Library/Fundamental Analysis and Valuation/Quality and Distress/Dechow-Dichev Accrual Quality

D18-F04-A12 / Complete engineering topic

Dechow-Dichev Accrual Quality

Estimate the original firm-specific regression, inspect every residual, and enforce the retrospective availability boundary created by future CFO.

Dechow-Dichev Accrual Quality maps point-in-time accounting inputs to an auditable quality or distress diagnosticD18 / D18-F04

Estimate the original firm-specific regression, inspect every residual, and enforce the retrospective availability boundary created by future CFO.

The decision this tutorial makes visible

Dechow-Dichev Accrual Quality matters because a compact score can organize a review queue, but only when its accounting definitions, original estimation population, availability clock, and interpretation boundary remain visible.

The precise question is: How much unexplained working-capital accrual variation remains after a firm-specific regression on past, current, and future operating cash flows?

A practitioner needs to know what the diagnostic does and does not justify. A builder needs a contract that can be reproduced from the same point-in-time inputs in Python, TypeScript, a visual, and a browser lab.

Intuition before notation

Accruals that map cleanly into adjacent-period cash flows have smaller residual dispersion; the future CFO term makes the result retrospective.

The result depends on the declared algorithm scope, input clocks, units, equality and rounding policies, and unsupported-state treatment. Change one of those and the output represents a different decision even when its field name is unchanged.

Scope and nearby methods

Dechow-Dichev 2002 firm-specific regression using scaled working-capital accruals and CFO at t-1, t, and t+1; accrual quality is residual standard deviation.

VariantDefinitionBest useMain limitation
Original DDFirm-specific past/current/future CFO regressionAccrual estimation qualityRetrospective and noisy
McNichols extensionAdds revenue change and PPEBroader explanatory modelNot this package
Cross-sectional DDIndustry-year estimationShort historiesDifferent error structure

What is sourced, selected, synthetic, and derived

RoleMaterial claimEvidenceBoundary
Sourced factDefines accrual quality as residual dispersion from mapping working-capital accruals to past, current, and future operating cash flows.S1 original or explicitly limited reproductionFuture cash flow makes the measure retrospective; window length, scaling, and later McNichols variants are separate choices.
Implementation choiceDechow-Dichev 2002 firm-specific regression using scaled working-capital accruals and CFO at t-1, t, and t+1; accrual quality is residual standard deviation.Frozen definition contract, code, fixtures, and parity testsNearby coefficient sets and variants remain separate.
Synthetic teaching inputAll company records, periods, peer samples, scenarios, and outputs are repository-authored synthetic data.datasets/canonical-input.json and scenario-results.jsonNo value is an observed issuer or provider record.
Author-derived calculationThe ten-period synthetic series creates eight centered rows, four OLS coefficients, eight fitted accruals and residuals, and a degrees-of-freedom residual standard deviation.Formula, expected-output.json, independent checks, and Python/TypeScript parityArithmetic fidelity does not validate prediction or company conclusions.
Scope boundaryThe output does not establish a current issuer conclusion, audit finding, rating, default forecast, investment return, or causal claim.No empirical current-population or advisory claim is testedUse as a documented screen or research measure only.

The authoritative sources support only the exact facts named in the claim ledger. They do not certify the synthetic numbers in this tutorial. The repository fixture is deliberately invented for auditability, and the displayed output is author-derived under the selected implementation choice.

Formula, symbols, and numerical policy

Plain text
WCA_t = β0 + β1 CFO_t-1 + β2 CFO_t + β3 CFO_t+1 + ε_t; AQ = sqrt(sum(ε²)/(n-k))
SymbolMeaningUnitPolicy
WCAWorking-capital accruals / average assetsratioAligned period
CFOOperating cash flow / average assetsratioPast/current/future
εOLS residualscaled accrualNot managerial discretion by definition
AQResidual standard deviationratioHigher = lower quality
  • Use full floating-point precision and round only for display.
  • Ratios are dimensionless unless a days or currency-scale contract is explicit.
  • Reject missing, nonfinite, boolean-as-number, zero-denominator, invalid-log, singular-regression, mixed-period, or unsupported records.
  • Keep the raw index, transformation, contribution vector, threshold policy, and diagnostic state together.

Read the formula in the same order as the algorithm. Validate identity, ordering, units, and supported state first. Apply the selected equality, cutoff, and estimation rules second. Calculate with unrounded numeric values. Round only at the declared presentation boundary, and preserve null as a diagnostic rather than coercing it to zero.

Build the algorithm

  1. Validate at least seven unique ordered periods.
  2. Create centered estimation rows with past/current/future CFO.
  3. Solve OLS and retain coefficients, fitted values, and residuals.
  4. Calculate degrees-of-freedom residual standard deviation.

Production-minded operational checklist

  1. Confirm model variant and original population
  2. Map every accounting input and clock
  3. Reconcile score contributions
  4. Treat the output as a review screen, not a conclusion

Stop when a required line item, filing clock, unit scale, original-population condition, or estimation sample is unavailable; do not manufacture precision from a familiar score name.

Worked synthetic example

The canonical fixture is synthetic teaching data, not an observed issuer, filing, audit case, or market outcome. Its primary author-derived output, accrual_quality, is four coefficients, eight fitted values and residuals, retrospective availability, and accrual-quality dispersion. The complete input and output are in datasets/canonical-input.json and datasets/expected-output.json.

The ten-period synthetic series creates eight centered rows, four OLS coefficients, eight fitted accruals and residuals, and a degrees-of-freedom residual standard deviation.

Counterfactual checkpoint

One-driver stress. Move one declared accounting driver while holding the remaining synthetic record fixed. The output changes because The score is a weighted mapping of the frozen inputs, not an independent fact.

The structured result retains state and diagnostics in addition to the primary number. That makes the calculation independently reviewable and prevents an incomplete, rejected, unsupported, or retrospective result from being mistaken for an unqualified conclusion.

Boundary and counterexample workbook

The playground computes every scenario at 61 deterministic parameter states. The table uses the declared focus step and states whether that focus reproduces the canonical fixture. The full state ledger and compressed transition segments are in datasets/scenario-results.json.

ScenarioReview focusPurposeStatePrimary outputDiagnosticDecision segments
Centered Y2 accrual windowStep 30 · canonical fixtureDriver: Y2 WCA with Y1/Y2/Y3 CFO. Sweep Y2 working-capital accrual while its centered CFO window stays visible. Predict: Will the Y2 residual move one-for-one with observed WCA?calculated+0.3109%calculated · higher residual dispersion means lower accrual quality · dechow-dichev-2002-firm-specific1
Centered Y3 CFOStep 30 · canonical fixtureDriver: Y3 CFO with Y2/Y3/Y4 CFO. Sweep the current CFO in the Y3 centered row. Predict: Will changing the current CFO alter fitted accrual and residual together?calculated+0.3109%calculated · higher residual dispersion means lower accrual quality · dechow-dichev-2002-firm-specific1
Centered Y4 accrual windowStep 30 · canonical fixtureDriver: Y4 WCA with Y3/Y4/Y5 CFO. Sweep Y4 working-capital accrual in a later centered row. Predict: Which residual dominates AQ when one WCA observation moves?calculated+0.3109%calculated · higher residual dispersion means lower accrual quality · dechow-dichev-2002-firm-specific1
Centered Y5 CFOStep 30 · canonical fixtureDriver: Y5 CFO with Y4/Y5/Y6 CFO. Sweep the current CFO in the Y5 centered row. Predict: Will a future-CFO window change the fitted relation?calculated+0.3109%calculated · higher residual dispersion means lower accrual quality · dechow-dichev-2002-firm-specific1
Centered Y6 accrual windowStep 30 · canonical fixtureDriver: Y6 WCA with Y5/Y6/Y7 CFO. Sweep Y6 working-capital accrual while retaining all other rows. Predict: Will one outlying accrual widen residual dispersion?calculated+0.3109%calculated · higher residual dispersion means lower accrual quality · dechow-dichev-2002-firm-specific1
Centered Y7 CFOStep 30 · canonical fixtureDriver: Y7 CFO with Y6/Y7/Y8 CFO. Sweep the current CFO in the Y7 centered row. Predict: Will the coefficient fit absorb or leave a residual?calculated+0.3109%calculated · higher residual dispersion means lower accrual quality · dechow-dichev-2002-firm-specific1
Centered Y8 accrual windowStep 30 · canonical fixtureDriver: Y8 WCA with Y7/Y8/Y9 CFO. Sweep Y8 working-capital accrual near the end of the sample. Predict: Why is the last usable row still unavailable until Y9 CFO is filed?calculated+0.3109%calculated · higher residual dispersion means lower accrual quality · dechow-dichev-2002-firm-specific1

These rows are not backtest observations. They are controlled counterexamples that expose how one driver changes the state, output, or reason code while the rest of the contract stays fixed.

Visualize the boundary

Dechow-Dichev Accrual Quality annotated teaching map

Open this SVG at full size, or use the guided playground to compare the seven topic-specific canonical, boundary, policy, and failure scenarios.

The Mermaid flow answers where the selected calculation sits in the processing sequence. The SVG keeps the formula, output, decision boundary, and invariant visible together. The lab lets the reader step through the same structured states without changing the underlying definition.

Implementation walkthrough

The Python and TypeScript references begin with the same validation contract, reject malformed and unsupported state before calculation, preserve declared ordering and rounding policies, and return structured diagnostics rather than one context-free number.

The main implementation branches are:

  • fewer than seven periods — Reject, because Insufficient residual degrees of freedom.
  • singular design — Reject, because Coefficients are not identifiable.
  • future CFO not yet filed — Mark unavailable, because Prevent hindsight.

Neither reference silently fetches data, mutates caller-owned inputs outside the declared engine behavior, guesses hidden state, or substitutes a provider default. Shared JSON fixtures make value, null, state, and reason-code drift visible across languages.

Testing and validation

Definition tests compare every canonical field, reject malformed state, and exercise the material boundary. Family validation recomputes every playground state from the reference function. Independent arithmetic is recorded beside the fixture rather than inferred only from implementation output.

The audit must preserve these invariants:

  • Each fitted accrual plus residual equals the observed accrual.
  • AQ uses n-k degrees of freedom with k=4.
  • The output is unavailable until the final t+1 CFO is known.
  • The output retains named predictors/components, raw score, screen or residual interpretation, and method identifier.

Passing checks proves the selected equation, mapping, scenario, and language parity. It does not validate out-of-sample classification performance.

Failure modes and misuse

  • The model can be stale, population-specific, industry-sensitive, and affected by accounting classification or business-model changes.
  • A threshold crossing is a screen for further review, not bankruptcy, fraud, audit, rating, or valuation evidence by itself.
  • Implementation fidelity does not prove predictive accuracy, causality, market usefulness, or suitability for a current jurisdiction.

Debugging order

When a result looks surprising, inspect the state in this order:

  1. Confirm the exact model variant and coefficients.
  2. Confirm filing availability and accounting mapping.
  3. Confirm units, scale, signs, periods, logs, and denominators.
  4. Reconcile each contribution or regression residual before interpreting the aggregate.

Evidence and historical boundary

Historical decision: not useful. A named issuer is not useful for the canonical arithmetic because a defensible case would require the exact filing version available at the decision date, a line-item mapping ledger, restatement and corporate-action treatment, model-population eligibility, coefficient provenance, and independently reproducible arithmetic. Original research samples establish model history; synthetic records isolate mechanics without alleging distress or misstatement by a real company.

The primary sources are Dechow and Dichev (2002), SEC financial-statement guide, IFRS Conceptual Framework. They support the source roles listed in the research ledger, not a redistributable historical observation, a current issuer conclusion, audit finding, rating, default forecast, investment return, or causal claim

Summary and next topic

You can now calculate, audit, and bound Dechow-Dichev Accrual Quality before continuing to Modified Jones Discretionary Accrual Model. The learning flow is: Dechow F-Score for Misstatement Risk → Dechow-Dichev Accrual Quality → Modified Jones Discretionary Accrual Model. Carry the result forward only with its scope, clock, state, and evidence label.

Deep visual atlas

Accounting model anatomy

Threshold and interpretation ceiling

Point-in-time evidence clock

Variant and misuse boundaries

Use the anatomy to reconstruct the score, the threshold map to preserve equality and interpretation, the clock to prevent hindsight, and the boundary map to stop variant drift.

Use the accounting studio

  1. Read the prediction prompt and name the direction before moving the state slider.
  2. Check the driver under test and compare the scenario base with the current state.
  3. Reconcile the visible intermediate (rolling past/current/future CFO window, fitted accrual, residual, and dispersion) to the headline.
  4. Apply the boundary and evidence clock: the minimum sample and future-CFO availability gates.
VisualQuestion it answersStudio handoff
Model anatomyWhat is the calculation order?Start with Qualify → Map → Calculate → Reconcile.
Threshold and interpretationWhat does equality mean?Move to the boundary scenario and read the interpretation ceiling.
Evidence clockWhat was knowable at the decision time?For A12, wait for future CFO; for A13, freeze the peer sample.
Variant boundariesWhich nearby model is not interchangeable?Compare the active driver with the claim ledger before changing the model.

Dechow-Dichev Accrual Quality calculation flow

This flow identifies the selected calculation stages and the structured output.

Rendering system map…

Takeaway: The most important feature is the clock: quality for period t cannot be known under this model until CFO at t+1 is available.

ReferencesPrimary sources and evidence notes

Expand the source trail, evidence role, and limitations behind the engineering choices.

S1 — The Quality of Accruals and Earnings: The Role of Accrual Estimation Errors

  • Organization or authors: Patricia M. Dechow and Ilia D. Dichev
  • Source type: Original peer-reviewed paper
  • Publication or effective date: 2002
  • Version: Original publication or cited edition
  • URL or DOI: https://doi.org/10.2308/accr.2002.77.s-1.35
  • Accessed: 2026-08-06
  • Jurisdiction: U.S. firm-year research sample
  • Supports: Defines accrual quality as residual dispersion from mapping working-capital accruals to past, current, and future operating cash flows.
  • Limitations: Future cash flow makes the measure retrospective; window length, scaling, and later McNichols variants are separate choices.

S2 — Beginners' Guide to Financial Statements

  • Organization or authors: U.S. Securities and Exchange Commission
  • Source type: Official regulator publication
  • Publication or effective date: 2007-02-05
  • Version: Original publication or cited edition
  • URL or DOI: https://www.sec.gov/about/reports-publications/investor-publications/beginners-guide-financial-statements
  • Accessed: 2026-08-06
  • Jurisdiction: United States public-company reporting
  • Supports: Balance sheets describe a point in time, income and cash-flow statements describe a period, and the notes are integral to interpretation.
  • Limitations: It does not prescribe any score, line-item mapping, coefficient, cutoff, or empirical conclusion.

S3 — Conceptual Framework for Financial Reporting

Evidence boundary

The original research source establishes the named historical model and research context. It does not certify this synthetic fixture, a current population calibration, or a company conclusion. SEC/IFRS sources establish statement context only.

quality-distress.ts
/** Canonical TypeScript reference for D18-F04 Quality and Distress. */

type RecordValue = Record<string, unknown>;

function objectValue(data: RecordValue, name: string): RecordValue {
  const value = data[name];
  if (!value || typeof value !== "object" || Array.isArray(value)) throw new TypeError(`${name} must be an object`);
  return value as RecordValue;
}

function numberValue(data: RecordValue, name: string): number {
  const value = data[name];
  if (typeof value !== "number" || !Number.isFinite(value)) throw new TypeError(`${name} must be a finite number`);
  return value;
}

function positive(data: RecordValue, name: string): number {
  const value = numberValue(data, name);
  if (value <= 0) throw new RangeError(`${name} must be positive`);
  return value;
}

function nonnegative(data: RecordValue, name: string): number {
  const value = numberValue(data, name);
  if (value < 0) throw new RangeError(`${name} must be nonnegative`);
  return value;
}

function booleanValue(data: RecordValue, name: string): boolean {
  const value = data[name];
  if (typeof value !== "boolean") throw new TypeError(`${name} must be a boolean`);
  return value;
}

function ratio(numerator: number, denominator: number, name: string): number {
  if (denominator === 0) throw new RangeError(`${name} denominator must be nonzero`);
  return numerator / denominator;
}

function logistic(index: number): number {
  if (index >= 0) { const z = Math.exp(-index); return 1 / (1 + z); }
  const z = Math.exp(index); return z / (1 + z);
}

function normalCdf(value: number): number {
  const sign = value < 0 ? -1 : 1;
  const x = Math.abs(value) / Math.sqrt(2);
  const t = 1 / (1 + 0.3275911 * x);
  const polynomial = (((((1.061405429 * t - 1.453152027) * t) + 1.421413741) * t - 0.284496736) * t + 0.254829592) * t;
  const erfValue = sign * (1 - polynomial * Math.exp(-x * x));
  return 0.5 * (1 + erfValue);
}

function sum(values: Record<string, number>): number { return Object.values(values).reduce((a, b) => a + b, 0); }

function altman(data: RecordValue): RecordValue {
  const assets = positive(data, "total_assets"), liabilities = positive(data, "total_liabilities");
  const ratios = {
    working_capital_to_assets: numberValue(data, "working_capital") / assets,
    retained_earnings_to_assets: numberValue(data, "retained_earnings") / assets,
    ebit_to_assets: numberValue(data, "ebit") / assets,
    market_equity_to_liabilities: nonnegative(data, "market_value_equity") / liabilities,
    sales_to_assets: numberValue(data, "sales") / assets,
  };
  const contributions = {
    working_capital: 1.2 * ratios.working_capital_to_assets,
    retained_earnings: 1.4 * ratios.retained_earnings_to_assets,
    ebit: 3.3 * ratios.ebit_to_assets,
    market_equity: 0.6 * ratios.market_equity_to_liabilities,
    sales: ratios.sales_to_assets,
  };
  const score = sum(contributions);
  const zone = score < 1.81 ? "distress-zone" : score > 2.99 ? "safe-zone" : "grey-zone";
  return {state:"calculated",method:"altman-1968-public-manufacturer",ratios,contributions,z_score:score,zone,threshold_policy:"distress<1.81; grey=1.81..2.99; safe>2.99"};
}

function piotroski(data: RecordValue): RecordValue {
  const beginAssets=positive(data,"beginning_total_assets"), priorBeginAssets=positive(data,"prior_beginning_total_assets");
  const currentAssets=positive(data,"current_assets"), currentLiabilities=positive(data,"current_liabilities");
  const priorCurrentAssets=positive(data,"prior_current_assets"), priorCurrentLiabilities=positive(data,"prior_current_liabilities");
  const sales=positive(data,"sales"), priorSales=positive(data,"prior_sales");
  const netIncome=numberValue(data,"net_income"), priorNetIncome=numberValue(data,"prior_net_income"), cfo=numberValue(data,"operating_cash_flow");
  const roa=netIncome/beginAssets, priorRoa=priorNetIncome/priorBeginAssets;
  const signals = {
    positive_roa: +(roa>0), positive_cfo: +(cfo>0), improving_roa: +(roa>priorRoa), cash_exceeds_income: +(cfo>netIncome),
    lower_leverage: +(numberValue(data,"long_term_debt")/beginAssets < numberValue(data,"prior_long_term_debt")/priorBeginAssets),
    higher_current_ratio: +(currentAssets/currentLiabilities > priorCurrentAssets/priorCurrentLiabilities),
    no_equity_issue: +(nonnegative(data,"equity_issued")===0),
    higher_gross_margin: +(numberValue(data,"gross_profit")/sales > numberValue(data,"prior_gross_profit")/priorSales),
    higher_asset_turnover: +(sales/beginAssets > priorSales/priorBeginAssets),
  };
  const score=sum(signals), band=score<=2?"weak-signals":score>=8?"strong-signals":"mixed-signals";
  return {state:"calculated",method:"piotroski-2000-nine-signal",signals,f_score:score,band,signal_count:9};
}

function beneish(data: RecordValue): RecordValue {
  const sales=positive(data,"sales"), priorSales=positive(data,"prior_sales");
  const receivables=nonnegative(data,"receivables"), priorReceivables=nonnegative(data,"prior_receivables");
  const grossMargin=(sales-numberValue(data,"cost_of_goods_sold"))/sales;
  const priorGrossMargin=(priorSales-numberValue(data,"prior_cost_of_goods_sold"))/priorSales;
  if (grossMargin===0 || priorGrossMargin===0) throw new RangeError("gross margins must be nonzero");
  const assets=positive(data,"total_assets"), priorAssets=positive(data,"prior_total_assets");
  const currentAssetQuality=1-(numberValue(data,"current_assets")+numberValue(data,"net_ppe")+numberValue(data,"securities"))/assets;
  const priorAssetQuality=1-(numberValue(data,"prior_current_assets")+numberValue(data,"prior_net_ppe")+numberValue(data,"prior_securities"))/priorAssets;
  if (priorAssetQuality===0) throw new RangeError("prior asset-quality denominator must be nonzero");
  const depreciationRate=ratio(numberValue(data,"depreciation"),numberValue(data,"net_ppe")+numberValue(data,"depreciation"),"depreciation rate");
  const priorDepreciationRate=ratio(numberValue(data,"prior_depreciation"),numberValue(data,"prior_net_ppe")+numberValue(data,"prior_depreciation"),"prior depreciation rate");
  const indices={
    dsri:ratio(receivables/sales,priorReceivables/priorSales,"DSRI"), gmi:priorGrossMargin/grossMargin,
    aqi:currentAssetQuality/priorAssetQuality, sgi:sales/priorSales, depi:priorDepreciationRate/depreciationRate,
    sgai:ratio(numberValue(data,"sga_expense")/sales,numberValue(data,"prior_sga_expense")/priorSales,"SGAI"),
    lvgi:ratio((numberValue(data,"current_liabilities")+numberValue(data,"long_term_debt"))/assets,(numberValue(data,"prior_current_liabilities")+numberValue(data,"prior_long_term_debt"))/priorAssets,"LVGI"),
    tata:(numberValue(data,"income_from_continuing_operations")-numberValue(data,"operating_cash_flow"))/assets,
  };
  const contributions={intercept:-4.84,dsri:.92*indices.dsri,gmi:.528*indices.gmi,aqi:.404*indices.aqi,sgi:.892*indices.sgi,depi:.115*indices.depi,sgai:-.172*indices.sgai,tata:4.679*indices.tata,lvgi:-.327*indices.lvgi};
  const score=sum(contributions);
  return {state:"calculated",method:"beneish-1999-eight-variable",indices,contributions,m_score:score,screen:score>-1.78?"above-screening-cutoff":"below-screening-cutoff",cutoff:-1.78};
}

function sloan(data: RecordValue): RecordValue {
  const avgAssets=positive(data,"average_total_assets");
  const deltaCa=numberValue(data,"current_assets")-numberValue(data,"prior_current_assets");
  const deltaCash=numberValue(data,"cash")-numberValue(data,"prior_cash");
  const deltaCl=numberValue(data,"current_liabilities")-numberValue(data,"prior_current_liabilities");
  const deltaStd=numberValue(data,"short_term_debt")-numberValue(data,"prior_short_term_debt");
  const deltaTax=numberValue(data,"taxes_payable")-numberValue(data,"prior_taxes_payable");
  const depreciation=nonnegative(data,"depreciation_and_amortization");
  const accrualAmount=(deltaCa-deltaCash)-(deltaCl-deltaStd-deltaTax)-depreciation, measure=accrualAmount/avgAssets;
  return {state:"calculated",method:"sloan-1996-balance-sheet-accrual",delta_current_assets:deltaCa,delta_cash:deltaCash,delta_current_liabilities:deltaCl,delta_short_term_debt:deltaStd,delta_taxes_payable:deltaTax,depreciation_and_amortization:depreciation,accrual_amount:accrualAmount,accrual_measure:measure,absolute_accrual_measure:Math.abs(measure),interpretation:measure<0?"income-decreasing-accrual":measure>0?"income-increasing-accrual":"zero-net-accrual"};
}

function ohlson(data: RecordValue): RecordValue {
  const assets=positive(data,"total_assets"), priceIndex=positive(data,"price_level_index"), liabilities=positive(data,"total_liabilities");
  const currentAssets=positive(data,"current_assets"), currentLiabilities=nonnegative(data,"current_liabilities");
  const netIncome=numberValue(data,"net_income"), priorIncome=numberValue(data,"prior_net_income"), chinDenominator=Math.abs(netIncome)+Math.abs(priorIncome);
  if (chinDenominator===0) throw new RangeError("current and prior net income cannot both be zero");
  const variables={size:Math.log(assets/priceIndex),tlta:liabilities/assets,wcta:numberValue(data,"working_capital")/assets,clca:currentLiabilities/currentAssets,oeneg:+(liabilities>assets),nita:netIncome/assets,futl:numberValue(data,"funds_from_operations")/liabilities,intwo:+(netIncome<0&&priorIncome<0),chin:(netIncome-priorIncome)/chinDenominator};
  const score=-1.32-.407*variables.size+6.03*variables.tlta-1.43*variables.wcta+.0757*variables.clca-1.72*variables.oeneg-2.37*variables.nita-1.83*variables.futl+.285*variables.intwo-.521*variables.chin;
  const probability=logistic(score);
  return {state:"calculated",method:"ohlson-1980-model-1",variables,o_score:score,logistic_probability:probability,screen:probability>.038?"above-original-cutoff":"below-original-cutoff",cutoff_probability:.038};
}

function zmijewski(data: RecordValue): RecordValue {
  const assets=positive(data,"total_assets"), liabilities=nonnegative(data,"total_liabilities"), currentLiabilities=positive(data,"current_liabilities");
  const variables={roa:numberValue(data,"net_income")/assets,leverage:liabilities/assets,current_ratio:numberValue(data,"current_assets")/currentLiabilities};
  const score=-4.336-4.513*variables.roa+5.679*variables.leverage+.004*variables.current_ratio, probability=normalCdf(score);
  return {state:"calculated",method:"zmijewski-1984-probit",variables,x_score:score,probit_probability:probability,screen:score>0?"distress-side":"non-distress-side",index_cutoff:0};
}

function springate(data: RecordValue): RecordValue {
  const assets=positive(data,"total_assets"), currentLiabilities=positive(data,"current_liabilities");
  const ratios={working_capital_to_assets:numberValue(data,"working_capital")/assets,ebit_to_assets:numberValue(data,"ebit")/assets,ebt_to_current_liabilities:numberValue(data,"ebt")/currentLiabilities,sales_to_assets:numberValue(data,"sales")/assets};
  const score=1.03*ratios.working_capital_to_assets+3.07*ratios.ebit_to_assets+.66*ratios.ebt_to_current_liabilities+.4*ratios.sales_to_assets;
  return {state:"calculated",method:"springate-1978-four-ratio",ratios,s_score:score,screen:score<.862?"distress-side":"non-distress-side",cutoff:.862};
}

function taffler(data: RecordValue): RecordValue {
  const currentLiabilities=positive(data,"current_liabilities"), liabilities=positive(data,"total_liabilities"), assets=positive(data,"total_assets"), dailyExpenses=positive(data,"daily_operating_expenses");
  const ratios={pbt_to_current_liabilities:numberValue(data,"profit_before_tax")/currentLiabilities,current_assets_to_total_liabilities:numberValue(data,"current_assets")/liabilities,current_liabilities_to_total_assets:currentLiabilities/assets,no_credit_interval_days:(numberValue(data,"quick_assets")-currentLiabilities)/dailyExpenses};
  const score=3.2+12.18*ratios.pbt_to_current_liabilities+2.5*ratios.current_assets_to_total_liabilities-10.68*ratios.current_liabilities_to_total_assets+.0289*ratios.no_credit_interval_days;
  return {state:"calculated",method:"taffler-1983-uk-industrial-transformed",ratios,z_score:score,screen:score<0?"distress-side":"non-distress-side",index_cutoff:0};
}

function fulmer(data: RecordValue): RecordValue {
  const assets=positive(data,"total_assets"), debt=positive(data,"total_debt"), equity=positive(data,"equity"), interest=positive(data,"interest_expense"), tangible=positive(data,"tangible_assets_usd_thousands"), ebit=numberValue(data,"ebit");
  if (ebit/interest<=0) throw new RangeError("EBIT/interest must be positive for the logarithm");
  const variables={retained_earnings_to_assets:numberValue(data,"retained_earnings")/assets,sales_to_assets:numberValue(data,"sales")/assets,ebt_to_equity:numberValue(data,"ebt")/equity,operating_cash_flow_to_debt:numberValue(data,"operating_cash_flow")/debt,debt_to_assets:debt/assets,current_liabilities_to_assets:numberValue(data,"current_liabilities")/assets,log10_tangible_assets_usd_thousands:Math.log10(tangible),working_capital_to_debt:numberValue(data,"working_capital")/debt,log10_ebit_interest:Math.log10(ebit/interest)};
  const score=5.528*variables.retained_earnings_to_assets+.212*variables.sales_to_assets+.073*variables.ebt_to_equity+1.270*variables.operating_cash_flow_to_debt-.120*variables.debt_to_assets+2.335*variables.current_liabilities_to_assets+.575*variables.log10_tangible_assets_usd_thousands+1.083*variables.working_capital_to_debt+.894*variables.log10_ebit_interest-6.075;
  return {state:"calculated",method:"fulmer-1984-small-firm-nine-factor",variables,h_score:score,screen:score<0?"distress-side":"non-distress-side",index_cutoff:0,scale_policy:"tangible assets expressed in USD thousands before log10"};
}

function grover(data: RecordValue): RecordValue {
  const assets=positive(data,"total_assets");
  const variables={working_capital_to_assets:numberValue(data,"working_capital")/assets,ebit_to_assets:numberValue(data,"ebit")/assets,roa:numberValue(data,"net_income")/assets};
  const score=1.650*variables.working_capital_to_assets+3.404*variables.ebit_to_assets-.016*variables.roa+.057;
  const zone=score<=-.02?"distress-zone":score>=.01?"non-distress-zone":"grey-zone";
  return {state:"calculated",method:"grover-2001-reported-reestimation",variables,g_score:score,zone,threshold_policy:"distress<=-0.02; grey=(-0.02,0.01); non-distress>=0.01"};
}

function noa(row: RecordValue): number {
  return numberValue(row,"total_assets")-numberValue(row,"cash")-numberValue(row,"investments_and_advances")+numberValue(row,"investments_at_equity")-numberValue(row,"total_liabilities")-numberValue(row,"preferred_stock");
}

function dechowF(data: RecordValue): RecordValue {
  const current=objectValue(data,"current"), prior=objectValue(data,"prior"), prior2=objectValue(data,"prior2");
  const avgAssets=(positive(current,"total_assets")+positive(prior,"total_assets"))/2;
  const priorAvgAssets=(positive(prior,"total_assets")+positive(prior2,"total_assets"))/2;
  const currentCashSales=numberValue(current,"sales")-(numberValue(current,"receivables")-numberValue(prior,"receivables"));
  const priorCashSales=numberValue(prior,"sales")-(numberValue(prior,"receivables")-numberValue(prior2,"receivables"));
  if (priorCashSales===0) throw new RangeError("prior cash sales must be nonzero");
  const variables={
    rsst_accruals:(noa(current)-noa(prior))/avgAssets,
    change_receivables:(numberValue(current,"receivables")-numberValue(prior,"receivables"))/avgAssets,
    change_inventory:(numberValue(current,"inventory")-numberValue(prior,"inventory"))/avgAssets,
    soft_assets:(numberValue(current,"total_assets")-numberValue(current,"net_ppe")-numberValue(current,"cash"))/numberValue(current,"total_assets"),
    change_cash_sales:currentCashSales/priorCashSales-1,
    change_roa:numberValue(current,"net_income")/avgAssets-numberValue(prior,"net_income")/priorAvgAssets,
    actual_issuance:+booleanValue(data,"issued_equity_or_long_term_debt"),
  };
  const logit=-7.893+.790*variables.rsst_accruals+2.518*variables.change_receivables+1.191*variables.change_inventory+1.979*variables.soft_assets+.171*variables.change_cash_sales-.932*variables.change_roa+1.029*variables.actual_issuance;
  const probability=logistic(logit), score=probability/.0037;
  const band=score<=1?"at-or-below-baseline":score<1.85?"above-baseline":score<2.45?"substantial":"high-screen";
  return {state:"calculated",method:"dechow-et-al-2011-model-1",variables,logit,misstatement_probability:probability,f_score:score,band,unconditional_probability:.0037};
}

function solve(matrix: number[][], vector: number[]): number[] {
  const n=vector.length, augmented=matrix.map((row,index)=>[...row,vector[index]]);
  for(let col=0;col<n;col++){
    let pivot=col;
    for(let row=col+1;row<n;row++) if(Math.abs(augmented[row][col])>Math.abs(augmented[pivot][col])) pivot=row;
    if(Math.abs(augmented[pivot][col])<1e-12) throw new RangeError("regression design matrix is singular");
    [augmented[col],augmented[pivot]]=[augmented[pivot],augmented[col]];
    const scale=augmented[col][col]; augmented[col]=augmented[col].map(value=>value/scale);
    for(let row=0;row<n;row++) if(row!==col){
      const factor=augmented[row][col];
      augmented[row]=augmented[row].map((left,index)=>left-factor*augmented[col][index]);
    }
  }
  return augmented.map(row=>row[row.length-1]);
}

function ols(x: number[][], y: number[]): [number[],number[]] {
  if(!x.length||x.length!==y.length) throw new RangeError("regression requires aligned observations");
  const width=x[0].length;
  if(x.length<=width||x.some(row=>row.length!==width)) throw new RangeError("regression requires more aligned observations than predictors");
  const xtx=Array.from({length:width},(_,i)=>Array.from({length:width},(_,j)=>x.reduce((total,row)=>total+row[i]*row[j],0)));
  const xty=Array.from({length:width},(_,i)=>x.reduce((total,row,index)=>total+row[i]*y[index],0));
  const beta=solve(xtx,xty);
  const residuals=y.map((target,index)=>target-beta.reduce((total,coefficient,j)=>total+coefficient*x[index][j],0));
  return [beta,residuals];
}

function dechowDichev(data: RecordValue): RecordValue {
  const raw=data.observations;
  if(!Array.isArray(raw)||raw.length<7||raw.some(row=>!row||typeof row!=="object"||Array.isArray(row))) throw new RangeError("observations must contain at least seven period records");
  const rows=raw as RecordValue[], cfo=rows.map(row=>numberValue(row,"cfo_scaled")), accruals=rows.map(row=>numberValue(row,"working_capital_accrual_scaled")), periods=rows.map(row=>String(row.period??""));
  if(periods.some(period=>!period)||new Set(periods).size!==periods.length) throw new RangeError("period labels must be unique and nonempty");
  const x=rows.slice(1,-1).map((_,offset)=>{const index=offset+1;return [1,cfo[index-1],cfo[index],cfo[index+1]];});
  const y=accruals.slice(1,-1), [beta,residuals]=ols(x,y), df=residuals.length-beta.length;
  const residualStd=Math.sqrt(residuals.reduce((total,value)=>total+value*value,0)/df), fitted=y.map((target,index)=>target-residuals[index]);
  return {state:"calculated",method:"dechow-dichev-2002-firm-specific",coefficients:{intercept:beta[0],cfo_t_minus_1:beta[1],cfo_t:beta[2],cfo_t_plus_1:beta[3]},estimation_periods:periods.slice(1,-1),fitted_accruals:fitted,residuals,accrual_quality:residualStd,interpretation:"higher residual dispersion means lower accrual quality",available_after_period:periods[periods.length-1]};
}

function modifiedJones(data: RecordValue): RecordValue {
  const raw=data.industry_year_sample, targetId=data.target_id;
  if(!Array.isArray(raw)||raw.length<5||raw.some(row=>!row||typeof row!=="object"||Array.isArray(row))) throw new RangeError("industry_year_sample must contain at least five records");
  if(typeof targetId!=="string"||!targetId) throw new TypeError("target_id must be a nonempty string");
  const rows=raw as RecordValue[], ids=rows.map(row=>row.entity_id);
  if(new Set(ids).size!==ids.length||!ids.includes(targetId)) throw new RangeError("entity IDs must be unique and include target_id");
  const design=(row:RecordValue):number[]=>{const priorAssets=positive(row,"prior_total_assets");return [1/priorAssets,(numberValue(row,"revenue_change")-numberValue(row,"receivables_change"))/priorAssets,numberValue(row,"net_ppe")/priorAssets];};
  const peers=rows.filter(row=>row.entity_id!==targetId), x=peers.map(design), y=peers.map(row=>numberValue(row,"total_accruals")/positive(row,"prior_total_assets"));
  const [beta,residuals]=ols(x,y), target=rows.find(row=>row.entity_id===targetId) as RecordValue, targetX=design(target);
  const scaledTotal=numberValue(target,"total_accruals")/positive(target,"prior_total_assets"), nondiscretionary=beta.reduce((total,coefficient,index)=>total+coefficient*targetX[index],0), discretionary=scaledTotal-nondiscretionary;
  return {state:"calculated",method:"modified-jones-1995-peer-estimation",target_id:targetId,estimation_count:peers.length,coefficients:{inverse_assets:beta[0],revenue_less_receivables:beta[1],net_ppe:beta[2]},peer_residuals:residuals,scaled_total_accruals:scaledTotal,nondiscretionary_accruals:nondiscretionary,discretionary_accruals:discretionary,absolute_discretionary_accruals:Math.abs(discretionary),interpretation:"signed residual; no universal manipulation cutoff"};
}

const calculators: Record<string,(data:RecordValue)=>RecordValue> = {
  "D18-F04-A01":altman,"D18-F04-A02":piotroski,"D18-F04-A03":beneish,"D18-F04-A04":sloan,
  "D18-F04-A05":ohlson,"D18-F04-A06":zmijewski,"D18-F04-A07":springate,"D18-F04-A08":taffler,
  "D18-F04-A09":fulmer,"D18-F04-A10":grover,"D18-F04-A11":dechowF,"D18-F04-A12":dechowDichev,"D18-F04-A13":modifiedJones,
};

export function calculate(topicId: string, data: RecordValue): RecordValue {
  if(!data||typeof data!=="object"||Array.isArray(data)) throw new TypeError("data must be an object");
  const calculator=calculators[topicId];
  if(!calculator) throw new RangeError(`unsupported topic_id: ${topicId}`);
  return calculator(data);
}
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