Decision Tree Learning
Interpretable Machine Learning: Fundamental Principles and 10 Grand Challenges
Rudin, Cynthia, Chen, Chaofan, Chen, Zhi, Huang, Haiyang, Semenova, Lesia, Zhong, Chudi
Interpretability in machine learning (ML) is crucial for high stakes decisions and troubleshooting. In this work, we provide fundamental principles for interpretable ML, and dispel common misunderstandings that dilute the importance of this crucial topic. We also identify 10 technical challenge areas in interpretable machine learning and provide history and background on each problem. Some of these problems are classically important, and some are recent problems that have arisen in the last few years. These problems are: (1) Optimizing sparse logical models such as decision trees; (2) Optimization of scoring systems; (3) Placing constraints into generalized additive models to encourage sparsity and better interpretability; (4) Modern case-based reasoning, including neural networks and matching for causal inference; (5) Complete supervised disentanglement of neural networks; (6) Complete or even partial unsupervised disentanglement of neural networks; (7) Dimensionality reduction for data visualization; (8) Machine learning models that can incorporate physics and other generative or causal constraints; (9) Characterization of the "Rashomon set" of good models; and (10) Interpretable reinforcement learning. This survey is suitable as a starting point for statisticians and computer scientists interested in working in interpretable machine learning.
Decision Trees and Random Forest
A very popular algorithm, in Machine Learning, is the Decision Tree Classifier. In this article, the Banknote dataset will be used to illustrate the capabilities of this model. A decision tree is a basic machine learning algorithm that can be used for classification problems. From a high level, a decision tree starts with a basic statement at the top of the tree, and then based on if that statement is True or False, it will then move down a different path to the next condition. This will then continue throughout the duration of the model.
Fake News Detection Using Python
This is my first data analysis related video. In this video, I have solved the Fake news detection problem using four machine learning classification algorithms. Hi everyone, This is my first data analysis related video. In this video, I have solved the Fake news detection problem using four machine learning classification algorithms. From this video, you will learn how you can apply Linear regression, Decision Tree classification, Gradient boost classification, and random forest classification model.
Decision Theoretic Bootstrapping
Tavallali, Peyman, Bajgiran, Hamed Hamze, Esaid, Danial J., Owhadi, Houman
The design and testing of supervised machine learning models combine two fundamental distributions: (1) the training data distribution (2) the testing data distribution. Although these two distributions are identical and identifiable when the data set is infinite; they are imperfectly known (and possibly distinct) when the data is finite (and possibly corrupted) and this uncertainty must be taken into account for robust Uncertainty Quantification (UQ). We present a general decision-theoretic bootstrapping solution to this problem: (1) partition the available data into a training subset and a UQ subset (2) take $m$ subsampled subsets of the training set and train $m$ models (3) partition the UQ set into $n$ sorted subsets and take a random fraction of them to define $n$ corresponding empirical distributions $\mu_{j}$ (4) consider the adversarial game where Player I selects a model $i\in\left\{ 1,\ldots,m\right\} $, Player II selects the UQ distribution $\mu_{j}$ and Player I receives a loss defined by evaluating the model $i$ against data points sampled from $\mu_{j}$ (5) identify optimal mixed strategies (probability distributions over models and UQ distributions) for both players. These randomized optimal mixed strategies provide optimal model mixtures and UQ estimates given the adversarial uncertainty of the training and testing distributions represented by the game. The proposed approach provides (1) some degree of robustness to distributional shift in both the distribution of training data and that of the testing data (2) conditional probability distributions on the output space forming aleatory representations of the uncertainty on the output as a function of the input variable.
High number of unique values and tree based models
Having columns of data with high cardinality can adversely affect the performance of your models. The idea of this article stemmed from my personal experience of employing tree based solutions in various projects. In this article I will attempt to show the effects of this on a couple of datasets using the simple decision tree. Cardinality can be defined as the uniqueness of data in the machine learning context. Examples of fields with a high number of unique values include cities, countries, medical diagnosis codes, movie categories on Netflix, flavours of ice cream, etc.
Evidence-Based Policy Learning
Spiess, Jann, Syrgkanis, Vasilis
The past years have seen seen the development and deployment of machine-learning algorithms to estimate personalized treatment-assignment policies from randomized controlled trials. Yet such algorithms for the assignment of treatment typically optimize expected outcomes without taking into account that treatment assignments are frequently subject to hypothesis testing. In this article, we explicitly take significance testing of the effect of treatment-assignment policies into account, and consider assignments that optimize the probability of finding a subset of individuals with a statistically significant positive treatment effect. We provide an efficient implementation using decision trees, and demonstrate its gain over selecting subsets based on positive (estimated) treatment effects. Compared to standard tree-based regression and classification tools, this approach tends to yield substantially higher power in detecting subgroups with positive treatment effects. INTRODUCTION Recent years have seen the development of machine-learning algorithms that estimate heterogeneous causal effects from randomized controlled trials. While the estimation of average effects - for example, how effective a vaccine is overall, whether a conditional cash transfer reduces poverty, or which ad leads to more clicks - can inform the decision whether to deploy a treatment or not, heterogeneous treatment effect estimation allows us to decide who should get treated. These algorithms aim to maximize realized outcomes, and thus focus on assigning treatment to individuals with positive (estimated) treatment effects. Yet in practice, the deployment of assignment policies often only happens after passing a test that the assignment produces a positive net effect relative to some status quo. For example, a drug manufacturer may have to demonstrate that the drug is effective on the target population by submitting a hypothesis test to the FDA for approval.
Interpretable Data-driven Methods for Subgrid-scale Closure in LES for Transcritical LOX/GCH4 Combustion
Chung, Wai Tong, Mishra, Aashwin Ananda, Ihme, Matthias
Many practical combustion systems such as those in rockets, gas turbines, and internal combustion engines operate under high pressures that surpass the thermodynamic critical limit of fuel-oxidizer mixtures. These conditions require the consideration of complex fluid behaviors that pose challenges for numerical simulations, casting doubts on the validity of existing subgrid-scale (SGS) models in large-eddy simulations of these systems. While data-driven methods have shown high accuracy as closure models in simulations of turbulent flames, these models are often criticized for lack of physical interpretability, wherein they provide answers but no insight into their underlying rationale. The objective of this study is to assess SGS stress models from conventional physics-driven approaches and an interpretable machine learning algorithm, i.e., the random forest regressor, in a turbulent transcritical non-premixed flame. To this end, direct numerical simulations (DNS) of transcritical liquid-oxygen/gaseous-methane (LOX/GCH4) inert and reacting flows are performed. Using this data, a priori analysis is performed on the Favre-filtered DNS data to examine the accuracy of physics-based and random forest SGS-models under these conditions. SGS stresses calculated with the gradient model show good agreement with the exact terms extracted from filtered DNS. The accuracy of the random-forest regressor decreased when physics-based constraints are applied to the feature set. Results demonstrate that random forests can perform as effectively as algebraic models when modeling subgrid stresses, only when trained on a sufficiently representative database. The employment of random forest feature importance score is shown to provide insight into discovering subgrid-scale stresses through sparse regression.
Optimal Targeting in Fundraising: A Machine Learning Approach
Cagala, Tobias, Glogowsky, Ulrich, Rincke, Johannes, Strittmatter, Anthony
Fundraising is a costly activity: the largest 25 US charities spend between 5% and 25% of total donations on fundraising expenses (Andreoni and Payne, 2011). These numbers are a matter of concern for two reasons. First, high fundraising costs imply that a smaller proportion of overall donations can finance charitable projects. This effect can lead to an underprovision of the provided goods and services and may, thus, lower welfare if the donors' utility depends on provision levels (Rose-Ackerman, 1982; Name-Correa and Yildirim, 2013). Second, high fundraising costs also matter from the charities' perspectives: it is well documented that donors are averse to financing overhead costs (Tinkelman and Mankaney, 2007; Gneezy et al., 2014). Hence, charities with excessive fundraising expenses will be less successful in raising donations. In conclusion, reducing disproportional fundraising costs can be crucial, both from a welfare and a charity-management perspective. However, while there is a broad literature studying how fundraising instruments such as matching grants and unconditional gifts affect donors' behavior (surveyed by Andreoni and Payne, 2013), previous research has paid less attention to how charities could increase the cost efficacy of fundraising. This paper shifts focus to a novel approach to increase a fundraising campaigns' efficacy: optimal targeting of fundraising activities based on causal machine learning.
Interpretable Machines: Constructing Valid Prediction Intervals with Random Forests
An important issue when using Machine Learning algorithms in recent research is the lack of interpretability. Although these algorithms provide accurate point predictions for various learning problems, uncertainty estimates connected with point predictions are rather sparse. A contribution to this gap for the Random Forest Regression Learner is presented here. Based on its Out-of-Bag procedure, several parametric and non-parametric prediction intervals are provided for Random Forest point predictions and theoretical guarantees for its correct coverage probability is delivered. In a second part, a thorough investigation through Monte-Carlo simulation is conducted evaluating the performance of the proposed methods from three aspects: (i) Analyzing the correct coverage rate of the proposed prediction intervals, (ii) Inspecting interval width and (iii) Verifying the competitiveness of the proposed intervals with existing methods. The simulation yields that the proposed prediction intervals are robust towards non-normal residual distributions and are competitive by providing correct coverage rates and comparably narrow interval lengths, even for comparably small samples.
Machine Learning with ML.NET - Random Forest
One of the most popular ways to build ensembles is to use the same algorithm multiple times but on the different subsets of the training dataset. Techniques that are used for this are called bagging and pasting. The only difference in these techniques is that while building subsets bagging allows training instances to be sampled several times for the same predictor, while pasting is not allowing that. When all algorithms are trained, the ensemble makes a prediction by aggregating the predictions of all algorithms. In the classification case that is usually the hard-voting process, while for the regression average result is taken.