Estimation.ATT
AIPW/DML estimation of the average treatment effect on the treated (Hahn-form moment), mirroring the ATE development; the top-level theorem files are pending repair against the current Mathlib pin.
Setup 9 core · 7 supporting Defines the treated-estimation system for ATT estimation under back-door assumptions. ★ θ₀_eq_ATT
Defines the treated-estimation system for ATT estimation under back-door assumptions. The structure bundles value-space representatives for the control outcome regression, propensity score, treatment probability, and compatibility fields needed by ATT AIPW moments.
The file introduces TreatedEstimationSystem, derives the control-arm
counterfactual compatibility lemma μ₀_compat, defines the one-sided overlap
predicate OneSidedOverlap, the covariate and data laws P_X and P_Z, the
value-space target θ₀, and proves θ₀_eq_ATT. It also constructs a
TreatedEstimationSystem from a POBackdoorSystem with overlap and an
integrable observed outcome via POBackdoorSystem.toTreatedEstimationSystem.
A treated estimation system extends a potential-outcome back-door system with a measurable control-arm outcome regression, a measurable propensity score, a pointwise upper propensity bound, almost-everywhere agreement with the observable control regression, and almost-everywhere agreement with the observable propensity.
Definition (Lean source)
For a potential-outcome system with a measurable covariate space, a treated estimation system, and a real margin, the one-sided overlap condition holds exactly when and the conditional probability of treatment given the covariates is at most almost surely under the population measure.
Definition (Lean source)
For a potential-outcome system with a measurable covariate space and a treated estimation system, the covariate distribution is the image of the population measure under the factual covariate.
Definition (Lean source)
For a potential-outcome system with a measurable covariate space and a treated estimation system, the factual data-recording map sends every population unit to its observed covariate, observed treatment, and observed outcome.
Definition (Lean source)
For a potential-outcome system with a measurable covariate space and a treated estimation system, the joint observable-data distribution is the image of the population measure under the factual map recording covariate, treatment, and outcome.
Definition (Lean source)
For a potential-outcome system with a measurable covariate space and a treated estimation system, the marginal treatment probability is the population probability that the factual treatment equals one.
Definition (Lean source)
For a potential-outcome system with a measurable covariate space and a treated estimation system, the value-space average treatment effect on the treated is the system's adjusted control-regression functional.
Definition (Lean source)
Value-space estimand equals the potential-outcome ATT. Under the one-sided back-door ATT assumptions, the value-space ATT estimand θ₀ (the adjusted control-regression functional) coincides with the average treatment effect on the treated defined on potential outcomes.
Formal statement
Proof (Lean source)
Given a potential-outcome system with a measurable covariate space, a potential-outcome back-door system, the condition that its conditional probability of treatment lies strictly between zero and one almost surely, and an integrable factual outcome, the constructed treated estimation system extends that back-door system with a control-arm outcome regression and a propensity-score representative bounded strictly below one.
Definition (Lean source)
7 supporting declarations (lemmas, instances)
-
conditionalMeanOutcome_backdoor_controllemma — For a treated-outcome estimation system under the one-sided ATT assumptions, the control-arm conditional mean equals its adjusted control outcome. No treated-arm overlap is used.hypothesesγ :sharedType u_1S :hA :S.toPOBackdoorSystem.ATTAssumptionsProof (Lean source)
lemma conditionalMeanOutcome_backdoor_control (S : TreatedEstimationSystem P γ) (hA : S.toPOBackdoorSystem.ATTAssumptions) : S.toPOBackdoorSystem.conditionalMeanOutcome false =ᵐ[P.μ] S.toPOBackdoorSystem.adjustedCE false := S.toPOBackdoorSystem.conditionalMeanOutcome_backdoor_of_propScore_ne hA.consistency false hA.unconfoundedness hA.integrable_Y1 hA.integrable_Y0 hA.propScore_false_ne -
propScore_true_nonneg_aelemma — Treated propensity nonnegativity. The conditional treatment probability P[D=1 | X] is nonnegative almost surely because it is the conditional expectation of a nonnegative treatment indicator.hypothesesconclusion∀ᵐ ω ∂P.μ, 0 ≤ S.toPOBackdoorSystem.propScore true ωProof (Lean source)
lemma propScore_true_nonneg_ae (S : TreatedEstimationSystem P γ) : ∀ᵐ ω ∂P.μ, 0 ≤ S.toPOBackdoorSystem.propScore true ω := MeasureTheory.condExp_nonneg (Filter.Eventually.of_forall (fun ω => by rcases S.toPOBackdoorSystem.dVar.indicator_eq_one_or_zero true ω with h | h <;> simp [h])) -
μ₀_compatlemma — Counterfactual compatibility (derived, under ATT identification). The control-arm outcome-regression representative equals the conditional mean of the untreated potential outcome given the covariates, almost surely.hypothesesγ :sharedType u_1S :hA :S.toPOBackdoorSystem.ATTAssumptionsconclusionP.μ[S.toPOBackdoorSystem.YofD false | S.toPOBackdoorSystem.sigmaX]=ᵐ[P.μ] (fun ω => S.μ₀_val (S.toPOBackdoorSystem.factualX ω))Proof (Lean source)
lemma μ₀_compat (S : TreatedEstimationSystem P γ) (hA : S.toPOBackdoorSystem.ATTAssumptions) : P.μ[S.toPOBackdoorSystem.YofD false | S.toPOBackdoorSystem.sigmaX] =ᵐ[P.μ] (fun ω => S.μ₀_val (S.toPOBackdoorSystem.factualX ω)) := (S.conditionalMeanOutcome_backdoor_control hA).trans S.μ₀_reg_compat.symm -
P_X_eqlemma — The covariate marginal is the image of the population measure under the factual covariate map.hypothesesconclusionS.P_X = P.μ.map S.toPOBackdoorSystem.factualXProof (Lean source)
@[causal_defs_simps] lemma P_X_eq (S : TreatedEstimationSystem P γ) : S.P_X = P.μ.map S.toPOBackdoorSystem.factualX := rfl -
measurable_factualZlemma — Measurability of the data triple.hypothesesconclusionMeasurable S.factualZProof (Lean source)
@[fun_prop] lemma measurable_factualZ (S : TreatedEstimationSystem P γ) : Measurable S.factualZ := (S.toPOBackdoorSystem.measurable_factualX).prodMk ((S.toPOBackdoorSystem.measurable_factualD).prodMk S.toPOBackdoorSystem.measurable_factualY) -
P_Z_eqlemma — The joint data law is the image of the population measure under the map recording the observed covariate, treatment, and outcome.hypothesesconclusionS.P_Z = P.μ.map S.factualZProof (Lean source)
@[causal_defs_simps] lemma P_Z_eq (S : TreatedEstimationSystem P γ) : S.P_Z = P.μ.map S.factualZ := rfl -
P_Z_map_projX_eq_P_Xlemma — The covariate marginal P_X is the pushforward of P_Z along the projection (x, a, y) ↦ x. Used to bridge integrals/eLpNorm between P_X (covariates only) and P_Z (full data triple).hypothesesconclusionS.P_Z.map (fun z : γ × Bool × ℝ => z.1) = S.P_XProof (Lean source)
lemma P_Z_map_projX_eq_P_X (S : TreatedEstimationSystem P γ) : S.P_Z.map (fun z : γ × Bool × ℝ => z.1) = S.P_X := by unfold TreatedEstimationSystem.P_Z TreatedEstimationSystem.P_X rw [Measure.map_map (by fun_prop : Measurable (fun z : γ × Bool × ℝ => z.1)) S.measurable_factualZ] rfl
ATTInstance 2 core · 2 supporting Instantiates the abstract orthogonal-moment DML theorem for the average treatment effect on the treated. ★ att_oneStepOracleDML_isAsymLinear
Instantiates the abstract orthogonal-moment DML theorem for the average treatment effect on the treated. It connects the ATT AIPW score, remainder identity, score-continuity bounds, and sample-splitting assumptions to asymptotic linearity.
The main declarations are attGeneralMoment, the MeanZero bridge
att_meanZero, the bilinear remainder bridge att_bilinearRem, and the
headline abstract asymptotic-linearity theorem att_oneStepOracleDML_isAsymLinear. This
file is the ATT specialization of the general orthogonal-moment interface; the
user-facing estimator wrapper is in Estimation/ATT/DML.lean.
For a potential-outcomes system with a standard Borel sample space and finite probability measure, a measurable covariate space, a treated estimation system, a real overlap radius, the condition that the system's true nuisance vector belongs to its overlap-bounded candidate set at that radius, and the condition that its marginal treatment probability is strictly positive, the ATT augmented inverse-probability-weighted general moment is the general moment whose score is the ATT AIPW score, whose target nuisance vector and target parameter are the system's true nuisance vector and ATT, whose candidate set is that overlap-bounded set, whose two seminorms are the distances between control-outcome regressions and between propensity scores, and whose Jacobian is the negative marginal treatment probability.
Definition (Lean source)
Asymptotic linearity of the oracle one-step DML estimator of the average treatment effect on the treated (ATT). Fix a sequence of nuisance fits η̂_n, each a control-regression fit paired with a propensity fit, an i.i.d. sample of the covariate–treatment–outcome triple, and a one-shot split of that sample into a training fold and an evaluation fold. Under membership of the true nuisance in the overlap-bounded nuisance class, nonnegativity of the true propensity score, one-sided overlap with margin ε for the true propensity score, the one-sided back-door assumptions for the ATT, a strictly positive marginal treatment probability, square-integrability of the observed outcome and of the untreated potential outcome Y(0), integrability of the control-arm inverse-probability-weighting correction at the truth, and a positive limit c to which the evaluation-fold share of the sample converges: if every fit η̂_n lies in the overlap-bounded nuisance class, every fitted propensity is nonnegative, the control-regression and propensity errors of every fit are square-integrable under the covariate law, the inverse-probability-weighting correction at every fit is integrable under the observed-data law, the ATT score at the fitted nuisance and the true ATT is measurable jointly in the realization and the observation, and measurable with respect to the product of the σ-algebra generated by the training-fold observations and the observation σ-algebra, that score is integrable and square-integrable under the observed-data law at every fit, the two nuisance error gauges, which measure the L² errors of the fits under the covariate law, are each o_p(1), and their product is o_p(n^(−1/2)), then the oracle one-step estimator, the true ATT plus the evaluation-fold average of the ATT score at the fitted nuisance divided by the marginal treatment probability, is asymptotically linear at the true ATT along the evaluation fold, with influence function equal to the ATT augmented inverse-probability-weighted score at the true nuisance divided by the marginal treatment probability.
Formal statement
Proof (Lean source)
2 supporting declarations (lemmas, instances)
-
att_meanZerotheorem — ATT AIPW mean-zero packaging. Given membership of the true nuisance in the candidate set, the one-sided ATT assumptions, positive marginal treatment probability, and integrability of the inverse-probability-weighted control residual, the ATT AIPW general moment has mean zero. This is a direct repackaging of aipw_mean_zero_ATT from Estimation/ATT/Score/MeanZero.lean.hypothesesγ :sharedType u_1S :ε :ℝhη₀_mem :S.η₀ ∈ H_ε S εhA :S.toPOBackdoorSystem.ATTAssumptionshπ_pos :0 < S.π_valhIPW :Integrable (fun ω => (1 - S.toPOBackdoorSystem.dVar.indicator true ω) * (S.toPOBackdoorSystem.propScore true ω / (1 - S.toPOBackdoorSystem.propScore true ω)) * (S.toPOBackdoorSystem.factualY ω - S.toPOBackdoorSystem.adjustedCE false ω)) P.μconclusionMeanZero (attGeneralMoment S hη₀_mem hπ_pos)Proof (Lean source)
theorem att_meanZero (S : TreatedEstimationSystem P γ) {ε : ℝ} (hη₀_mem : S.η₀ ∈ H_ε S ε) (hA : S.toPOBackdoorSystem.ATTAssumptions) (hπ_pos : 0 < S.π_val) (hIPW : Integrable (fun ω => (1 - S.toPOBackdoorSystem.dVar.indicator true ω) * (S.toPOBackdoorSystem.propScore true ω / (1 - S.toPOBackdoorSystem.propScore true ω)) * (S.toPOBackdoorSystem.factualY ω - S.toPOBackdoorSystem.adjustedCE false ω)) P.μ) : MeanZero (attGeneralMoment S hη₀_mem hπ_pos) := by unfold MeanZero attGeneralMoment exact aipw_mean_zero_ATT S hA hπ_pos hIPW -
att_bilinearRemtheorem — ATT AIPW satisfies BilinearRemainder with constant aipw_rem_const_ATT ε.hypothesesγ :sharedType u_1S :ε :ℝhη₀_mem :S.η₀ ∈ H_ε S εh_overlap :S.OneSidedOverlap εhA :S.toPOBackdoorSystem.ATTAssumptionshπ_pos :0 < S.π_valh_y2 :Integrable (fun ω => (S.toPOBackdoorSystem.factualY ω) ^ 2) P.μh_y0_2 :Integrable (fun ω => (S.toPOBackdoorSystem.YofD false ω) ^ 2) P.μh_L2 :conclusion∃ C, BilinearRemainder (attGeneralMoment S hη₀_mem hπ_pos) CProof (Lean source)
theorem att_bilinearRem (S : TreatedEstimationSystem P γ) {ε : ℝ} (hη₀_mem : S.η₀ ∈ H_ε S ε) (h_overlap : S.OneSidedOverlap ε) (hA : S.toPOBackdoorSystem.ATTAssumptions) (hπ_pos : 0 < S.π_val) (h_y2 : Integrable (fun ω => (S.toPOBackdoorSystem.factualY ω) ^ 2) P.μ) (h_y0_2 : Integrable (fun ω => (S.toPOBackdoorSystem.YofD false ω) ^ 2) P.μ) (h_L2 : ∀ η ∈ H_ε S ε, MemLp (fun x => η.μ₀_fn x - S.μ₀_val x) 2 S.P_X ∧ MemLp (fun x => η.e_fn x - S.e_val x) 2 S.P_X) (h_IPW : ∀ η ∈ H_ε S ε, Integrable (fun z => (1 - indA z) * (η.e_fn (projX z) / (1 - η.e_fn (projX z))) * (projY z - η.μ₀_fn (projX z))) S.P_Z) : ∃ C, BilinearRemainder (attGeneralMoment S hη₀_mem hπ_pos) C := by refine ⟨aipw_rem_const_ATT ε, ?_⟩ intro η hη obtain ⟨hΔμ₀, hΔe⟩ := h_L2 η hη have h := aipw_remainder_bound_ATT S h_overlap hA hπ_pos h_y2 h_y0_2 η hη hΔμ₀ hΔe (h_IPW η hη) change |∫ z, aipwMomentATTFunctional η z S.θ₀ ∂(S.P_Z)| ≤ aipw_rem_const_ATT ε * (eLpNorm (fun x => η.μ₀_fn x - S.μ₀_val x) 2 S.P_X).toReal * (eLpNorm (fun x => η.e_fn x - S.e_val x) 2 S.P_X).toReal exact h