REVIEW 2 major objections 4 minor 54 references
This paper proves that AIPW confidence intervals in randomized controlled trials reach nominal coverage at essentially the classical root-n rate when the outcome model is estimated at root-n speed with sub-Weibull tails, and that cross-fitt
Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →
T0 review · deepseek-v4-flash
2026-08-03 14:50 UTC pith:45SZ4UNV
load-bearing objection Real first result on AIPW Wald-CI coverage with estimated variance, but the near-root-n rate is conditional on sub-Weibull assumptions that are only partially verified. the 2 major comments →
Model-Agnostic Bounds for Augmented Inverse Probability Weighted Estimators' Wald-Confidence Interval Coverage in Randomized Controlled Trials
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The central claim is that the error in coverage probability of a Wald interval based on an AIPW estimator with an estimated variance can be bounded non-asymptotically by terms governed by the L2 error of the outcome-model estimator, the complexity of the function class containing it, and the bias of the plug-in variance estimator. Under the paper's sub-Weibull tail conditions, the bound for the cross-fit estimator is O(K^{1/2} r_hat_1(n)(log n)^{...} + ... + K sqrt(log n/n)), which is root-n up to log factors when r_hat_1(n)=n^{-1/2}. A separate theorem shows |sigma_dagger,a - sigma_#,a| is quadratic in the L2 error when the deterministic approximation Q_#,a is chosen as the mean of the esti
What carries the argument
The argument runs through the transformed outcome T_a(Q)(x,a,y)=1(a=a')/pi*(a'|x)(y-Q(x))+Q(x), whose sample mean is the AIPW estimator and whose variance defines the oracle variance sigma^2_#,a. A sample-size-dependent deterministic function Q_#,a, typically the mean of the black-box estimator, absorbs finite-sample bias. Coverage is then bounded by combining a delta-method lemma for coverage probabilities with the classical Berry-Esseen theorem on the linearized sample mean, empirical-process bounds that are sharp for VC and VC-hull classes, and tail bounds on the nuisance estimator's L2 error and on the plug-in variance estimator's deviation from its expectation.
Load-bearing premise
The headline near-root-n rate rests on Conditions 7 and 8, which require the L2 error of the black-box outcome-model estimator (and a related moment) to have approximate sub-Weibull tails; the paper verifies these only for series regression, not for the flexible pipelines used in its simulation.
What would settle it
Run the simulation in the paper with an outcome model whose L2 error is known to decay at n^{-1/4} and has heavy-tailed fluctuations; if the cross-fit Wald interval's coverage does not exceed nominal while the plug-in variance exceeds the oracle variance, the variance-bias mechanism fails. Alternatively, compute empirical tail probabilities of ||Q_hat_{k,a}-Q_#,a||_2 / r_hat_1(n) for a chosen learner; if they decay more slowly than sub-Weibull, the claimed root-n log coverage rate cannot hold.
If this is right
- If the bounds are right, cross-fitting improves Wald-CI coverage even when Donsker conditions hold, because its variance estimator tends to overestimate the oracle variance.
- For outcome model estimators converging at root-n speed with sub-Weibull tails, the coverage error of cross-fit AIPW intervals is comparable to the best-known rate for the sample mean, up to log factors.
- Non-cross-fit AIPW intervals built on highly flexible outcome models can undercover because the plug-in variance underestimates, even though the estimator is asymptotically normal.
- The variance-bias term is nearly second order in the L2 nuisance error for known propensity scores, so it does not dominate the coverage rate.
- There is a potential trade-off: using a more flexible outcome model improves efficiency but slows the convergence of variance bias and hence of coverage.
Where Pith is reading between the lines
- Inference: A practitioner could use these bounds as a diagnostic: if a black-box outcome estimator's L2 error and tail behavior can be estimated on splits, the formulas give a concrete prediction of whether cross-fit or single-fit intervals will over- or undercover.
- Inference: In observational studies, where the propensity score must be estimated, the near-quadratic variance-bias cancellation may break down, so the qualitative conclusions about cross-fitting could differ.
- Inference: The sign predictions for variance bias are testable in a small simulation: compute the oracle variance for Q_#,a as the Monte Carlo mean of the outcome estimator and compare with the average plug-in variance; if the sign pattern disagrees, the mechanism proposed here is incomplete.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. This paper develops Berry-Esseen-type bounds for the coverage of Wald confidence intervals based on augmented inverse probability weighted (AIPW) estimators of counterfactual means in randomized controlled trials, with the asymptotic variance estimated by plug-in. The cross-fit version (Theorem 1 / Theorem S1) gives a bound of order (K^{2/3} E||Qhat_k,a−Q#,a||_2^2/n)^{1/3} + sqrt(K log n/n), which improves to K^{1/2} rhat_1(n) polylog + rhat_2(n) polylog + K sqrt(log n/n) under approximate sub-Weibull tail Conditions 7–8. The non-cross-fit version (Theorem 3 / Theorem S3) has an additional dependence on the uniform entropy integral of the nuisance function class. Theorems 2 and 4 bound the bias of the plug-in variance estimator relative to an oracle variance based on a deterministic approximation Q#,a, showing the bias is second-order when Q#,a is the mean of the nuisance estimator (Condition 9). Proposition 1 and Section 4 argue that cross-fitting overestimates and non-cross-fitting may underestimate the oracle variance; a simulation with Super Learner and highly adaptive lasso nuisance estimators illustrates the theory, including severe undercoverage of a non-cross-fit flexible AIPW estimator.
Significance. If correct, this is a useful addition to the finite-sample inference literature for semiparametric estimators: to this reviewer's knowledge it is the first treatment of Wald-CI coverage convergence with an estimated variance for flexible AIPW estimators in RCTs. The paper's division of labor between a proved non-asymptotic supplement (Theorems S1–S4) and readable asymptotic versions in the main text is a strength, as is the variance-bias decomposition in Theorem 2: the quadratic-rate bias under Condition 9 is a non-obvious consequence of the known propensity score. The simulation is transparent, and the Discussion candidly lists open issues (conservative empirical-process bounds, the heuristic status of the non-cross-fit under-estimation argument, and the open question of choosing K). The main limitation — the unverified scope of Conditions 7–8 for the black-box estimators used in the simulation, and hence the conditional nature of the headline root-n rate — is only partly acknowledged; the revisions below should make the scope of the headline claims precise.
major comments (2)
- [Section 3.1, Condition 8 (and Supplement S2)] The passage after Condition 8 claims that, by Lemma S6, the numerator in Condition 8 'has a tail similar to the L2(P*)-distance' and that Condition 8 'may hold with rhat_2 = rhat_1' under Condition 7. Lemma S6 bounds only the second moment: E[{P*(T_a(Qhat)^2 − E_Qhat[T_a(Qhat)^2])}^2] ≤ 16M^2((1−τπ)/τπ)^2 E||Qhat−Q#,a||^2. A second-moment bound yields at most a polynomial (Chebyshev) tail, not the sub-Weibull decay required by Condition 8; moreover the expression in Lemma S6 involves pointwise evaluations of Qhat, not merely its L2 distance. The same unsupported inference is used in Section S2 to assert Conditions 8/12 for series regression from Proposition S1. Because the 'root-n up to a log' version of Theorem 1 requires Conditions 7 and 8 jointly, Condition 8 is a genuinely additional high-level assumption. Please either prove a real tail bound under Condition 7 (which would require m
- [Section 3.3, second paragraph (and Discussion)] The text claims the bias term φ(zα)zα(σ†,a−σ#,a)/σ#,a 'has a faster convergence rate than the right-hand side ... regardless of ... whether Q#,a is chosen to yield a faster rate.' This is not supported by Theorems 1–2. Put r = E||Qhat_k,a−Q#,a||^2 ≍ n^{−2s}. Theorem 1's RHS is O((r/n)^{1/3}+sqrt(log n/n)); Theorem 2 without Condition 9 gives |σ†,a−σ#,a| = O(sqrt(r)+n^{−1}). For s < 1/2, n^{−s} dominates both n^{−(2s+1)/3} and n^{−1/2}, so the bias term is the leading term in the coverage expansion — precisely in the slow-convergence regime emphasized by Proposition 1 for cross-fit variance overestimation. Even under Condition 9, the bias n^{−2s} dominates (r/n)^{1/3} when s < 1/4. The stated theorems remain valid, but the quoted claim and the Discussion's assertion that 'this bias is not a first-order term' require qualification by Condition 9 and an explicit rate condition (e.g., r = o(
minor comments (4)
- [Condition 11] The displayed tail bound reads exp(˜c1 t^{˜q1}) in the text; as written, the tail probability grows with t. This is evidently a typo for exp(−˜c1 t^{˜q1}); Conditions 8 and 12 show the minus sign.
- [Section 3.1, before Theorem 1] 'The proof of of this theorem' — duplicate 'of'.
- [Proposition 1, Eqs. (3)–(4)] The Θ+(...) notation is used for two separate nonnegative-order terms, one of which is subtracted. The sign and order of the difference are determined only when one term dominates. Please clarify, since Eqs. (3)–(4) as written are easy to misread as an order statement for the full difference.
- [Figure S1 caption] 'Subfigures (A) and (B) are for the cases with and without approximate sub-Weibull conditions 7 and 8, respectively' appears reversed: panel (A) corresponds to the case without the sub-Weibull conditions and panel (B) to the case with them, matching the rates derived in Section S3.
Circularity Check
No circularity: the coverage bounds follow from Berry-Esseen and empirical-process arguments, and the oracle Q# is a post-hoc decomposition target rather than a fitted prediction.
full rationale
The central derivation is self-contained. Theorem 1/3 are proved from the Berry-Esseen theorem, Hall's delta method for CI coverage, Taylor expansion, and Chernozhukov--Chetverikov--Kato empirical-process bounds; the variance-bias results in Theorems 2/4 follow from explicit projection identities (S2) and (S4), not from the target coverage statement. Q# is defined after the fact as E[Qhat] or Q* (Section 2), so E||Qhat-Q#||^2 is an input convergence rate, and the bound legitimately inherits it; the sign of sigma^2_dagger - sigma^2_# is a computed decomposition (Proposition 1), not an assumed conclusion. The only self-citation, Qiu (2024), is a passing counterexample in the introduction and is not load-bearing. The real caveats are scope/verification issues, not circularity: Condition 8 is stated as 'may hold' from Condition 7 via Lemma S6, but Lemma S6 only bounds a variance and not a sub-Weibull tail, so the fast root-n-up-to-log rate is not verified for the Super Learner/HAL pipelines in Section 5; and Section 6 concedes the empirical-process bounds may be conservative and that the variance-bias term is not first-order. These affect the strength of the model-agnostic claim but do not make any derivation equivalent to its inputs.
Axiom & Free-Parameter Ledger
free parameters (3)
- r̂_1(n), r̂_2(n) (and tildes) — nuisance tail-rate functions =
unspecified; O(n^{-1/2}) in the best case
- δ, δ′ balance parameters =
chosen per Corollary 1 as powers of E||Q̃_a−Q#,a||_2^2 or r̃_1(n)(log n)^{1/q}
- Q# deterministic oracle approximation =
either Q* or E[Q̂]
axioms (7)
- standard math Berry-Esseen theorem for i.i.d. sample means
- standard math Gaussian approximation bounds for empirical processes (Chernozhukov et al. 2014, Theorems 5.1/5.2)
- domain assumption Condition 10: bounded uniform entropy integral / Donsker-type class F with J(1,F,M)<∞
- ad hoc to paper Conditions 7/8 (and 11/12): approximate sub-Weibull tails of nuisance estimator
- domain assumption Condition 6: exchangeable equal-size sample splitting with identically distributed fold estimators
- domain assumption Conditions 1–5: nonzero variance, finite third moment, positivity, bounded outcome model, higher-moment bounds
- domain assumption Condition 9/13: Q# is Q* or the mean of the nuisance estimator
read the original abstract
Nonparametric estimators, such as the augmented inverse probability weighted (AIPW) estimator, have become increasingly popular in causal inference. Numerous nonparametric estimators have been proposed, but they are all asymptotically normal with the same asymptotic variance under similar conditions, leaving little guidance for practitioners to choose an estimator. In this paper, I focus on another important perspective of their asymptotic behaviors beyond asymptotic normality, the convergence of the Wald-confidence interval (CI) coverage to the nominal coverage. Such results have been established for simpler estimators (e.g., the Berry-Esseen Theorem), but are lacking for nonparametric estimators. I consider a simple but practical setting where the AIPW estimator based on a black-box nuisance estimator, with or without cross-fitting, is used to estimate the average treatment effect in randomized controlled trials. I derive non-asymptotic Berry-Esseen-type bounds on the difference between Wald-CI coverage and the nominal coverage. I also analyze the bias of variance estimators, showing that the cross-fit variance estimator might overestimate while the non-cross-fit variance estimator might underestimate, which might explain why cross-fitting has been empirically observed to improve Wald-CI coverage even if both estimators converge to the same asymptotic normal distribution.
Figures
Reference graph
Works this paper leans on
-
[1]
Ballinari, D. and Bearth, N. (2024). Improving the Finite Sample Performance of Double/Debiased Machine Learning with Propensity Score Calibration . arXiv preprint arXiv:2409.04874v1
Pith/arXiv arXiv 2024
-
[2]
and Van Der Laan , M
Benkeser, D. and Van Der Laan , M. (2016). The highly adaptive lasso estimator . In 2016 IEEE international conference on data science and advanced analytics (DSAA) , pages 689--696. IEEE
2016
-
[3]
Bentkus, V., Gotze, F., and Tikhomirov, A. (1997). Berry-Esseen bounds for statistics of weakly dependent samples . Bernoulli , 3(3):329--349
1997
-
[4]
Bhattacharya, R. N. and Ghosh, J. K. (2007). On the Validity of the Formal Edgeworth Expansion . The Annals of Statistics , 6(2):434--451
2007
-
[5]
J., Gotze, F., and van Zwet, W
Bickel, P. J., Gotze, F., and van Zwet, W. R. (2007). The Edgeworth Expansion for U -Statistics of Degree Two . The Annals of Statistics , 14(4):1463--1484
2007
-
[6]
and Yu, B
B \" u hlmann, P. and Yu, B. (2003). Boosting with the L2 loss: Regression and classification . Journal of the American Statistical Association , 98(462):324--339
2003
-
[7]
Callaert, H., Janssen, P., and Veraverbeke, N. (2007). An Edgeworth Expansion for U -Statistics . The Annals of Statistics , 8(2):299--312
2007
-
[8]
and White, H
Chen, X. and White, H. (1999). Improved rates and asymptotic normality for nonparametric neural network estimators . IEEE Transactions on Information Theory , 45(2):682--691
1999
-
[9]
Chernozhukov, V., Chetverikov, D., Demirer, M., Duflo, E., Hansen, C., and Newey, W. (2017). Double/debiased/Neyman machine learning of treatment effects . American Economic Review , 107(5):261--265
2017
-
[10]
Chernozhukov, V., Chetverikov, D., Demirer, M., Duflo, E., Hansen, C., Newey, W., and Robins, J. (2018). Double/debiased machine learning for treatment and structural parameters . Econometrics Journal , 21(1):C1--C68
2018
-
[11]
Chernozhukov, V., Chetverikov, D., and Kato, K. (2014). Gaussian approximation of suprema of empirical processes . Annals of Statistics , 42(4):1564--1597
2014
-
[12]
K., and Singh, R
Chernozhukov, V., Newey, W. K., and Singh, R. (2023). A simple and general debiased machine learning theorem with finite-sample guarantees . Biometrika , 110(1):257--264
2023
-
[13]
and Van Der Laan , M
Gruber, S. and Van Der Laan , M. J. (2010). A targeted maximum likelihood estimator of a causal effect on a bounded continuous outcome . International Journal of Biostatistics , 6(1)
2010
-
[14]
and Van Der Laan , M
Gruber, S. and Van Der Laan , M. J. (2014). Targeted minimum loss based estimation of a causal effect on an outcome with known conditional bounds . International Journal of Biostatistics , 8(1)
2014
-
[15]
Guo, A., Benkeser, D., and Nabi, R. (2023). Targeted Machine Learning for Average Causal Effect Estimation Using the Front-Door Functional . arXiv preprint arXiv:2312.10234v1
Pith/arXiv arXiv 2023
-
[16]
Hall, P. (1992). The Bootstrap and Edgeworth Expansion . Springer Series in Statistics. Springer New York, New York, NY
1992
-
[17]
Hejazi, N., Coyle, J., and van der Laan, M. (2020). hal9001: Scalable highly adaptive lasso regression in R . Journal of Open Source Software , 5(53):2526
2020
-
[18]
Jirak, M. (2016). Berry-esseen theorems under weak dependence . Annals of Probability , 44(3):2024--2063
2016
-
[19]
Jirak, M. (2023). A Berry-Esseen bound with (almost) sharp dependence conditions . Bernoulli , 29(2):1219--1245
2023
-
[20]
Kennedy, E. H. (2022). Semiparametric doubly robust targeted double machine learning: a review . arXiv preprint arXiv:2203.06469v2
Pith/arXiv arXiv 2022
-
[21]
Kosorok, M. R. (2008). Introduction to Empirical Processes and Semiparametric Inference , volume 77 of Springer Series in Statistics . Springer New York
2008
-
[22]
Levy, J. (2018). An Easy Implementation of CV-TMLE . arXiv preprint arXiv:1811.04573v2
Pith/arXiv arXiv 2018
-
[23]
V., Hejazi, N
Li, H., Rosete, S., Coyle, J., Phillips, R. V., Hejazi, N. S., Malenica, I., Arnold, B. F., Benjamin-Chung, J., Mertens, A., Colford, J. M., van der Laan, M. J., and Hubbard, A. E. (2022). Evaluating the robustness of targeted maximum likelihood estimators via realistic simulations in nutrition intervention trials . Statistics in Medicine , 41(12):2132--2165
2022
-
[24]
Liu, L., Mukherjee, R., and Robins, J. M. (2020). On Nearly Assumption-Free Tests of Nominal Confidence Interval Coverage for Causal Parameters Estimated by Machine Learning . Statistical Science , 35(3):518--539
2020
-
[25]
Liu, L., Mukherjee, R., and Robins, J. M. (2023). Can we falsify the justification of the validity of Wald confidence intervals of doubly robust functionals, without assumptions? arXiv preprint arXiv:2306.10590v1
Pith/arXiv arXiv 2023
-
[26]
Long, J. S. and Ervin, L. H. (2000). Using Heteroscedasticity Consistent Standard Errors in the Linear Regression Model . American Statistician , 54(3):217--224
2000
-
[27]
Moore, K. L. and van der Laan, M. J. (2009). Covariate adjustment in randomized trials with binary outcomes: Targeted maximum likelihood estimation . Statistics in Medicine , 28(1):39--64
2009
-
[28]
I., Yu, Y
Naimi, A. I., Yu, Y. H., and Bodnar, L. M. (2024). Pseudo-Random Number Generator Influences on Average Treatment Effect Estimates Obtained with Machine Learning . Epidemiology
2024
-
[29]
Neyman, J. (1923). Sur les applications de la th \' e orie des probabilit \' e s aux exp \' e riences agricoles: Essay des principles. (Excerpts reprinted and translated to English, 1990) . Statistical Science , 5:463--472
1923
-
[30]
V., van der Laan, M
Phillips, R. V., van der Laan, M. J., Lee, H., and Gruber, S. (2023). Practical considerations for specifying a super learner . International Journal of Epidemiology , 52(4):1276--1285
2023
-
[31]
Qiu, H. (2024). Non-plug-in estimators could outperform plug-in estimators: a cautionary note and a diagnosis . Epidemiologic Methods , 13(1):1--11
2024
-
[32]
Quintas-Martinez, V. (2022). Finite-Sample Guarantees for High-Dimensional DML . arXiv preprint arXiv:2206.07386v1
Pith/arXiv arXiv 2022
-
[33]
Robins, J. (1986). A new approach to causal inference in mortality studies with a sustained exposure period-application to control of the healthy worker survivor effect . Mathematical Modelling , 7(9-12):1393--1512
1986
-
[34]
Robins, J. M. and Ritov, Y. (1997). Toward a curse of dimensionality appropriate (CODA) asymptotic theory for semi-parametric models . Statistics in Medicine , 16(1-3):285--319
1997
-
[35]
M., Rotnitzky, A., and Zhao, L
Robins, J. M., Rotnitzky, A., and Zhao, L. P. (1994). Estimation of regression coefficients when some regressors are not always observed . Journal of the American Statistical Association , 89(427):846--866
1994
-
[36]
M., Rotnitzky, A., and Zhao, L
Robins, J. M., Rotnitzky, A., and Zhao, L. P. (1995). Analysis of semiparametric regression models for repeated outcomes in the presence of missing data . Journal of the American Statistical Association , 90(429):106--121
1995
-
[37]
and Van Der Laan , M
Rosenblum, M. and Van Der Laan , M. J. (2009). Using regression models to analyze randomized trials: Asymptotically valid hypothesis tests despite incorrectly specified models . Biometrics , 65(3):937--945
2009
-
[38]
Rubin, D. B. (1974). Estimating causal effects of treatments in randomized and nonrandomized studies . Technical Report 5
1974
-
[39]
Rytgaard, H. C. W., Eriksson, F., and Van der Laan , M. (2021). Estimation of time-specific intervention effects on continuously distributed time-to-event outcomes by targeted maximum likelihood estimation . arXiv preprint arXiv:2106.11009v1
Pith/arXiv arXiv 2021
-
[40]
Saco, G. (2025). Finite-Sample Failures and Condition-Number Diagnostics in Double Machine Learning . arXiv preprint arXiv:2512.07083v1
arXiv 2025
-
[41]
M., Song, W., Kempker, R., and Benkeser, D
Schader, L. M., Song, W., Kempker, R., and Benkeser, D. (2024). Don't let your analysis go to seed: on the impact of random seed on machine learning-based causal inference . Epidemiology
2024
-
[42]
Shi, L. and Ding, P. (2022). Berry-Esseen bounds for design-based causal inference with possibly diverging treatment levels and varying group sizes . arXiv preprint arXiv:2209.12345v4
Pith/arXiv arXiv 2022
-
[43]
Smith, M. J., Phillips, R. V., Maringe, C., and Fernandez, M. A. L. (2024). Performance of Cross-Validated Targeted Maximum Likelihood Estimation . arXiv preprint arXiv:2409.11265v1
Pith/arXiv arXiv 2024
-
[44]
Tran, L., Petersen, M., Schwab, J., and van der Laan, M. J. (2023). Robust variance estimation and inference for causal effect estimation . Journal of Causal Inference , 11(1)
2023
-
[45]
Tran, L., Yiannoutsos, C., Wools-Kaloustian, K., Siika, A., Van Der Laan , M., and Petersen, M. (2019). Double Robust Efficient Estimators of Longitudinal Treatment Effects: Comparative Performance in Simulations and a Case Study . International Journal of Biostatistics , 15(2)
2019
-
[46]
van der Laan, L., Lin, Z., Carone, M., and Luedtke, A. (2024a). Stabilized Inverse Probability Weighting via Isotonic Calibration . arXiv preprint arXiv:2411.06342v1
-
[47]
van der Laan, L., Luedtke, A., and Carone, M. (2024b). Automatic doubly robust inference for linear functionals via calibrated debiased machine learning . arXiv preprint arXiv:2411.02771v1
-
[48]
van der Laan, M. (2023). Higher Order Spline Highly Adaptive Lasso Estimators of Functional Parameters: Pointwise Asymptotic Normality and Uniform Convergence Rates . arXiv preprint arXiv:2301.13354v1
Pith/arXiv arXiv 2023
-
[49]
J., Polley, E
Van Der Laan , M. J., Polley, E. C., and Hubbard, A. E. (2007). Super learner . Statistical Applications in Genetics and Molecular Biology , 6(1)
2007
-
[50]
Van der Laan , M. J. and Rose, S. (2018). Targeted Learning in Data Science . Springer
2018
-
[51]
and Wellner, J
van der Vaart, A. and Wellner, J. (1996). Weak Convergence and Empirical Processes: With Applications to Statistics . Springer Series in Statistics. Springer, New York, NY
1996
-
[52]
Wainwright, M. J. (2019). High-dimensional statistics: A non-asymptotic viewpoint . Cambridge University Press
2019
-
[53]
Zhilova, M. (2020). Nonclassical Berry–Esseen inequalities and accuracy of the bootstrap . Annals of Statistics , 48(4):1922--1939
2020
-
[54]
Zhilova, M. (2022). New Edgeworth-Type Expansions With Finite Sample Guarantees . Annals of Statistics , 50(5):2545--2561
2022
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.