Selection bias is a difficult yet widespread problem in causal discovery, occurring whenever non-random selection processes lead to data that is not representative of the underlying populations. Due to its practical importance, related works have been proposed to address the problem under local [Versteeg et al., 2022] or interventional settings [Dai et al., 2025a], but general algorithms for observational data remain elusive. In this paper, we focus on truncated data (hard selection), and provide a general result for Additive Noise Models (ANM). We show that score-based methods are a surprisingly suitable candidate due to a special property of the score function (∇logp(x)): deterministic truncation preserves both the score of the joint distribution as well as the Jacobian of the score. While established score-matching algorithms still fail in most settings, we actively leverage this observation to propose a new method for causal discovery that is robust under truncated data with ANMs. Overall, our approach offers a general, robust solution that is agnostic to external information about the selection process and still achieves comparable performance to the state-of-the-art approaches when selection is not present.
Figures & tables
ANM Assumption
LiNGAM
CAM-UV
SCORE
NoGAM
CHess (Ours)
Nonlinear Gaussian
Linear non-Gaussian
Nonlinear non-Gaussian
Hard Selection (Truncation)
∗
Table 1: Identifiability guarantees of causal discovery methods across ANM assumptions. denotes full DAG identifiability; denotes no guarantee. LiNGAM ( Shimizu et al., 2006 ; Shimizu et al., 2011 ) only deals with linear non-Gaussian ANMs, SCORE ( Rolland et al., 2022 ) requires nonlinear mechanisms with Gaussian noise. NoGAM ( Montagna et al., 2025 ) extends SCORE to arbitrary noise distributions. CAM-UV ( Maeda and Shimizu, 2021 ) additionally handles latent confounders under nonlinear separable (CAM) assumptions. SCORE can handle latent hard selection bias in both Gaussian and non-Gaussian cases, which is not discussed in the original paper but is one of the surprising findings in this work ( ∗ ) . Our method (CHess) is the only method that is resilient to hard selection under all the above ANMs. Linear Gaussian models are known to be not identifiable beyond the Markov equivalence class ( Peters and Bühlmann, 2014 ) thus omitted in the table.
Figure 1: In the subgraph, the sink node Xc is only d-connected to its own noise Nc after conditioning on X\PAc , while Xp is d-connected to Np and Nc after conditioning on X\PAp∪X\CHp .
Setting
Sink rank
Non-sink rank
Gap
Linear Gaussian
0
0
0 (not identifiable)
Linear non-Gaussian
1
≥2
≥1
Nonlinear Gaussian
0
≥1
≥1
Nonlinear non-Gaussian
1
≥2
≥1
Table 2: Rank of M_{i}^{\mathrm{cond}}{\color[rgb]{0,0,0}(z)} for sink vs. non-sink nodes across different ANM settings.
d=5 , gumbel
d=10 , gumbel
fraction
ρ=1.0
ρ=0.1
ρ=0.05
ρ=1.0
ρ=0.1
ρ=0.05
SCORE
0.57 ( ± 0.25)
0.37 ( ± 0.17)
0.41 ( ± 0.14)
0.65 ( ± 0.12)
0.46 ( ± 0.11)
0.45 ( ± 0.10)
DAS
0.57 ( ± 0.25)
0.37 ( ± 0.17)
0.41 ( ± 0.14)
0.66 ( ± 0.11)
0.48 ( ± 0.12)
0.49 ( ± 0.10)
NoGAM
0.81 ( ± 0.21)
0.40 ( ± 0.16)
0.40 ( ± 0.14)
0.78 ( ± 0.16)
0.47 ( ± 0.14)
0.45 ( ± 0.11)
CAM
0.31 ( ± 0.20)
0.18 ( ± 0.14)
0.19 ( ± 0.12)
0.23 ( ± 0.08)
0.22 ( ± 0.11)
0.19 ( ± 0.12)
DirectLiNGAM
0.99 ( ± 0.03)
0.64 ( ± 0.14)
0.65 ( ± 0.16)
0.98 ( ± 0.03)
0.56 ( ± 0.05)
0.54 ( ± 0.07)
Table 3: F1 (Arrow) for Linear-nG (gumbel), d=5 and d=10
Method
ρ=1 ( n=373 )
ρ=0.1
SCORE
0.28 ( ± 0.05)
0.29 ( ± 0.05)
DAS
0.19 ( ± 0.10)
0.23 ( ± 0.08)
NoGAM
0.29 ( ± 0.04)
0.30 ( ± 0.06)
CAM
0.40 ( ± 0.08)
0.28 ( ± 0.09)
PC
0.25 ( ± 0.09)
0.23 ( ± 0.07)
FCI
0.13 ( ± 0.04)
0.14 ( ± 0.11)
Table 4: F1 (Arrow) on Sachs Dataset for ρ=1 (downasmpled) and ρ=0.1
Appendix figures & tables20 assets
Supplementary material from the paper’s appendix.
Appendix
Setting
sink rank
Non-sink rank
Gap
Linear + Gaussian
1
1
0 (not identifiable)
Linear + non-Gaussian
1
≥1+∣\CHl∣
∣\CHj∣≥1
Nonlinear + Gaussian
≤∣\PAl∣+1
≤∣\PAl∣+∣\CHl∣+1
∣\PAj∣+∣\CHj∣−∣\PAl∣
Nonlinear + non-Gaussian
≤∣\PAl∣+1
≤∣\PAl∣+∣\CHl∣+1
∣\PAj∣+∣\CHj∣−∣\PAl∣
Appendix
Table 5: Rank of Mj for sink vs. non-sink nodes across different ANM settings.
True
Estimated
Adjacency
Arrowhead
a←b
a←b
TP
TP, TN
a→b
TP
FP, FN
a — b
TP
FN
ab
FN
FN
ab
a←b
FP
FP
a→b
FP
FP
Appendix
Table 6: Metrics used for evaluation. Precision=TP/(TP+FP), Recall=TP/(TP+FN).
Causal discovery methods commonly assume that all data is independently and identically distributed (i.i.d.) and that there are no unmeasured variables affecting the system. In practice, these assumptions are often violated, leading to inaccurate inference. In this paper, we study how to identify hidden confounding and selection biases from causal mechanism shifts. In particular, we show that structural biases lead to dependent mechanism shifts. That is, by considering for which variables the mechanisms change given data from different environments, we can tell which variables are unbiased, which are subject to hidden confounding, and which are undergoing selection bias. We formalize this into an empirically testable criterion based on mutual information, and show under which conditions it identifies structural biases. To tell which nodes are subject to what kind of bias, we introduce the StruBI algorithm. Experiments on synthetic and real-world data show that StruBI works well in practice, accurately recovering affected variable sets and types of biases, outperforming the state-of-the-art by a wide margin.
Praharsh Nanavati, Jilles Vreeken, David Kaltenpoth
While causal discovery methods have matured for complete data, such algorithms for handling missing values remain limited. We establish general sufficient conditions under which causal graphs remain identifiable (i.e., uniquely determined from the available data distribution) under various missingness categories, including Missing Not At Random, and provide a framework to extend correctness guarantees from causal discovery algorithms for complete data to missing data settings. Our results show that identifiability of causal graphs with no unobserved confounders is preserved when (1) missingness mechanisms do not causally interact, (2) no variable directly causes its own missingness, and (3) either faithfulness holds for missingness mechanisms, or they follow generalized linear models. Guided by these theoretical results, we introduce two asymptotically correct algorithms for Additive Noise Models (ANMs) that recover the underlying causal graph and provide consistent parameter estimates.
Oregon State University, Causal Intelligence and Reasoning Lab, Corvallis, USA · RIKEN Advanced Intelligence Project, Causal Inference Team, Tokyo, Japan · The University of Osaka, Reasoning for Intelligence Department, Osaka, Japan +1
Count data pose a challenge for score-matching-based causal discovery: derivatives are unavailable, and simply replacing them with finite differences does not generally suffice for causal discovery. We generalize SCORE's constant-curvature criterion (Rolland et al., 2022) by conditioning on the node's value, yielding the conditional curvature score (CCS) for ordering. We also extend curvature-based parent recovery through the off-diagonal curvature score (OCS), enabling directed acyclic graph (DAG) recovery with both scores constructed from score functions for continuous data and concrete scores for counts. In the bivariate setting, zero CCS exactly characterizes a semiparametric generalized linear model (GLM) conditional form in which the conditional family need not be specified in advance, unlike in classical GLMs. For bivariate semiparametric GLM DAGs under our regularity condition, canonical-parameter nonlinearity is necessary and sufficient for identifiability. In multivariate DAGs, this nonlinearity enables DAG recovery through CCS and OCS. Our framework identifies a new class of semiparametric GLM DAGs that strictly contains the nonlinear Gaussian ANM class identified by SCORE. We introduce DISCO (DIscrete SCOre), a count-DAG recovery algorithm that estimates CCS and OCS using discrete diffusion. Experiments demonstrate accurate DAG recovery across Poisson, negative binomial, binomial, and mixed-family settings, as well as scalability to 1,000-node DAGs on a single GPU.
Euijong Song, Hyewon Park, Gunwoong Park
Department of Statistics Seoul National University, Korea · Interdisciplinary Program in Artificial Intelligence; Institute for Data Innovation in Science, Seoul National University, Korea