Regression
Toward Explainable AI for Regression Models
In addition to the impressive predictive power of machine learning (ML) models, more recently, explanation methods have emerged that enable an interpretation of complex non-linear learning models such as deep neural networks. Gaining a better understanding is especially important e.g. for safety-critical ML applications or medical diagnostics etc. While such Explainable AI (XAI) techniques have reached significant popularity for classifiers, so far little attention has been devoted to XAI for regression models (XAIR). In this review, we clarify the fundamental conceptual differences of XAI for regression and classification tasks, establish novel theoretical insights and analysis for XAIR, provide demonstrations of XAIR on genuine practical regression problems, and finally discuss the challenges remaining for the field.
Artificial intelligence in clinical research of cancers
As a result, AI excels at handling large volumes and complex data, and identifying characteristic from the data, which the human brain cannot recognize. Although AI has been rapidly incorporated into oncologic research, the development of AI solutions is still in its infancy. Only a few AI-based applications have been approved for use in practice, e.g.
Doubly-Valid/Doubly-Sharp Sensitivity Analysis for Causal Inference with Unmeasured Confounding
Dorn, Jacob, Guo, Kevin, Kallus, Nathan
We study the problem of constructing bounds on the average treatment effect in the presence of unobserved confounding under the marginal sensitivity model of Tan (2006). Combining an existing characterization involving adversarial propensity scores with a new distributionally robust characterization of the problem, we propose novel estimators of these bounds that we call "doubly-valid/doubly-sharp" (DVDS) estimators. Double sharpness corresponds to the fact that DVDS estimators consistently estimate the tightest possible (i.e., sharp) bounds implied by the sensitivity model even when one of two nuisance parameters is misspecified and achieve semiparametric efficiency when all nuisance parameters are suitably consistent. Double validity is an entirely new property for partial identification: DVDS estimators still provide valid, though not sharp, bounds even when most nuisance parameters are misspecified. In fact, even in cases when DVDS point estimates fail to be asymptotically normal, standard Wald confidence intervals may remain valid. In the case of binary outcomes, the DVDS estimators are particularly convenient and possesses a closed-form expression in terms of the outcome regression and propensity score. We demonstrate the DVDS estimators in a simulation study as well as a case study of right heart catheterization.
Preserving gauge invariance in neural networks
Favoni, Matteo, Ipp, Andreas, Müller, David I., Schuh, Daniel
In these proceedings we present lattice gauge equivariant convolutional neural networks (L-CNNs) which are able to process data from lattice gauge theory simulations while exactly preserving gauge symmetry. We review aspects of the architecture and show how L-CNNs can represent a large class of gauge invariant and equivariant functions on the lattice. We compare the performance of L-CNNs and non-equivariant networks using a non-linear regression problem and demonstrate how gauge invariance is broken for non-equivariant models.
Data blurring: sample splitting a single sample
Leiner, James, Duan, Boyan, Wasserman, Larry, Ramdas, Aaditya
Suppose we observe a random vector $X$ from some distribution $P$ in a known family with unknown parameters. We ask the following question: when is it possible to split $X$ into two parts $f(X)$ and $g(X)$ such that neither part is sufficient to reconstruct $X$ by itself, but both together can recover $X$ fully, and the joint distribution of $(f(X),g(X))$ is tractable? As one example, if $X=(X_1,\dots,X_n)$ and $P$ is a product distribution, then for any $m
Toward Explainable AI for Regression Models
Letzgus, Simon, Wagner, Patrick, Lederer, Jonas, Samek, Wojciech, Müller, Klaus-Robert, Montavon, Gregoire
In addition to the impressive predictive power of machine learning (ML) models, more recently, explanation methods have emerged that enable an interpretation of complex non-linear learning models such as deep neural networks. Gaining a better understanding is especially important e.g. for safety-critical ML applications or medical diagnostics etc. While such Explainable AI (XAI) techniques have reached significant popularity for classifiers, so far little attention has been devoted to XAI for regression models (XAIR). In this review, we clarify the fundamental conceptual differences of XAI for regression and classification tasks, establish novel theoretical insights and analysis for XAIR, provide demonstrations of XAIR on genuine practical regression problems, and finally discuss the challenges remaining for the field.
Fish Weight Prediction (Regression Analysis for beginners) -- Part 1
Today we will predict(estimate) the weight of the fish based on species name of fish, vertical length, diagonal length, cross length, height, and diagonal width using linear models. I will introduce the top town approach to solving the problem, which I explained in the previous article. First In part 1.1 I will build a model and then in part 1.2 I will try to explain how each algorithm and methods work. This is a regression analysis problem for beginners. Understanding the main principles and methods of building this kind of problem will help to build your own ML regression model such as (house price prediction, etc.)
Understanding Tree Models
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Loss functions to evaluate Regression Models
The objective of any machine learning model is to understand and learn patterns from the data which can further be used to make predictions or answer questions or simply just understand the underlying pattern in the data that is otherwise not evident candidly. Most of the time, the learning part is iterative. A model learns some patterns from the data, we test it against some new data that the model did not encounter during training, we see how good or how bad a job it did, we tweak and adjust some parameters, then we put it to test again. This process is repeated until we are presented with a model that is good enough (Although, some real world models can just be satisfactory and make a world of difference). The part where we evaluate and test our model is where the loss functions come into play.
Predicting treatment effects from observational studies using machine learning methods: A simulation study
Smith, Bevan I., Chimedza, Charles
Measuring treatment effects in observational studies is challenging because of confounding bias. Confounding occurs when a variable affects both the treatment and the outcome. Traditional methods such as propensity score matching estimate treatment effects by conditioning on the confounders. Recent literature has presented new methods that use machine learning to predict the counterfactuals in observational studies which then allow for estimating treatment effects. These studies however, have been applied to real world data where the true treatment effects have not been known. This study aimed to study the effectiveness of this counterfactual prediction method by simulating two main scenarios: with and without confounding. Each type also included linear and non-linear relationships between input and output data. The key item in the simulations was that we generated known true causal effects. Linear regression, lasso regression and random forest models were used to predict the counterfactuals and treatment effects. These were compared these with the true treatment effect as well as a naive treatment effect. The results show that the most important factor in whether this machine learning method performs well, is the degree of non-linearity in the data. Surprisingly, for both non-confounding \textit{and} confounding, the machine learning models all performed well on the linear dataset. However, when non-linearity was introduced, the models performed very poorly. Therefore under the conditions of this simulation study, the machine learning method performs well under conditions of linearity, even if confounding is present, but at this stage should not be trusted when non-linearity is introduced.