Recursive Partitioning for Heterogeneous Causal Effects — TEI-tagged view

Susan Athey, Guido Imbens · 2016 · economics · doi:10.1073/pnas.1510489113 · full text at the source · TEI xml · tagged edition · index · concepts · authors
Where this record's text came from. faceted 2026-08 by reading the locally held text (pdftext); every evidence string verified as an exact substring of that text before merging. Extraction is clean apart from mathematical notation and occasional lost spaces (e.g. 'tradeoffbetween', 'meansquared'), which is why quotes were chosen from prose passages. method is recorded as 'simulation' because the only evidence the paper generates about its estimators' performance is a three-design Monte Carlo study; the analytic derivation of the honest criteria is theory rather than proof of a theorem, and no empirical dataset is analysed. Section 8 ('The Literature') distinguishes the approach from several numbered references, but those passages state differences rather than an explicit builds-on/extends/contradicts relation, so only the two unambiguous relations are recorded. The paper's citations are numeric, so relation targets can only be named as the paper itself names them. 2026-08-14, 2026-08-15 and 2026-08-25 schema-0.3 passes: every quote verified as an exact substring of the staged text and anchored at merge time; concept terms verified present; every edge endpoint an existing node. Update, 15 September 2026: EXCEPTION, measured with the merge gate's own predicate (Paper.locate): 1 quote(s) on this record are not found as one exact string in the current staged text - content_tags.findings[0].evidence. The sentence above does not hold for them as written. Where a row records why - the quote is grounded in another copy of the paper, joins two passages with an ellipsis, or differs from the staged text by extraction noise - that note stays on the row.
The quality of the text these quotes were cut from. symbol-font-not-extractable: 33 '(cid:NNN)' glyph-index markers remain in a staged text of 49,356 characters, where the PDF's embedded font had no ToUnicode map. THE QUOTES ON THIS RECORD ARE THE PAPER'S AND THE STAGED COPY IS THE DAMAGED ONE - which is the opposite of the usual case and is why it went unnoticed: one of its 55 live quotes is not an exact substring of this text, and it could NOT be located in it even by aligning the quote's WORD SEQUENCE under this damage, so the defect recorded here is present on the record but does not by itself account for the miss. Not repaired in place: editing the staged text moves every offset after the edit and re-hashes every anchor on the record. Measured at 113aae60fefc3eb1, re-measured unchanged at 54b63482778ddf56.
1 quote on this page breaks a word across a line. The PDF this text was extracted from hyphenated a word at the end of a printed line — adversar- ial, repre- sentations — and the extractor kept the hyphen and the space. The quotes keep them because a quote is reproduced exactly or it proves nothing: the break is the typesetter’s, not the author’s. A search of this page will not find the affected words.
1 quote on this page was cut from a different copy of this article. This project holds two extractions of this paper: the plain text every other quote here is anchored in, and the publisher’s own HTML edition, which we are not licensed to republish. It is verbatim in the second and cannot be found in the first — not because the tagging is wrong, but because the extraction damaged the passage: a page number dropped into the middle of a number, a formula moved out of its sentence, a ligature where two letters belong. The record names the copy for each one. The quote is the paper’s; the extraction is not.
Other fields define these differently the same word, defined another way in another discipline
machine learning 14 fields · false-discovery-rate 6 fields · sample-size 5 fields · coverage 4 fields · null-hypothesis 3 fields · confidence-interval 2 fields · and 3 more →
Tags on this paper every tag the record carries, whether or not the words occur in the text below — a number is how many papers in the corpus carry that tag; a tag with no number is unique to this paper
causal inference4 treatment effect3 machine learning33 regression tree honest estimation adaptive unconfoundedness2 mean-squared error7 coverage4 simulation51

Our tag layer for this paper

Cross-disciplinary analysis
content-tags & facets: phenomenon · claim-type · cross-domain-transfer · mechanism · claim-relation · replication-status · limitation — grounded in the full text
phenomenonheterogeneous treatment effects— “In this paper we study two closely related problems: first, estimating heterogeneity by covariates or features in causal effects in experimental or observational studies, and second, conducting inference about the magnitude of the differences in treatment effects across subsets of the population.”
claim-typemethod— “In this paper we propose methods for estimating heterogeneity in causal effects in experimental and observational studies, and for conducting hypothesis tests about the magnitude of the differences in treatment effects across subsets of the population.”
method — evidence— “To assess the relative performance of the proposed algorithms we carried out a small simulation study with three distinct designs.”
transferfrom statistics / machine learning: regression-tree (recursive partitioning) methods adapted to estimate heterogeneous treatment effects— “Our approach builds on regression tree methods, modified to optimize for goodness of fit in treatment effects”transfers[0]
mechanismhonest estimation: use one sample to construct the tree partition and a separate sample to estimate treatment effects, removing overfitting bias— “one sample is used to construct the partition and another to estimate treatment effects for each subpopulation”mechanisms[0]
builds-on regression tree methods (machine learning)— “Our approach builds on regression tree methods”claim_relations[0]
builds-on standard CART regression trees ([4], [3])— “In this paper, we focus on the analogous goal of deriving a partition of the population according to treatment effect heterogeneity, building on standard regression trees ([4], [3]).”claim_relations[1]
builds-on the Rubin Causal Model / potential outcome framework ([19], [11], [14])— “Causal effects, in the Rubin Causal Model or potential outcome framework we use here ([19], [11], [14]), are comparisons between outcomes we observe and counterfactual outcomes we would have observed under a different regime or treatment.”claim_relations[2]
sense'honest' - A STIPULATED PROPERTY OF DATA USE: a model is honest when the information selecting its structure is not the information estimating its parameters, which is sample splitting and nothing about truthfulness, candour or good faith - all of which the word carries anyway— “We say that a model is “honest” if it does not use the same information for selecting the model structure (in our case, the partition of the covariate space) and for estimation given a model structure”senses[0]
sense'adaptive' - THE NAME GIVEN TO THE ALTERNATIVE: conventional CART, where one sample does both jobs, is labelled adaptive here so that the two can be compared; the word is the paper's, applied to a practice that did not call itself that— “We contrast ‘’honest” estimation with “adaptive” estimation used in conventional CART, where the same data is used to build the partition and estimate leaf effects”senses[1]
sensethe estimand - UNOBSERVABLE FOR EVERY UNIT: unit-level causal effects are not observed for any unit at all, so unlike an ordinary prediction problem there is no held-out truth anywhere in the data against which a per-unit estimate could be scored— “This creates complications for conventional methods because we do not observe unit level causal effects for any unit”senses[2]
controlthree simulation designs differing in whether noise covariates are present and in how covariates enter the treatment effect — held— “We find in the settings we consider that honest estimation results in improvements in fit, in some cases very large improvements, over a more traditional “adaptive” estimation approach.” — rules out that the advantage of honest estimation depends on one particular data-generating design, in particular on the absence of noise covariates— “Design 1 does not have noise covariates.”controls[0]
retractedEVIDENCE CORRECTED (RE-GROUNDED) · honest estimation —contrasted-with→ adaptive — RE-GROUNDED. The old span named only one endpoint. This sentence names both and states the contrast WITH ITS DIRECTION - honest estimation improves on adaptive, not merely differs.— “We contrast ‘’honest” estimation with “adaptive” estimation used in conventional CART, where the same data is used to build the partition and estimate leaf effects”— “We contrast ‘’honest” estimation with “adaptive” estimation”concept_edges[0]
notehonest estimation —contrasted-with→ adaptive — RE-GROUNDS another row of this record: the old span named only ONE endpoint.— “We find in the settings we consider that honest estimation results in improvements in fit, in some cases very large improvements, over a more traditional “adaptive” estimation approach.”concept_edges[2]
outcomecontrol — held— “Design 1 does not have noise covariates.”— “We find in the settings we consider that honest estimation results in improvements in fit, in some cases very large improvements, over a more traditional “adaptive” estimation approach.”controls[0]
for which uselimitation — the precision of honest estimates: THERE IS A LOSS OF PRECISION DUE TO SAMPLE SPLITTING, offset in fit by the elimination of bias— “Although there is a loss of precision due to sample splitting (which reduces sample size in each step of estimation), there is a benefit for fit in terms of eliminating bias that offsets at least part of the cost.”limitations[1]
for which uselimitation — the recommendation itself, with the cost measured: THERE IS A COST TO HONEST ESTIMATION IN TERMS OF MSE-tau, VARYING BY DESIGN AND ESTIMATOR— “The results show that there is a cost to honest estimation in terms of MSEτ , varying by design and estimator.”limitations[2]
for which uselimitation — any application where units interact: the no-interference assumption MAY BE VIOLATED IN SETTINGS WHERE SOME UNITS ARE CONNECTED THROUGH NETWORKS— “This assumption may be violated in settings where some units are connected through networks.”limitations[3]
for which uselimitation — the hybrid variants: WE DO NOT CONSIDER THOSE VARIATIONS IN THIS PAPER— “We do not consider those variations in this paper.”limitations[4]
for which uselimitation — any treatment-effect estimate produced by this method: unit-level causal effects are not observed for any unit, so the target is never available to check an estimate against— “This creates complications for conventional methods because we do not observe unit level causal effects for any unit”limitations[5]
for which uselimitation — the word 'honest' as used throughout this paper: a model is honest if it does not use the same information for selecting the model structure and for estimation given that structure— “We say that a model is “honest” if it does not use the same information for selecting the model structure (in our case, the partition of the covariate space) and for estimation given a model structure”limitations[6]
for which uselimitation — the benefit reported for honest estimation: it is an improvement in confidence-interval coverage, attaining nominal rates, and the authors describe the cost as not much sacrifice in fitting treatment effects— “we show that honest estimation can result in substantial improvements in coverage of confidence intervals, where our method attains nominal coverage rates, without much sacrifice in terms of fitting treatment effects”limitations[7]
for which uselimitation — the contrast drawn here between honest and adaptive estimation: adaptive is the label the authors give conventional CART, in which the same data builds the partition and estimates leaf effects— “We contrast ‘’honest” estimation with “adaptive” estimation used in conventional CART, where the same data is used to build the partition and estimate leaf effects”limitations[8]
replicationuntested
limitationrequires the unconfoundedness (conditional randomization) assumption— “we maintain the assumption of randomization conditional on the covariates”limitations[0]
limitationSample splitting for honest estimation costs precision, which is only partly offset by the removal of bias.— “Although there is a loss of precision due to sample splitting (which reduces sample size in each step of estimation), there is a benefit for fit in terms of eliminating bias that offsets at least part of the cost.”limitations[1]
limitationIn the simulations honest estimation is measurably worse than adaptive estimation on treatment-effect mean-squared error.— “The results show that there is a cost to honest estimation in terms of MSEτ , varying by design and estimator.”limitations[2]
limitationThe no-interference (SUTVA) assumption the methods rest on can fail when units are connected in a network.limitations[3]
limitationHybrid variants (adaptive tree construction combined with honest leaf estimation) are left unexamined.limitations[4]
limitationThe quantity the method estimates is never observed for any unit in the data.limitations[5]
limitationThe paper's central adjective is a stipulated property of data use, not a claim about candour.limitations[6]
limitationThe improvement claimed for honesty is measured in coverage, and the paper names what it costs.limitations[7]
limitationThe comparison class is conventional tree estimation under a name the paper assigns it.
Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher.
limitations[8]
Content tags
content-observations: finding · quantity · variable · definition · key-term — grounded in the full text
findingA data-driven approach partitions the data into subpopulations that differ in the magnitude of their treatment effects, letting the data discover relevant subgroups.
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content_tags.findings[0]
not machine-vouchedfinding — declared-ellipsis - An elided quote: its 2 pieces ('We provide a data- driven approach to pa' ... 'let the data discover relevant subgroups') are each in our copy of the paper (with line-break hyphens, spacing and punctuation set aside), and the quote marks the cut with an ellipsis, so the joined string is in no copy. Located mechanically, piece by piece.content_tags.findings[0]
findingHonest estimation splits the sample: one half builds the partition, the other estimates each subpopulation's treatment effect.
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content_tags.findings[1]
variablecovariates (independent)
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content_tags.variables[0]
variabletreatment effects (dependent)
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content_tags.variables[1]
definitionhonest estimation
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content_tags.definitions[0]
definitionheterogeneous treatment effects
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content_tags.definitions[1]
evidence status notedefinition — QUOTE REPAIRED: the extractor split a hyphen-space and the quote was recorded faithfully with the damage in it, which made it unanchorable. The repaired string is an EXACT SUBSTRING of the staged text - that is why it was accepted, not because a rule produced it. The text as originally recorded is kept in evidence as extracted.content_tags.definitions[1]
key-termstreatment, causal, effects, partition, honest, tree, covariates, estimation, subgroup
Concepts
terms this paper carries, each with the sentence it was cut from — the layer that joins one paper to another. Terms with no quote yet are on CONCEPTS.html.
concepthonest estimation
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concepts[4]
conceptadaptive
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concepts[5]
conceptunconfoundedness
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concepts[6]
conceptmean-squared error
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concepts[7]
conceptcoverage
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concepts[8]
Statistics — cross-field join keys
field-invariant statistical terms, used in their statistical sense (gated on a number / symbol / test). A p-value or a standard deviation means the SAME thing in physics, biology, psychology and sociology — so these are the strongest cross-field join keys. Grounded verbatim.
Bayesian
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content_tags.statistics[0]
confidence-interval CI as written: confidence intervals
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content_tags.statistics[1]
false-discovery-rate FDR as written: multiple testing
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content_tags.statistics[2]
hypothesis-testing as written: hypothesis tests
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content_tags.statistics[3]
evidence status notehypothesis-testing — QUOTE REPAIRED: the extractor split a hyphen-space and the quote was recorded faithfully with the damage in it, which made it unanchorable. The repaired string is an EXACT SUBSTRING of the staged text - that is why it was accepted, not because a rule produced it. The text as originally recorded is kept in evidence as extracted.content_tags.statistics[3]
mean μ as written: mean of
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content_tags.statistics[4]
null-hypothesis H0
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content_tags.statistics[5]
evidence status notenull-hypothesis — THE QUOTE STOPS WHERE THE EXTRACTED TEXT GOES OUT OF ORDER: the extraction splices another line of the page ('If the two leaves are denoted L (Left) and') into this sentence, so the quote ends before that line, at 'the two potential', and the end of the sentence is not quoted.content_tags.statistics[5]
p-value p as written: p-values
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content_tags.statistics[6]
regression β
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content_tags.statistics[7]
evidence status noteregression — QUOTE REPAIRED: the extractor split a hyphen-space and the quote was recorded faithfully with the damage in it, which made it unanchorable. The repaired string is an EXACT SUBSTRING of the staged text - that is why it was accepted, not because a rule produced it. The text as originally recorded is kept in evidence as extracted.content_tags.statistics[7]
sample-size n/N
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content_tags.statistics[8]
t-test t as written: T-statistic
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content_tags.statistics[9]
variance σ²
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content_tags.statistics[10]

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