{"source":"NYS ORPTS SalesWeb arm's-length single-family (class 210) sales, City of Elmira 2018–2025, joined to the 2025 assessment roll. Sale prices restated in 2025 dollars.","method":{"target":"E[market value | assessed value]","rule":"Sort on assessed value, then average the PRICE. Never average the ratio. A ratio is assessed/price, so sorting on either variable tilts it; the conditional mean of the price is an ordinary regression and is not tilted.","form":"piecewise-linear least squares in log-log, linear beyond the outer knots","notAFairnessCurve":"Conditioning on assessed value shrinks predictions toward the middle of the roll, because a high assessment is partly a high true value and partly assessment error. That is correct for prediction and wrong as a measure of fairness — for fairness see jcurve.html. It also means a real revaluation would spread outcomes wider than modelled here.","baseYear":2025,"rollYear":2025,"newLoa":0.85,"sales":1668,"minBandSales":30},"model":{"knots":[30000,40000,50000,65000,90000,150000],"coefficients":[7.416466,0.309821,1.635342,-0.023341,-1.013512,0.21141,-0.401054,0.060106],"smearing":1.088334,"validFrom":20000,"validTo":200000,"sparseBelow":30000,"sparseAbove":120000,"evaluate":"log-log piecewise linear: let x = ln(assessed); mv = exp(c0 + c1*x + sum_i c_{i+2} * max(x - ln(knot_i), 0)) * smearing"},"uncertainty":{"residualSd":0.435,"saleNoiseSd":0.232,"repeatSalePairs":510,"valueSd":0.368,"interval":0.8,"note":"A prediction interval on one home's value, not on the average. The residual spread is split using the repeat-sales estimate of how far an individual sale price strays from market value; what is left is the uncertainty that belongs to the house."},"curve":[{"assessed":20000,"market":38926,"ci":[34870,43965],"ratio":0.514},{"assessed":30000,"market":44137,"ci":[39950,48427],"ratio":0.68},{"assessed":40000,"market":77237,"ci":[72822,81596],"ratio":0.518},{"assessed":50000,"market":118596,"ci":[113642,123547],"ratio":0.422},{"assessed":65000,"market":150510,"ci":[141486,158598],"ratio":0.432},{"assessed":90000,"market":216678,"ci":[195363,236293],"ratio":0.415},{"assessed":150000,"market":312788,"ci":[291894,335358],"ratio":0.48},{"assessed":200000,"market":391335,"ci":[367907,409936],"ratio":0.511}],"rates":{"currentBilledRate":65.19,"currentBilledRateSource":"The four lines every city parcel carries on a 2025 tax bill (city, county, community college, school), per $1,000 of assessed value.","newBilledRate":35.64,"newLoa":0.85,"parcels":5834,"currentTaxableBase":292149416,"estimatedMarketTotal":628631272,"newTaxableBase":534336581,"levyModelled":19045220,"note":"Both rates come from the same levy over the same group of parcels, so the pair is revenue-neutral by construction. The rate falls by nearly half because the base nearly doubles — the same dollars, collected against values that are no longer thirty years stale."},"impliedResidentialRatio":0.4647,"bands":[{"label":"Under $30K","parcels":684,"salesBacking":151,"thin":false,"sparse":false,"medianAssessed":26000,"medianMarket":42223,"medianCurrentBill":1695,"medianNewBill":1279,"medianChange":-416,"shareDown":0.925},{"label":"$30–40K","parcels":1142,"salesBacking":304,"thin":false,"sparse":false,"medianAssessed":36000,"medianMarket":62924,"medianCurrentBill":2347,"medianNewBill":1906,"medianChange":-440,"shareDown":1.0},{"label":"$40–50K","parcels":1811,"salesBacking":500,"thin":false,"sparse":false,"medianAssessed":45000,"medianMarket":96857,"medianCurrentBill":2934,"medianNewBill":2934,"medianChange":1,"shareDown":0.359},{"label":"$50–60K","parcels":1252,"salesBacking":362,"thin":false,"sparse":false,"medianAssessed":55000,"medianMarket":129320,"medianCurrentBill":3585,"medianNewBill":3918,"medianChange":332,"shareDown":0.0},{"label":"$60–80K","parcels":673,"salesBacking":229,"thin":false,"sparse":false,"medianAssessed":66000,"medianMarket":153105,"medianCurrentBill":4303,"medianNewBill":4639,"medianChange":336,"shareDown":0.0},{"label":"$80–120K","parcels":155,"salesBacking":65,"thin":false,"sparse":false,"medianAssessed":90000,"medianMarket":216678,"medianCurrentBill":5867,"medianNewBill":6565,"medianChange":616,"shareDown":0.0},{"label":"$120K+","parcels":117,"salesBacking":57,"thin":false,"sparse":true,"medianAssessed":163000,"medianMarket":333703,"medianCurrentBill":10626,"medianNewBill":10110,"medianChange":-516,"shareDown":0.838}],"examples":[{"percentile":10,"assessed":30000,"market":44137,"marketLow":25304,"marketHigh":64997,"newAssessed":37516,"currentBill":1956,"newBill":1337,"change":-619,"parcelsAtOrBelow":684},{"percentile":25,"assessed":38000,"market":69903,"marketLow":40075,"marketHigh":102941,"newAssessed":59417,"currentBill":2477,"newBill":2118,"change":-359,"parcelsAtOrBelow":1478},{"percentile":50,"assessed":47000,"market":105299,"marketLow":60368,"marketHigh":155067,"newAssessed":89504,"currentBill":3064,"newBill":3190,"change":126,"parcelsAtOrBelow":3065},{"percentile":75,"assessed":56000,"market":131454,"marketLow":75363,"marketHigh":193583,"newAssessed":111736,"currentBill":3651,"newBill":3983,"change":332,"parcelsAtOrBelow":4466},{"percentile":90,"assessed":67000,"market":155705,"marketLow":89266,"marketHigh":229295,"newAssessed":132349,"currentBill":4368,"newBill":4717,"change":350,"parcelsAtOrBelow":5268},{"percentile":99,"assessed":162670,"market":333177,"marketLow":191011,"marketHigh":490646,"newAssessed":283200,"currentBill":10604,"newBill":10094,"change":-510,"parcelsAtOrBelow":5775}],"sensitivity":{"loa":{"low":0.4257,"high":0.466,"specifications":18},"newRate":{"low":32.6511,"high":35.7416,"specifications":18},"shareDown":{"low":0.4052,"high":0.4878,"specifications":18},"bandMedianChange":{"Under $30K":{"low":-423,"high":-299,"signStable":true},"$30–40K":{"low":-539,"high":-430,"signStable":true},"$40–50K":{"low":-48,"high":209,"signStable":false},"$50–60K":{"low":282,"high":435,"signStable":true},"$60–80K":{"low":307,"high":432,"signStable":true},"$80–120K":{"low":162,"high":669,"signStable":true},"$120K+":{"low":-938,"high":-247,"signStable":true}},"note":"Refit under every combination of three price indices, two sale windows and three knot sets. The level of assessment and the new rate barely move. The share of households paying less does, because Elmira's assessed values pile up exactly where this model's winners and losers divide — thousands of parcels change sides under a change that moves nothing else. That share is therefore published as a RANGE and never as a point estimate; under deliberately underfitted curves it reaches 74%. The withdrawn model published it as '69% of homes pay less', and a reader's refusal to believe that single figure is what exposed the error. The median change within a band is stable and is what the page reports."},"validation":{"stateRar":{"2015":0.8152,"2016":0.8225,"2017":0.8438,"2018":0.8058,"2019":0.8207,"2020":0.8236,"2021":0.8431,"2022":0.7,"2023":0.6185,"2024":0.61,"2025":0.5208},"stateEqRate":{"2015":0.83,"2016":0.83,"2017":0.83,"2018":0.81,"2019":0.83,"2020":0.83,"2021":0.85,"2022":0.7,"2023":0.66,"2024":0.61,"2025":0.56},"stateRarLatest":0.5208,"stateRarYear":2025,"modelImpliedRatio":0.4647,"observedMedianRatioByYear":{"2018":0.758,"2019":0.7686,"2020":0.7136,"2021":0.6327,"2022":0.576,"2023":0.5337,"2024":0.5062,"2025":0.467},"note":"The state's Residential Assessment Ratio is an independent measure of the same quantity, computed by ORPTS from its own sales study. It runs slightly above this model because it is a lagging series in a rising market. Both are far below the 78% of market the withdrawn model implied, and both sit below the all-property equalization rate — houses are assessed at a smaller fraction of their value than the roll average."},"stateEquityStats":[{"year":2004,"residentialRatio":93.51,"equalizationRate":99.5,"residentialCod":15.6,"residentialPrd":1.06,"allPropertyCod":14.51,"allPropertyPrd":1.03,"method":"Sales Ratio"},{"year":2005,"residentialRatio":91.39,"equalizationRate":98.0,"residentialCod":14.25,"residentialPrd":1.04,"allPropertyCod":13.16,"allPropertyPrd":1.01,"method":"Sales Ratio"},{"year":2006,"residentialRatio":93.3,"equalizationRate":98.0,"residentialCod":12.89,"residentialPrd":1.04,"allPropertyCod":12.09,"allPropertyPrd":1.01,"method":"Sales Ratio"},{"year":2007,"residentialRatio":86.16,"equalizationRate":94.0,"residentialCod":17.88,"residentialPrd":1.05,"allPropertyCod":18.12,"allPropertyPrd":1.02,"method":"Sales Ratio"},{"year":2008,"residentialRatio":84.72,"equalizationRate":92.0,"residentialCod":23.93,"residentialPrd":1.1,"allPropertyCod":23.67,"allPropertyPrd":1.06,"method":"Sales Ratio"},{"year":2009,"residentialRatio":81.9,"equalizationRate":90.0,"residentialCod":19.64,"residentialPrd":1.07,"allPropertyCod":19.86,"allPropertyPrd":1.03,"method":"Sales Ratio"},{"year":2010,"residentialRatio":84.02,"equalizationRate":90.0,"residentialCod":28.28,"residentialPrd":1.12,"allPropertyCod":27.37,"allPropertyPrd":1.07,"method":"Sales Ratio"},{"year":2011,"residentialRatio":86.64,"equalizationRate":90.0,"residentialCod":25.87,"residentialPrd":1.1,"allPropertyCod":24.05,"allPropertyPrd":1.09,"method":"Sales Ratio"},{"year":2012,"residentialRatio":90.36,"equalizationRate":90.0,"residentialCod":21.69,"residentialPrd":1.09,"allPropertyCod":20.72,"allPropertyPrd":1.1,"method":"Sales Ratio"},{"year":2013,"residentialRatio":85.65,"equalizationRate":89.0,"residentialCod":27.97,"residentialPrd":1.12,"allPropertyCod":25.65,"allPropertyPrd":1.11,"method":"Sales Ratio"},{"year":2014,"residentialRatio":78.65,"equalizationRate":84.0,"residentialCod":25.96,"residentialPrd":1.1,"allPropertyCod":24.49,"allPropertyPrd":1.08,"method":"Sales Ratio"},{"year":2015,"residentialRatio":81.52,"equalizationRate":83.0,"residentialCod":27.66,"residentialPrd":1.12,"allPropertyCod":25.77,"allPropertyPrd":1.11,"method":"Sales Ratio"},{"year":2016,"residentialRatio":82.25,"equalizationRate":83.0,"residentialCod":24.71,"residentialPrd":1.11,"allPropertyCod":23.35,"allPropertyPrd":1.1,"method":"Sales Ratio"},{"year":2017,"residentialRatio":84.38,"equalizationRate":83.0,"residentialCod":30.89,"residentialPrd":1.14,"allPropertyCod":29.25,"allPropertyPrd":1.14,"method":"Sales Ratio"},{"year":2018,"residentialRatio":80.58,"equalizationRate":81.0,"residentialCod":33.16,"residentialPrd":1.15,"allPropertyCod":30.54,"allPropertyPrd":1.14,"method":"Sales Ratio"},{"year":2019,"residentialRatio":82.07,"equalizationRate":83.0,"residentialCod":34.39,"residentialPrd":1.17,"allPropertyCod":33.61,"allPropertyPrd":1.13,"method":"Sales Ratio"},{"year":2020,"residentialRatio":82.36,"equalizationRate":83.0,"residentialCod":31.62,"residentialPrd":1.15,"allPropertyCod":31.58,"allPropertyPrd":1.11,"method":"Sales Ratio"},{"year":2021,"residentialRatio":84.31,"equalizationRate":85.0,"residentialCod":34.25,"residentialPrd":1.17,"allPropertyCod":33.45,"allPropertyPrd":1.14,"method":"Sales Ratio"},{"year":2022,"residentialRatio":70.0,"equalizationRate":70.0,"residentialCod":17.69,"residentialPrd":1.04,"allPropertyCod":18.96,"allPropertyPrd":1.02,"method":"CAMA"},{"year":2023,"residentialRatio":61.85,"equalizationRate":66.0,"residentialCod":32.93,"residentialPrd":1.14,"allPropertyCod":32.42,"allPropertyPrd":1.1,"method":"Sales Ratio"},{"year":2024,"residentialRatio":61.0,"equalizationRate":61.0,"residentialCod":46.19,"residentialPrd":1.26,"allPropertyCod":44.41,"allPropertyPrd":1.2,"method":"Sales Ratio"},{"year":2025,"residentialRatio":52.08,"equalizationRate":56.0,"residentialCod":39.39,"residentialPrd":1.2,"allPropertyCod":39.38,"allPropertyPrd":1.13,"method":"Sales Ratio"}],"sources":{"sales":"NYS ORPTS SalesWeb extract, arm's-length class-210 transfers.","roll":"NYS ORPTS assessment rolls, data.ny.gov 7vem-aaz7, City of Elmira (SWIS 070400), 2025 roll, taxable section only.","rar":"NYS Dept. of Taxation and Finance, data.ny.gov bsmp-6um6, Residential Assessment Ratios.","equity":"NYS Dept. of Taxation and Finance, data.ny.gov 4sut-q3dt, Real Property Assessment Equity Statistics By Municipality.","equalization":"NYS data.ny.gov e6pv-77bh, Equalization Rates."},"generated":"2026-08-05"}