Assumptions and verification
Claim revision: catalog:bb8b86d8685cad9cd917f8aa5c8738674fe3cbbfd195a15063beadeb2a3ce53e
Standing assumptions: The work is a three-page letter (Statistics and Probability Letters 83 (2013) 677–679) with one proposition and one corollary, each with a short printed proof, and one application. Everything below was read from the rendered page images (the staged pages, and the staged PDF re-rendered at 260 dpi when this list was fixed). [Setting: Section 2, first paragraph, p. 678 (PDF p. 2)] “We follow the setup of Angrist and Pischke (2009, Chapter 4). Let $Y_i(d, z)$ be the potential outcome of unit $i$ under treatment $d \in \{0, 1\}$ and assignment $z \in \{0, 1\}$, let $D_i(z)$ be the potential treatment of unit $i$ under assignment $z$, and let $Z_i$ be the treatment assigned to unit $i$. The causal effect for unit $i$ is then $Y_i(1, Z_i) - Y_i(0, Z_i)$. We assume (i) random assignment: $[Y_i(d, z), D_i(z) : d, z \in \{0, 1\}] \perp\!\!\!\perp Z_i$; (ii) exclusion restriction: $Y_i(d, z)$ does not depend on $z$, so we may write $Y_i(d, z) = Y_i(d)$; (iii) non-zero first-stage effect: $E[D_i(1) - D_i(0)] \ne 0$; (iv) monotonicity: $\forall i$, $D_i(1) \ge D_i(0)$. We make two notational simplifications. First, given (i), labels are exchangeable and so we drop notational dependence on $i$. Second, we define $P_c \equiv \Pr[D(1) > D(0)]$, $EY_1 \equiv \mathrm{E}[Y|Z = 1]$, and $EY_0 \equiv \mathrm{E}[Y|Z = 0]$.” [LATE display and bounded outcomes: Section 2, second paragraph, p. 678 (PDF p. 2)] “This setting implies that the ``LATE theorem'' (Angrist and Pischke, 2009, Theorem 4.4.1) holds: the CACE, $\mathrm{E}[Y(1) - Y(0)|D(1) > D(0)]$, is equal to $$\frac{\mathrm{E}[Y|Z = 1] - \mathrm{E}[Y|Z = 0]}{\mathrm{E}[D|Z = 1] - \mathrm{E}[D|Z = 0]} = \frac{EY_1 - EY_0}{P_c},$$ where each component may be estimated using sample analogues to population quantities. The associated estimator is logically equivalent to the Wald instrumental variables estimator (Angrist et al., 1996). We make one additional assumption to ensure partial identification: we require that outcomes are bounded. Without loss of generality, fix $Y \in [0, 1]$.” [Typography] The page prints the expectation operator upright in most places ($\mathrm{E}[Y|Z = 1]$) and in italics in assumption (iii) ($E[D_i(1) - D_i(0)]$); it is one operator. $EY_1$, $EY_0$, $EY_n$, $EY_c(0)$, $EY_c(1)$ and $P_c$ are names of real numbers, not products. [What the paper does not print] The paper does not define the observed treatment $D$ and the observed outcome $Y$ that appear in $\mathrm{E}[Y|Z = z]$, $\mathrm{E}[D|Z = z]$, $\mathrm{E}[Y|D = d, Z = z]$ and $\Pr[D = d|Z = z]$ (the relations $D = D(Z)$ and $Y = Y(D(Z))$ are not displayed). It does not say that both assignment arms have positive probability. It does not assume $P_c < 1$: (iii) and (iv) give $0 < P_c \le 1$ only, and ‘two-sided noncompliance’ is stated in Section 4 for the application alone. It does not say whether ‘$Y \in [0, 1]$’ bounds the observed outcome or both potential outcomes. It does not define ‘known’, ‘sharp’, ‘identified’ or ‘point identified’. It has no response or missing-data indicator and no assumption about outcomes that are not recorded. [Remarks for the formalizer, not printed in the paper] The reading the audit's validators settled on is: one probability space (a generic unit) carrying $Z \in \{0,1\}$ with $0 < \Pr[Z = 1] < 1$, potential treatments $D(0), D(1) \in \{0,1\}$ and potential outcomes $Y(0), Y(1) \in [0,1]$ (exclusion is built in: $Y(d,z) = Y(d)$), with $(Y(0), Y(1), D(0), D(1))$ independent of $Z$, $D(1) \ge D(0)$, $\mathrm{E}[D(1) - D(0)] \ne 0$, and observed $D = D(Z)$, $Y = Y(D(Z))$. The unit index is suppressed as generic-unit population notation; the validator of finding P028-N002 (rated a clarity note) established that the printed reason for dropping it (‘given (i), labels are exchangeable’) does not follow from (i) and is not needed, and that no identical-distribution or random-sampling assumption has to be added. Principal strata: compliers $C = \{D(1) > D(0)\} = \{D(0) = 0, D(1) = 1\}$, always-takers $A = \{D(0) = D(1) = 1\}$, never-takers $N = \{D(0) = D(1) = 0\}$; monotonicity excludes $\{D(0) = 1, D(1) = 0\}$, so $D(1) - D(0) = \mathbf{1}_C$, $P_c = \Pr(C) = \mathrm{E}[D(1) - D(0)] = \mathrm{E}[D|Z = 1] - \mathrm{E}[D|Z = 0]$ and $0 < P_c \le 1$; $\Pr(A) = \Pr[D = 1|Z = 0]$, $\Pr(N) = \Pr[D = 0|Z = 1]$ and $\Pr(A) + \Pr(N) = 1 - P_c$. A conditional mean given an event is the elementary one and is defined only when the event has positive probability. Lean's division is total ($x/0 = 0$), so a statement that a printed quotient or conditional mean is undefined has to be stated as the failure of a side condition (a zero denominator, a null conditioning event), not as a property of the quotient's value. Boundedness is used only in Proposition 1; the LATE display and Corollary 1 need integrable outcomes only. [Why the list has ten targets] Three findings rated as errors concern a mathematical statement or rest on an exact formal counterexample. P028-N005 (Moderate): the application presents point estimates of the complier means although 71 of 1000 outcomes are missing and no response assumption is stated; the validator confirmed this with two exact laws that agree on everything observed and disagree on the complier means, so the counterexample (T1), the formal content of the corrected claim (T2) and the passage as printed (T3) are targets. P028-E001 (Minor): a misprinted upper limit and a wrong symbol in the proof of Proposition 1; corrected statement (T4) and the validator's counterexample to the printed intermediate system (T5). P028-E002 (Minor): the proof of Proposition 1 does not cover $P_c = 1$; corrected statement (T6) and the validator's counterexample to the unqualified proof step (T7). The fourth error, P028-E003 (Minor), is a volume number in the reference list and has no mathematical statement to correct. P028-N002 and P028-N007 are clarity notes; P028-N003, P028-N004 and P028-N006 were not confirmed; P028-N001 is undetermined. Of the seven headline claims, H1 (Proposition 1, T8), H3 (Corollary 1, T9) and H2 (the LATE identity and the statement that the three figures do not identify the complier means, T10) are mathematical statements. H4 (the count of 6 of 20 studies), H5 and H6 (the application's estimates) and H7 (the reporting recommendation) are an empirical count, empirical estimates and a recommendation, and are not targets; the formal content behind H6 is reached through P028-N005.
Effective claim (source TeX): Sol's repair (validated.json, P028-N005, smallest_repair), verbatim: "State the target population, outcome/viewing coding and analysis denominators, and qualify the application by a sufficient response assumption for the moments actually estimated. For the mixed available-case approach, mean equality between respondents and the full population is needed for both assignment-arm outcome means and the two noncomplier-cell outcome means; response independent of (Y,D) within each assignment arm is one sufficient stronger condition. If assuming only mean-ignorable response within (D,Z) cells, reweight the observed cell means by full-sample cell probabilities before applying Corollary 1 and recompute. Without an added response assumption, replace the point-identification inference with missing-outcome sensitivity bounds."
Mathematical content, with every hypothesis (validator's derivation.md, sections ‘Exact completions and the Corollary 1 identity’ and ‘Repair and dependency’). Setting: one probability space (a generic unit) carrying $Z \in \{0,1\}$ with $0 < \Pr[Z = 1] < 1$, potential treatments $D(0), D(1) \in \{0,1\}$ and potential outcomes $Y(0), Y(1) \in [0,1]$ (exclusion is built in: $Y(d,z) = Y(d)$), with $(Y(0), Y(1), D(0), D(1))$ independent of $Z$, $D(1) \ge D(0)$, $\mathrm{E}[D(1) - D(0)] \ne 0$, and observed $D = D(Z)$, $Y = Y(D(Z))$; in addition a response indicator $R \in \{0,1\}$ on the same space (the outcome is recorded when $R = 1$; $Z$ and $D$ are recorded for every unit). Write $C = \{D(1) > D(0)\}$, $P_c = \Pr(C) = \mathrm{E}[D|Z = 1] - \mathrm{E}[D|Z = 0] > 0$, $c_d = \mathrm{E}[Y(d)|C]$, $q = \Pr[D = 1|Z = 0]$, $r = \Pr[D = 0|Z = 1]$, so that $P_c = 1 - q - r$.
(i) [Corollary 1 in joint-moment form; no condition on $R$ and no positivity of cells.] $$P_c\, c_0 = \mathrm{E}[Y(1 - D)|Z = 0] - \mathrm{E}[Y(1 - D)|Z = 1], \qquad P_c\, c_1 = \mathrm{E}[Y D|Z = 1] - \mathrm{E}[Y D|Z = 0].$$
(ii) [Mixed available-case version: take-up from all units, outcome means from respondents.] Suppose $q > 0$, $r > 0$, $\Pr[R = 1|Z = z] > 0$ for $z = 0, 1$, $\Pr[R = 1|D = 1, Z = 0] > 0$, $\Pr[R = 1|D = 0, Z = 1] > 0$, and (M1) $\mathrm{E}[Y|Z = z, R = 1] = \mathrm{E}[Y|Z = z]$ for $z = 0, 1$; (M2) $\mathrm{E}[Y|D = 1, Z = 0, R = 1] = \mathrm{E}[Y|D = 1, Z = 0]$ and $\mathrm{E}[Y|D = 0, Z = 1, R = 1] = \mathrm{E}[Y|D = 0, Z = 1]$. Then $$c_0 = \frac{\mathrm{E}[Y|Z = 0, R = 1] - q\,\mathrm{E}[Y|D = 1, Z = 0, R = 1] - r\,\mathrm{E}[Y|D = 0, Z = 1, R = 1]}{P_c}, \qquad c_1 = c_0 + \frac{\mathrm{E}[Y|Z = 1, R = 1] - \mathrm{E}[Y|Z = 0, R = 1]}{P_c}.$$
(iii) [A sufficient stronger condition.] If, for each $z \in \{0,1\}$, $R$ is independent of $(Y, D)$ conditionally on $Z = z$ and $\Pr[R = 1|Z = z] > 0$, then (M1) holds, (M2) holds whenever $q > 0$ and $r > 0$, and the response probabilities required in (ii) are positive; so the conclusion of (ii) holds.
(iv) [Mean-ignorable response within $(D, Z)$ cells.] Suppose that for every $(d, z)$ with $\Pr[D = d|Z = z] > 0$, $\Pr[R = 1|D = d, Z = z] > 0$ and $\mathrm{E}[Y|D = d, Z = z, R = 1] = \mathrm{E}[Y|D = d, Z = z]$. Then, with the term of an empty cell omitted in each expression, $EY_z = \sum_{d} \Pr[D = d|Z = z]\,\mathrm{E}[Y|D = d, Z = z, R = 1]$ for $z = 0, 1$ and $$c_0 = \frac{\Pr[D = 0|Z = 0]\,\mathrm{E}[Y|D = 0, Z = 0, R = 1] - r\,\mathrm{E}[Y|D = 0, Z = 1, R = 1]}{P_c}, \qquad c_1 = \frac{\Pr[D = 1|Z = 1]\,\mathrm{E}[Y|D = 1, Z = 1, R = 1] - q\,\mathrm{E}[Y|D = 1, Z = 0, R = 1]}{P_c}.$$ Under this hypothesis alone the unweighted respondent arm means $\mathrm{E}[Y|Z = z, R = 1]$ need not equal $EY_z$, so the formula of (ii) is not justified by it.
(v) [No response condition: sensitivity bounds.] With no condition on $R$, $$\frac{\mathrm{E}[R Y (1 - D)|Z = 0] - \mathrm{E}[R Y (1 - D)|Z = 1] - \Pr[R = 0, D = 0|Z = 1]}{P_c} \ \le\ c_0\ \le\ \frac{\mathrm{E}[R Y (1 - D)|Z = 0] + \Pr[R = 0, D = 0|Z = 0] - \mathrm{E}[R Y (1 - D)|Z = 1]}{P_c},$$ $$\frac{\mathrm{E}[R Y D|Z = 1] - \mathrm{E}[R Y D|Z = 0] - \Pr[R = 0, D = 1|Z = 0]}{P_c} \ \le\ c_1\ \le\ \frac{\mathrm{E}[R Y D|Z = 1] + \Pr[R = 0, D = 1|Z = 1] - \mathrm{E}[R Y D|Z = 0]}{P_c},$$ and every quantity on the outer sides is a function of the law of the observed data $(Z, D, R, R \cdot Y)$.
Worked instance (the source table of P028-T1, read as a population law; validator's output.txt). (ii) gives $\left(\tfrac{1594452863}{3629163146}, \tfrac{896530960}{1244058109}\right) \approx (0.4393, 0.7207)$; (iv) gives $\left(\tfrac{16568969}{38014837}, \tfrac{295510}{414829}\right) \approx (0.4359, 0.7124)$; (v) gives $c_0 \in \left[\tfrac{1423}{10235}, \tfrac{7633}{10235}\right] \approx [0.1390, 0.7458]$ and $c_1 \in \left[\tfrac{6749}{10235}, \tfrac{7642}{10235}\right] \approx [0.6594, 0.7467]$, and each of the four endpoints is attained by a witness of P028-T1, so for this observed law the bounds of (v) cannot be narrowed without a response condition.
: SAP.P028.T2WholeStatement
Theorem: SAP.P028.T2
Statement hash: 5b42146f5bccd19b85c8dc4a4ee87d51f9493c0c91cf9ee6f99d9b58841da2d5
Statement definition: SAP.P028.T2WholeStatement
Certificate. 20261104T182914Z
Declaration review: faithful; 2026-11-04T18:49:53Z; binding v2
Evidence scope: Certification checks formal proof objects. Statement fidelity is a model judgment. Author review is separate.
Proof dependencies: Independently extracted
Manifest annotation reconciliation: Effective use follows the source-bound dependency observation; original annotations are retained in the crosswalk.
AronowAudit.P028.arm_event_cell_indicator: observed used
AronowAudit.P028.arm_event_cell_outcome: observed used
AronowAudit.P028.independent_arm_response_factor: observed used
AronowAudit.P028.independent_response_cell_mean: observed used
AronowAudit.P028.independent_response_factor: observed used
AronowAudit.P028.missing_moment_difference_bounds: observed used
AronowAudit.P028.missing_probability_as_mean: observed used
AronowAudit.P028.normalized_arm_integral: observed used
AronowAudit.P028.normalized_arm_real: observed used
AronowAudit.P028.normalized_arm_set_integral: observed used
AronowAudit.P028.null_cell_joint_moment: observed used
AronowAudit.P028.observed_y_measurable: observed used
AronowAudit.P028.recorded_joint_moment_bounds: observed used
Source and evidence metadata · sap-2026-11-08-assured-release