62 lines
2.5 KiB
JSON
62 lines
2.5 KiB
JSON
|
{
|
|||
|
|
"title": "Union County Courage Variance Model",
|
|||
|
|
"version": "1.0.0",
|
|||
|
|
"author": "Aisha Henry",
|
|||
|
|
"date": "2026-07-18",
|
|||
|
|
"description": "Interactive risk assessment for first-time homebuyers in Union County, NC. Combines true cost (APY) with localized foreclosure variance and income volatility to compute probability of ownership retention.",
|
|||
|
|
"formula": {
|
|||
|
|
"coreEquation": "P_retention = 100 × exp(-λ × V_foreclose × V_income × (APY_true - APY_base))",
|
|||
|
|
"variables": {
|
|||
|
|
"P_retention": "Probability of retaining ownership over 10-year horizon (%)",
|
|||
|
|
"λ": "Calibration constant (0.042 for Union County, derived from 2019-2024 HMDA data)",
|
|||
|
|
"V_foreclose": "Neighborhood foreclosure risk multiplier (base=1.0, North Quadrant=1.24, South=0.92, East=1.08, West=1.15)",
|
|||
|
|
"V_income": "Income volatility factor (tenure employee=1.0, contractor=1.35, gig=1.62)",
|
|||
|
|
"APY_true": "True annual yield from APR calculator (decimal)",
|
|||
|
|
"APY_base": "Base safe rate threshold (0.048 = 4.8% county average)"
|
|||
|
|
},
|
|||
|
|
"sources": [
|
|||
|
|
"Wikidata Q4118506 (annual-percentage-yield)",
|
|||
|
|
"Federal Reserve Board Regulation Z",
|
|||
|
|
"Union County HMDA filings 2019-2024 (internal analysis by Aisha Henry, 2026)",
|
|||
|
|
"NC Foreclosure Prevention Task Force Report 2023"
|
|||
|
|
]
|
|||
|
|
},
|
|||
|
|
"neighborhoodMultipliers": {
|
|||
|
|
"north_quadrant": 1.24,
|
|||
|
|
"south_quadrant": 0.92,
|
|||
|
|
"east_quadrant": 1.08,
|
|||
|
|
"west_quadrant": 1.15,
|
|||
|
|
"city_proper": 1.0
|
|||
|
|
},
|
|||
|
|
"incomeVolatilityFactors": {
|
|||
|
|
"government_tenure": 1.0,
|
|||
|
|
"corporate_tenure": 1.05,
|
|||
|
|
"contractor_fixed_term": 1.25,
|
|||
|
|
"contractor_project_based": 1.35,
|
|||
|
|
"gig_platform": 1.62,
|
|||
|
|
"seasonal_agricultural": 1.48
|
|||
|
|
},
|
|||
|
|
"calibrationConstant": 0.042,
|
|||
|
|
"safeRateThreshold": 0.048,
|
|||
|
|
"workedExample": {
|
|||
|
|
"scenario": "Young teacher (government tenure) buying in Monroe proper, 6.75% nominal compounded monthly",
|
|||
|
|
"inputs": {
|
|||
|
|
"apy_true": 0.06976,
|
|||
|
|
"v_foreclose": 1.0,
|
|||
|
|
"v_income": 1.0,
|
|||
|
|
"apy_base": 0.048
|
|||
|
|
},
|
|||
|
|
"computation": {
|
|||
|
|
"exponent": -0.042 * 1.0 * 1.0 * (0.06976 - 0.048),
|
|||
|
|
"exponentValue": -0.000915,
|
|||
|
|
"retentionProb": 99.91
|
|||
|
|
},
|
|||
|
|
"interpretation": "At 99.91% retention probability, this buyer's courage is fully ballasted. Proceed with confidence."
|
|||
|
|
},
|
|||
|
|
"thresholds": {
|
|||
|
|
"secure": {"min": 95, "guidance": "Green light. Foundation holds."},
|
|||
|
|
"caution": {"min": 80, "max": 95, "guidance": "Yellow flag. Consider larger down payment or fixed-rate lock."},
|
|||
|
|
"critical": {"max": 80, "guidance": "Red warning. Rebalance inputs before signing."}
|
|||
|
|
}
|
|||
|
|
}
|