When should a builder order long-lead materials once holding them costs money?

What it found

Extends the house-schedule Monte Carlo (3,000 builds per row) with the cost of material that arrives before it is used: a financed deposit, storage and handling, and damage or theft. Ordering each material about two lead times before its planned start cuts the build from 214 to 182 working days and interest plus holding cost from 3.34% to 2.91% of price. Ordering everything on day 0 saves more days (151) but costs 4.00%, worse than the baseline. The cheapest order time moves from three lead times (free to hold) to 1.5 (expensive to hold). Stylised: every cost is assumed and the order plan is fixed from the baseline schedule.

A figure from its own output

Paper, code and results

• README and method
• Experiments and results
• Code
• Tests

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Other research topics

Proper scoring & elicitation28Effort & peer prediction9Verification games & slashing19Detection & tolerances14Markets as routers13Prediction-market design9Paying contributors8Decentralised training systems23Digital twins & sim-to-real164LLM chip design loops40Robot manufacturing loops53Ambient AI assistant46Self-replicating manufacturing34Simulation-first design64Engineered clothing45Task-specific AI accelerators40Algorithmic chip-design loops42Open-source purpose-built robots44The software-engineering loop43Adversarial human imitation41Open-source residential construction41Autonomous multi-angle capture34Sensing, imaging and 3D31Energy supply and dense energy storage39Robot societies among people31Agentic co-design of low-cost robots27Laundry-hanging robots25Machine learning on qualitative data23Robots on the building site27Civilizations & group psychology1History & human sciences1

Produced with AI assistance (Claude). Results are from the code in this repository and are simulated or stylised unless the abstract says otherwise; nothing here implies affiliation with or endorsement by any lab, researcher or company cited. MIT licensed.