Questions tagged [decision-trees]

A decision tree is a decision support tool that uses a tree-like graph or model of decisions and their possible consequences, including chance event outcomes, resource costs, and utility. It is one way to display an algorithm.

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When should I use Gini Impurity as opposed to Information Gain (Entropy)?

Can someone practically explain the rationale behind Gini impurity vs Information gain (based on Entropy)? Which metric is better to use in different scenarios while using decision trees?
125k views

strings as features in decision tree/random forest

I am doing some problems on an application of decision tree/random forest. I am trying to fit a problem which has numbers as well as strings (such as country name) as features. Now the library, scikit-...
35k views

Why do we need XGBoost and Random Forest?

I wasn't clear on couple of concepts: XGBoost converts weak learners to strong learners. What's the advantage of doing this ? Combining many weak learners instead of just using a single tree ? ...
46k views

Are decision tree algorithms linear or nonlinear

Recently a friend of mine was asked whether decision tree algorithms are linear or nonlinear algorithms in an interview. I tried to look for answers to this question but couldn't find any satisfactory ...
26k views

How is a splitting point chosen for continuous variables in decision trees?

I have two questions related to decision trees: If we have a continuous attribute, how do we choose the splitting value? Example: Age=(20,29,50,40....) Imagine that we have a continuous attribute $f$...
76k views

How to predict probabilities in xgboost using R?

The below predict function is giving -ve values as well so it cannot be probabilities. ...
15k views

Is it necessary to normalize data for XGBoost?

MinMaxScaler() in scikit-learn is used for data normalization (a.k.a feature scaling). Data normalization is not necessary for ...
31k views

XGBRegressor vs. xgboost.train huge speed difference?

If I train my model using the following code: ...
46k views

Should I use a decision tree or logistic regression for classification?

I am working on a classification problem. I have a dataset containing equal numbers of categorical variables and continuous variables. How do I decide which technique to use, between a decision tree ...
38k views

Decision tree vs. KNN

In which cases is it better to use a Decision tree and other cases a KNN? Why use one of them in certain cases? And the other in different cases? (By looking at its functionality, not at the ...
11k views

Decision trees: leaf-wise (best-first) and level-wise tree traverse

Issue 1: I am confused by the description of LightGBM regarding the way the tree is expanded. They state: Most decision tree learning algorithms grow tree by level (depth)-wise, like the ...
472 views

Can gradient boosted trees fit any function?

For neural networks we have the universal approximation theorem which states that neural networks can approximate any continuous function on a compact subset of $R^n$. Is there a similar result for ...
59k views

How to make a decision tree with both continuous and categorical variables in the dataset?

Let's say I have 3 categorical and 2 continuous attributes in a dataset. How do I build a decision tree using these 5 variables? Edit: For categorical variables, it is easy to say that we will split ...
67k views

When to choose linear regression or Decision Tree or Random Forest regression? [closed]

I am working on a project and I am having difficulty in deciding which algorithm to choose for regression. I want to know under what conditions should one choose a <...
30k views

How to normalize data for Neural Network and Decision Forest

I have a data set with 20000 samples, each has 12 different features. Each sample is either in category 0 or 1. I want to train a neural network and a decision forest to categorize the samples so that ...
19k views

Unbalanced classes -- How to minimize false negatives?

I have a dataset that has a binary class attribute. There are 623 instances with class +1 (cancer positive) and 101,671 instances with class -1 (cancer negative). I've tried various algorithms (Naive ...
18k views

Interpreting Decision Tree in context of feature importances

I'm trying to understand how to fully understand the decision process of a decision tree classification model built with sklearn. The 2 main aspect I'm looking at are a graphviz representation of the ...
7k views

Catboost Categorical Features Handling Options (CTR settings)?

I am working with a dataset with large number of categorical features (>80%) predicting a continuous target variable (i.e. Regression). I have been reading quite a bit about ways to handle categorical ...
13k views

How max_features parameter works in DecisionTreeClassifier?

What is the parameter max_features in DecisionTreeClassifier responsible for? I thought it defines the number of features the ...
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Is max_depth in scikit the equivalent of pruning in decision trees?

I was analyzing the classifier created using a decision tree. There is a tuning parameter called max_depth in scikit's decision tree. Is this equivalent of pruning a decision tree? If not, how could I ...
5k views

Why neural networks do not perform well on structured data?

I was recently working on some classification problem where decision trees performed better than neural networks. I had tried various combinations with neural networks altering the number of neurons / ...
25k views

XGBoost for binary classification: choosing the right threshold

I am working on a highly-imbalanced binary-labeled dataset, where number of true labels is just 7% from the whole dataset. But some combination of features could yield higher than average number of ...
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Does feature selections matter to Decision Tree algorithms?

Background: Currently I'm working on my thesis project, which is to build Tree-based ensemble methods for classification on a large data set. Before I started with modeling, I've spent a large amount ...
6k views

Why decision tree needs categorical variable to be encoded?

As per my intuition, decision trees should work better with categorical variables than with continuous variables. If this is the case, why is encoding needed on categorical variables? Can someone give ...
10k views

How to get a confidence score for predictions?

In a regression problem, is it possible to calculate a confidence/reliability score for a certain prediction given models like XGBoost or Neural Networks?
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How to (better) discretize continuous data in decision trees?

Standard decision tree algorithms, such as ID3 and C4.5, have a brute force approach for choosing the cut point in a continuous feature. Every single value is tested as a possible cut point. (By ...
3k views

Minimum number of trees for Random Forest classifier

I am searching for a theoretical or experimental estimation of the lower bound for the number of trees in a Random Forest classifier. I usually test different combinations and select the one that (...
22k views

How to interpret a decision tree correctly?

I'm trying to work out if I'm correctly interpreting a decision tree found online. The dependent variable of this decision tree is Credit Rating which has two classes, Bad or Good. The root of this ...
11k views

Information Gain in R

I found packages being used to calculating "Information Gain" for selecting main attributes in C4.5 Decision Tree and I tried using them to calculating "Information Gain". But the results of ...
153 views

Which ML approach to choose for the game AI when rewards are delayed?

Question: Which Machine Learning approach should I choose for the AI of my computer game, where the actions of the AI do not lead to immediate rewards, but delayed rewards instead? About me: I am a ...
11k views

How to preprocess different kinds of data (continuous, discrete, categorical) before Decision Tree learning

I want to use some Decision Tree learning, such as the Random Forest classifier. I have data of different types: continuous, discrete and categorical. How do I have to preprocess data in order to ...
16k views

Why don't tree ensembles require one-hot-encoding?

I know that models such as random forest and boosted trees don't require one-hot encoding for predictor levels, but I don't really get why. If the tree is making a split in the feature space, then isn'...
1k views

XGBoost and Random Forest: ntrees vs. number of boosting rounds vs. n_estimators

So I understand the main difference between Random Forests and GB Methods. Random Forests grow parallel trees and GB Methods grow one tree for each iteration. However, I am confused on the vocab used ...
1k views

How are samples selected from training data in Xgboost

In Random Forest, each tree is not fed with the full batch of training data, only a sample. How does this work for Xgboost? If this sampling happens as well, how does it work for this ML algorithm?
24k views

How to prevent/tell if Decision Tree is overfitting?

In SKLearn's documentation on Decision Trees, they say we should pay special attention not to overfit the tree. How can we do this? I am aware that using random forests may prevent it, but how do I ...