 100 in five colours: how many of each will you get?One array function draws the whole sample; a second one shows what putting balls back would change.
- ModelRisk★★★★★Simple Project Schedule with RisksWhy does a project built from most-likely durations finish late?A small network of activities with uncertain durations, parallel paths, risk events and alternative ways of working.
- ModelRisk★★★★★Tornado of a Percentile: What Drives a Bad YearWhat drives the downside of the profit, not just its average?One year of a copper mine's profit from six uncertain inputs; the percentile tornado tables come from array formulas.
- ModelRisk★★★★★Tornado of the Mean: What Drives the ProfitWhich uncertainties move the expected profit, and by how much?One year of a plant's profit from seven uncertain inputs; the tornado table and chart come from one array formula.
- ModelRisk★★★★★Bayesian Model AveragingWhen the data cannot tell which model is right, keep them all, weighted by how well each fits.Fitting several candidate models and mixing them by how well each explains the data; three kinds of model.
- ModelRisk★★★★★Credit Portfolio Losses Two WaysA year's default losses: simulated, built by Fast Fourier Transform, and summed product by product.Two portfolios, each modelled two ways that must agree; VaR and expected shortfall without simulation noise from the FFT.
- ModelRisk★★★★★Extremes of Many Random VariablesThe largest and the smallest of 10,000 independent values, without sampling all 10,000.Sampling the largest or smallest of thousands of values directly, checked against the exact formula and against sampling them one by one.
- ModelRisk★★★★★From a Survey to Probabilities: an Election1,027 voters asked: how sure can we be who wins, and which alliance wins?The Dirichlet distribution turns survey counts into uncertain shares; questions become simple 1/0 outputs.
- ModelRisk★★★★★Markov Chains: Marital Status in 25 YearsWhere will a group of 100 people be in 25 years?A population moving between four states each year, simulated two ways and checked against the exact expectation.
- ModelRisk★★★★★Moments of an Aggregate DistributionThe mean, spread, skewness and kurtosis of a year's total claims, without simulating, and what they are good for.Exact moments of a random sum, and distributions matched to them, checked against simulation.
- ModelRisk★★★★★Pólya Regression Fitted to Accident DataHow many sports accidents next year, and the two after?A count regression fitted by maximum likelihood, projected with and without the uncertainty in its parameters.
- ModelRisk★★★★★Risk Portfolio: The Central Limit Theorem ApproximationCan a register of 132 risks be added up without a simulation?The mean and variance of risk events, and the Central Limit Theorem checked against a simulation.
- ModelRisk★★★★★Correlated Insurance PoliciesFive lines of policies whose bad years come together: what correlation does to the total.Five lines of claims with deductibles and limits, linked by a Clayton copula, against the same lines taken as independent.
- ModelRisk★★★★★Operational Risk Capital (FFT)How much capital covers a year of operational losses at 99.9%?Forty-five frequency–severity cells combined by FFT into one annual loss: the 99.9th percentile and capital by risk type.
- ModelRisk★★★★★Profits from Expanding Investments (TV Series)Where does a TV studio's profit come from?A chain of random counts (pilots, series, US sales, seasons) and profits summed over random numbers of draws.
- ModelRisk★★★★★Missile Flight: Differential EquationsA missile with air friction: where does it land, how sure are we, and what friction do the observations imply?Four differential equations solved in every simulation, the landing found without Solver, and the friction fitted to observations.
Also in this area, in the earlier format:
- Distributed Market Share Sales as competitors enter and the market share is shared out.
- Nearest Neighbour Distance The distance to the nearest of a set of events scattered at random in space.
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How the models are built
Each ModelRisk workbook opens on an About sheet with the business question, a map of the sheets and its assumptions. The Inputs sheet holds every assumption with its range and its basis, the calculation sheets follow, and the Results sheet answers the question with tables and charts that fill in from the last simulation.
Each ModelChoice example holds a decision tree on its own sheet, with the problem, the options and the key assumptions beside it. ModelChoice rolls the tree back to the best decision at every step.
- Read before you download. Every page shows the model’s answer, its inputs and its limitations.
- Start simple. Complexity runs from one star to five: set Max complexity to see only the models you are ready for.
- Find a technique. Choose a distribution or a feature under Uses to see every model that uses it.
- The figures are illustrative. The companies, projects and numbers are invented for teaching.
Run any of them yourself. The Monte Carlo models need ModelRisk and the decision trees need ModelChoice, both add-ins for Excel. Each has a free 15-day trial.
Built a model others could learn from? Tell us about it. We look at every proposal, rebuild the good ones in this format with you, and credit you on the page.
Propose a modelLast updated 30 October 2026.