REVIEW 2 major objections 4 minor 41 references
Bayesian models for missing and misclassified variables using integrated nested Laplace approximations
T0 review · 2 major / 4 minor · reviewed 2026-08-12 · deepseek-v4-flash
Pith's one-line read Bayesian models with misclassified categorical covariates can be fit with INLA by importance-sampling the latent true covariate; a misclassified binary response is handled with a shifted, scaled logit link.
desk verdict Useful, code-bearing adaptation of INLA+importance sampling to misclassification, but the reported credible intervals are built on a quantile-of-mixture shortcut that needs fixing. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The misclassification matrix M, the exposure model logit(p_x) = alpha0 + Z_alpha, and the derived Bernoulli posterior for the latent covariate, whose success probability p_{x|w,Z} is a simple Bayes update of the exposure probability using the misclassification matrix. The marginalization identity pi(theta_y | y,w,Z) = integral pi(theta_y | x,y,Z) pi(x | y,w,Z) dx is approximated by importance sampling, with weights proportional to the conditional marginal likelihood pi(y | x^(j), Z) computed by INLA. For the response case, the central object is the shifted and scaled logit link logit((p_s - (1 - pi00))/(pi11 - (1 - pi00))) = beta0 + Z_i^T beta_z, which converts a misclassified binary response into an ordinary Bernoulli model with a corrected link.
What would settle it
Simulate datasets with a known true binary covariate and misclassification matrix, then run the proposed importance-sampling INLA procedure with a deliberately wrong but plausible misclassification matrix and examine coverage of the posterior intervals for the covariate coefficient across many replications; if coverage drops well below the nominal level, the known-M assumption is demonstrably load-bearing.
Extended reading notes
Core claim
The central claim is that the marginal posterior of the regression coefficients in a model with a misclassified categorical covariate can be approximated as a weighted average of INLA conditional posteriors, with weights given by the normalized conditional marginal likelihoods. The true covariate is treated as a latent Bernoulli variable, sampled from the posterior that combines the exposure model and the misclassification matrix; the conditional model given each sampled covariate is then fitted in INLA. For a misclassified binary response, the paper shows that the observed outcome still follows a Bernoulli model, but with a shifted and scaled logit link that explicitly contains the sensitivity and specificity, so the correction can be implemented without a latent discrete variable, directly in INLA. In the special case where the misclassified variable can be interpreted as a discretization of a latent Gaussian variable with measurement error, the paper shows that the whole model becomes a probit measurement-error model and can be fitted using only INLA.
Load-bearing premise
The load-bearing premise is that the exposure model coefficients and the misclassification probabilities are known in advance; if they are misspecified, the importance-weighted posterior will be biased, and the method offers no internal mechanism to detect or correct that misspecification.
Editorial extensions
If this is right
- A naive regression using the misclassified covariate attenuates the covariate effect, while the proposed importance-sampling correction recovers the true coefficient when the exposure model and misclassification probabilities are correctly specified.
- Missing categorical covariate values can be imputed within the same importance-sampling framework by treating missingness as 50% misclassification, so the exposure model alone determines the sampled value.
- A misclassified binary response can be corrected in INLA with a fixed or uncertain sensitivity and specificity, and the latter can be propagated by averaging over a grid of plausible values.
- When the misclassified binary variable arises from dichotomizing a mismeasured continuous variable, the entire model can be fitted in INLA alone, avoiding the slower importance-sampling loop.
- The choice between differential and nondifferential misclassification can substantially change the estimated coefficients, as the cervical-cancer and herpes example demonstrates.
Reading between the lines
- Because the method treats the exposure model coefficients and the misclassification matrix as known inputs, real applications will likely need sensitivity analyses over these inputs; the paper's grid-weighting idea for response misclassification suggests a natural template for such analyses.
- The block proposal of the entire latent covariate vector is flagged as inefficient; a component-wise or sequential proposal could both speed convergence and open the door to estimating the exposure and misclassification parameters outside INLA.
- The numerical instability of the shifted logit link at low sensitivity and specificity is especially consequential because that is exactly the regime where correcting for misclassification matters most; a more stable reparameterization of the link would expand the method's practical reach.
- The same imputation logic could be extended to models with multiple categorical covariates that are each partially missing or misclassified, since each latent covariate can be sampled and weighted in the same conditional-marginal-likelihood scheme.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper proposes two ways to fit regression models with misclassified categorical variables using the integrated nested Laplace approximation (INLA). For covariate misclassification, the true binary covariate x is treated as latent and sampled from its conditional distribution given the observed misclassified version w and an assumed exposure model; each sampled x is used to fit the model in INLA, and the conditional posterior distributions of the regression coefficients are combined by importance sampling weights proportional to the conditional marginal likelihoods. For response misclassification, the paper derives a modified logit link, called sslogit, that expresses the success probability of the observed response in terms of the true response probability and known sensitivity and specificity, and implements it directly in INLA. The paper also covers missing categorical covariates, a special case where misclassification arises from dichotomizing a mismeasured continuous variable, and illustrates all methods with simulations and two applied examples using the accompanying R package inlamisclass.
Significance. If the proposed methods are correct, they meaningfully extend the class of Bayesian models that can be fit efficiently with INLA to settings with discrete latent variables induced by misclassification and missingness. The paper is accompanied by reproducible code and an R package, which is a practical strength. The response-misclassification link is a clean reparameterization that is straightforward to implement. However, the central covariate-misclassification algorithm has a load-bearing technical flaw in its treatment of posterior quantiles: it averages conditional quantiles rather than computing quantiles of the weighted mixture, which can produce mis-calibrated credible intervals. The method also requires the exposure model and misclassification probabilities to be known, a limitation that is acknowledged but not addressed with sensitivity analyses.
major comments (2)
- [Section 3.2.1, unnumbered display for q_alpha(beta_x | y, w, Z)] The approximation q_alpha(beta_x | y,w,Z) approx sum_j omega_j q_alpha(beta_x | x^(j), y, Z) is not a valid way to compute a quantile of a mixture distribution. If F_j(t) are the conditional posterior CDFs, the mixture CDF is F(t) = sum_j omega_j F_j(t), and the alpha-quantile is F^{-1}(alpha), not sum_j omega_j F_j^{-1}(alpha). Quantiles are nonlinear functionals, so the displayed formula is generally wrong. For example, for two equally weighted conditional posteriors N(-1,1) and N(1,1), the 0.025 quantile of the mixture lies below -1.96, whereas the weighted average of the two 0.025 quantiles equals -1.96, producing an interval that is too narrow. Since Figures 1, 2, 6, and 7 present 95% credible intervals and the manuscript does not state any alternative computation, the reported interval coverage is not guaranteed. The authors should replace this step with numerical inversion of the weighted mixture CDF (or sampling from the mixture) and update all simulation and application results accordingly.
- [Section 3.2.1 and Algorithm 1] The covariate-misclassification method assumes that the exposure-model coefficients alpha and the misclassification matrix M are known; this is stated in the text but the implications are not explored. In the simulations and applications, alpha and M are either known by design or chosen hypothetically (as in the birth weight example), and no sensitivity analysis is reported for plausible misspecification of these inputs. Because in many real applications these quantities are not known precisely, the paper would be substantially strengthened by a systematic study of how mis-specified alpha or M affect the resulting posterior distributions and credible intervals, or by a demonstration of how these parameters can be estimated within the importance-sampling framework.
minor comments (4)
- [Section 5.1] The statement 'With 200,000 iterations, each model took us around seven hours to run' should clarify whether this is per simulated dataset or for the entire set of ten datasets, and whether all models were run sequentially or in parallel.
- [Section 3.2.2] The notation in this section introduces x_c and x_d in addition to the earlier binary x, which can be confusing; a brief sentence clarifying that x_c is the latent continuous covariate and x_d is its discretized version would help the reader.
- [Section 4.1] The grid approximation for p(py | s) uses weights omega(pi00(k), pi11(k)) derived from a joint distribution for sensitivity and specificity, but the manuscript does not specify how this joint distribution is chosen or whether a product of independent Beta distributions is intended; the supporting information should be referenced within the main text.
- [Abstract and Section 7] The paper repeatedly refers to 'detailed code in the supporting information' and a GitHub repository; for archival purposes, the code should be deposited in a permanent repository with a versioned DOI, since GitHub links may not be stable.
Circularity Check
No significant circularity: the covariate-misclassification posterior is derived from a standard Bayes/marginal-likelihood identity, and the response-misclassification link is an algebraic reparameterization; self-citations are implementation groundwork, not load-bearing.
full rationale
The central derivation in Section 3.2.1 starts from the exact identity pi(theta_y | y,w,Z) = integral pi(theta_y | x,y,Z) pi(x | y,w,Z) dx and approximates it by importance sampling with weights proportional to the conditional marginal likelihoods pi(y | x(j),Z). This is a standard Monte Carlo identity, not a fitted quantity renamed as a prediction. The exposure-model coefficients alpha and misclassification matrix M are stated assumptions ('we assume the parameters of the exposure model and the misclassification probabilities to be known'), and the paper explicitly notes that estimating them would require an MCMC extension. The response-misclassification result in Section 4 follows by algebra: p_si = pi11 p_yi + (1-pi00)(1-p_yi) is inverted to define the shifted, scaled logit link in Eq. (7); this is a reparameterization of the same Bernoulli model, presented as an implementation device for INLA rather than as an empirical prediction. The paper relies on earlier work by the same group (Berild et al. 2022 for INLA-within-importance-sampling; Muff et al. 2015 for measurement-error INLA; Skarstein et al. 2023 for missing-data extensions), but these are external, published methodological building blocks and are not used as a uniqueness theorem or to forbid alternatives. All simulation studies compare against known true parameter values, providing external checks. The only notable technical concern in the manuscript, approximating posterior quantiles of the mixture by weighted averages of conditional quantiles, is a mathematical correctness issue (quantiles are not linear functionals of mixture components), not a circularity: the claimed approximation does not equal its input by construction, and the paper's core weighting identity does not depend on it. For these reasons the circularity score is low.
Assumptions & free parameters
free parameters (3)
- Misclassification probabilities (sensitivity, specificity or matrix entries) =
Birth weight example: pi00=0.95, pi11=0.80; HSV example: differential matrices bM1 and bM0
- Exposure model coefficients alpha =
Birth weight case 2: alpha0=-0.4, alpha_z=0.02; simulations: alpha=(-0.5, 0.25)
- Measurement error standard deviation sigma_u in the discretized Gaussian model =
Fixed to 1 in the simulation of Section 5.2
assumptions (5)
- domain assumption The exposure model for the latent covariate is known and correctly specified (Eq. 3)
- domain assumption Covariate misclassification is nondifferential given the true covariate, i.e., the observed misclassified variable is conditionally independent of the response given the true covariate (Section 2, paragraph on nondifferential misclassification)
- domain assumption INLA provides accurate approximations to conditional posterior marginals and marginal likelihoods
- domain assumption The importance sampling proposal is adequate with a finite number of samples
- domain assumption Missing categorical covariate values are missing completely at random (Section 5.3)
Cite this review
Pith. "Pith review of Bayesian models for missing and misclassified variables using integrated nested Laplace approximations." pith.science (2026). https://pith.science/paper/FMQ6NDKI
@misc{pith2026241116311,
author = {Pith},
title = {Pith review of: Bayesian models for missing and misclassified variables using integrated nested Laplace approximations},
year = {2026},
howpublished = {\url{https://pith.science/paper/FMQ6NDKI}},
note = {Machine review of arXiv:2411.16311}
}
read the original abstract
Misclassified variables used in regression models, either as a covariate or as the response, may lead to biased estimators and incorrect inference. Even though Bayesian models to adjust for misclassification error exist, it has not been shown how these models can be implemented using integrated nested Laplace approximation (INLA), a popular framework for fitting Bayesian models due to its computational efficiency. Since INLA requires the latent field to be Gaussian, and the Bayesian models adjusting for covariate misclassification error necessarily introduce a latent categorical variable, it is not obvious how to fit these models in INLA. Here, we show how INLA can be combined with importance sampling to overcome this limitation. We also discuss how to account for a misclassified response variable using INLA directly without any additional sampling procedure. The proposed methods are illustrated through a number of simulations and applications to real-world data, and all examples are presented with detailed code in the supporting information.
Figures
Figures from the paper (4 more)
Reference graph
Works this paper leans on
-
[1]
O., Martino, S., Gómez-Rubio, V., and Rue, H
Berild, M. O., Martino, S., Gómez-Rubio, V., and Rue, H. (2022). Importance sampling with the integrated nested laplace approximation. Journal of Computational and Graphical Statistics , 31(4):1225--1237
work page 2022
-
[2]
Bollinger, C. R. and van Hasselt , M. (2017). A B ayesian analysis of binary misclassification. Economics Letters , 156:68--73
work page 2017
-
[3]
Buonaccorsi, J. P., Laake, P., and Veierød, M. B. (2005). On the effect of misclassification on bias of perfectly measured covariates in regression. Biometrics , 61(3):831--836
work page 2005
-
[4]
Carroll, R., Gail, M. H., and Lubin, J. H. (1993). Case-control studies with errors in covariates. Journal of the American Statistical Association , 88(421):185--199
work page 1993
-
[5]
Carroll, R., Ruppert, D., Stefanski, L., and Crainiceanu, C. (2006). Measurement Error in Nonlinear Models: A Modern Perspective, Second Edition . Chapman & Hall/CRC Monographs on Statistics & Applied Probability. CRC Press
work page 2006
-
[6]
Chu, R., Gustafson, P., and Le, N. (2010). Bayesian adjustment for exposure misclassification in case-control studies. Statistics in Medicine , 29(9):994--1003
work page 2010
-
[7]
T., Checkoway, H., McMichael, A
Copeland, K. T., Checkoway, H., McMichael, A. J., and Holbrook, R. H. (1977). Bias due to misclassification in the estimation of relative risk. American Journal of Epidemiology , 105(5):488--495
work page 1977
-
[8]
Felsenstein, J. (2005). Using the quantitative genetic threshold model for inferences between and within species. Philosophical Transactions of the Royal Society B: Biological Sciences , 360(1459):1427--1434
work page 2005
Show all 41 references
-
[9]
J., and Charlton, C
Goldstein, H., Browne, W. J., and Charlton, C. (2018). A B ayesian model for measurement and misclassification errors alongside missing data, with an application to higher education participation in A ustralia. Journal of Applied Statistics , 45(5):918--931
2018
-
[10]
Greenland, S. (1980). The effect of misclassification in the presence of covariates. American Journal of Epidemiology , 112(4):564--569
1980
-
[11]
Gustafson, P. (2003). Measurement Error and Misclassification in Statistics and Epidemiology: Impacts and Bayesian Adjustments . Chapman & Hall/CRC Interdisciplinary Statistics. CRC Press
2003
-
[12]
Gustafson, P. (2005). On model expansion, model contraction, identifiability and prior information: Two illustrative scenarios involving mismeasured variables. Statistical Science , 20(2):111--140
2005
-
[13]
Gómez-Rubio, V. (2020). Bayesian Inference with INLA . CRC Press
2020
-
[14]
Gómez-Rubio , V., Cameletti , M., and Blangiardo , M. (2022). Missing data analysis and imputation via latent G aussian M arkov random fields. SORT-Statistics and Operations Research Transactions , 46(2):217--244
2022
-
[15]
and Rue, H
Gómez-Rubio , V. and Rue, H. (2018). Markov chain M onte C arlo with the integrated nested L aplace approximation. Statistics and Computing , 28:1033--1051
2018
-
[16]
Hausman, J., Abrevaya, J., and Scott-Morton, F. (1998). Misclassification of the dependent variable in a discrete-response setting. Journal of Econometrics , 87(2):239--269
1998
-
[17]
and Lemeshow, S
Hosmer, D. and Lemeshow, S. (2000). Applied Logistic Regression, 2nd Edition . Wiley Series in Probability and Statistics. Wiley
2000
-
[18]
Höfler, M. (2005). The effect of misclassification on the estimation of association: a review. International Journal of Methods in Psychiatric Research , 14(2):92--101
2005
-
[19]
Högg, T. (2018). Bayesian adjustments for disease misclassification in epidemiological studies of health administrative databases, with applications to multiple sclerosis research . phdthesis, University of British Columbia
2018
-
[20]
H., Shaw, P
Keogh, R. H., Shaw, P. A., Gustafson, P., Carroll, R. J., Deffner, V., Dodd, K. W., Küchenhoff, H., Tooze, J. A., Wallace, M. P., Kipnis, V., and Freedman, L. S. (2020). Stratos guidance document on measurement error and misclassification of variables in observational epidemio...
2020
-
[21]
M., and Lesaffre, E
Küchenhoff, H., Mwalili, S. M., and Lesaffre, E. (2006). A general method for dealing with misclassification in regression: The misclassification SIMEX . Biometrics , 62:85--96
2006
-
[22]
Liu, J., Gustafson, P., and Huo, D. (2016). Bayesian adjustment for the misclassification in both dependent and independent variables with application to a breast cancer study. Statistics in Medicine , 35(23):4252--4263
2016
-
[23]
B., Bondy, M., Shields, P
Luta, G., Ford, M. B., Bondy, M., Shields, P. G., and Stamey, J. D. (2013). Bayesian sensitivity analysis methods to evaluate bias due to misclassification and missing data using informative priors and external validation data. Cancer Epidemiology , 37(2):121--126
2013
-
[24]
Magder, L. S. and Hughes, J. P. (1997). Logistic regression when the outcome is measured with uncertainty. American Journal of Epidemiology , 146(2):195--203
1997
-
[25]
Muff, S., Riebler, A., Held, L., Rue, H., and Saner, P. (2015). Bayesian analysis of measurement error models using integrated nested L aplace approximations. Journal of the Royal Statistical Society: Series C (Applied Statistics) , 64(2):231--252
2015
-
[26]
M., Lesaffre, E., and Declerck, D
Mwalili, S. M., Lesaffre, E., and Declerck, D. (2005). A B ayesian ordinal logistic regression model to correct for interobserver measurement error in a geographical oral health study. Journal of the Royal Statistical Society: Series C (Applied Statistics) , 54(1):77--93
2005
-
[27]
J., Martín, J., Mutsvari, T., and Lesaffre, E
Naranjo, L., Pérez, C. J., Martín, J., Mutsvari, T., and Lesaffre, E. (2019). A B ayesian approach for misclassified ordinal response data. Journal of Applied Statistics , 46(12):2198--2215
2019
-
[28]
J., Chin, Y.-M., and Stamey, J
Nelson, T., Song, J. J., Chin, Y.-M., and Stamey, J. D. (2018). Bayesian correction for misclassification in multilevel count data models. Computational and Mathematical Methods in Medicine , 2018:e3212351
2018
-
[29]
Neuhaus, J. M. (1999). Bias and efficiency loss due to misclassified responses in binary regression. Biometrika , 86(4):843--855
1999
-
[30]
D., Soares, P., and Neuhaus, J
Paulino, C. D., Soares, P., and Neuhaus, J. (2003). Binomial Regression with Misclassification . Biometrics , 59(3):670--675
2003
-
[31]
Reade-Christopher, S. J. and Kupper, L. L. (1991). Effects of exposure misclassification on regression analyses of epidemiologic follow-up study data. Biometrics , 47(2):535--548
1991
-
[32]
and Stone, R
Ren, D. and Stone, R. A. (2007). A B ayesian adjustment for covariate misclassification with correlated binary outcome data. Journal of Applied Statistics , 34(9):1019--1034
2007
-
[33]
and Gilks, W
Richardson, S. and Gilks, W. R. (1993a). A B ayesian approach to measurement error problems in epidemiology using conditional independence models. American Journal of Epidemiology , 138(6):430--442
1993
-
[34]
and Gilks, W
Richardson, S. and Gilks, W. R. (1993b). Conditional independence models for epidemiological studies with covariate measurement error. Statistics in Medicine , 12(18):1703--1722
1993
-
[35]
Rue, H., Martino, S., and Chopin, N. (2009). Approximate B ayesian inference for latent G aussian models by using integrated nested L aplace approximations. Journal of the Royal Statistical Society: Series B (Statistical Methodology) , 71(2):319--392
2009
-
[36]
and Zhou, Y
Rutkowski, L. and Zhou, Y. (2015). Correcting measurement error in latent regression covariates via the MC - SIMEX method. Journal of Educational Measurement , 52(4):359--375
2015
-
[37]
Skarstein, E., Martino, S., and Muff, S. (2023). A joint B ayesian framework for missing data and measurement error using integrated nested L aplace approximations. Biometrical Journal , 65(8):2300078
2023
-
[38]
H., King, C
Tang, L., Lyles, R. H., King, C. C., Celentano, D. D., and Lo, Y. (2015). Binary regression with differentially misclassified response and exposure variables. Statistics in Medicine , 34(9):1605--1620
2015
-
[39]
and Akakpo, R
Xia, M. and Akakpo, R. M. (2022). A Bayesian approach to simultaneous adjustment of misclassification and missingness in categorical covariates. Statistical Methods in Medical Research , 31(8):1449--1469
2022
-
[40]
and Gustafson, P
Xia, M. and Gustafson, P. (2016). Bayesian regression models adjusting for unidirectional covariate misclassification. The Canadian Journal of Statistics / La Revue Canadienne de Statistique , 44(2):198--218
2016
-
[41]
Yi, G. (2017). Statistical Analysis with Measurement Error or Misclassification: Strategy, Method and Application . Springer Series in Statistics. Springer
2017
Reviewed August 12, 2026 · model on record in the stance chip above.
Discussion (0). Continue with ORCID to comment.