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What are Decision Trees | Understand Decision Tree Terminologies

What are Decision Trees | Understand Decision Tree Terminologies

By Upskill Campus
Published Date:   28th October, 2024 Uploaded By:    Ankit Roy
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Decision trees are like a flowchart that helps you make choices based on information. They are used in many areas, like computers learning and finding patterns in data. In addition, they make it easy to understand how different things are connected. In this article, we will describe what decision trees are, how they work, their good and bad points, and where they are used.

 

What is a Decision Tree?

 

Decision trees are powerful flowcharts that guide you in making informed choices based on relevant data. They are used to put things into groups or to predict numbers. In addition, they are shaped like a tree, with starting points, branches, and ending points. The starting point splits the information into different parts. The branches then check the information to make more groups. The ending points show all the possible results.
 

Decision trees work by breaking down information into smaller and smaller parts. They search for the best way to split the information so that the groups are as similar as possible. This process is repeated until all or most of the information is sorted into different groups. If the groups are bigger, it can be easier to make accurate predictions. To prevent this, decision trees are usually kept small. This is the idea that simple explanations are often better than complicated ones.
 

To make the decision tree even better, a process called pruning can be used to remove unnecessary parts. In addition, this can help prevent the tree from making mistakes. Another way to improve decision trees is to use a random forest. This is a group of decision charts that work together to make predictions.

 

Decision Tree Terminologies

 

Here, we will discuss various terminologies regarding the decision tree model.
 

  • Root Node: The topmost node that represents the entire dataset. It splits into sub-nodes based on feature conditions.
  • Leaf Node (Terminal Node): Nodes that do not split further and represent the final output or class label in classification tasks.
  • Decision Node: Nodes that split the dataset based on a condition. Each condition represents a decision rule.
  • Branches: Connections between nodes that represent the outcome of a decision or test.
  • Splitting: The process of dividing a node into two or more sub-nodes based on a condition. Splits are based on features that provide the most information gain.
  • Pruning: Reducing the size of the tree by removing branches or nodes that add little value. This helps prevent overfitting.

 

Procedure of Decision Making Tree

 

The decision tree is essentially a flowchart that represents a series of decisions and their possible outcomes. When you want to use a decision tree to predict something, you start at the top (the root). The tree asks you questions about the information you have. Based on your answers, it directs you to different branches and eventually leads you to a decision (a leaf).


Here's how it works:

  • First, the tree starts with a main question.
  • After that, you answer the question based on the information you have.
  • Then, the answer leads you to the next question or decision.
  • At last, keep answering questions and following branches until you reach the end.

 

Decision Tree Diagram

 

When building a decision tree, the key is to select questions that effectively divide your data into meaningful groups. This process, known as attribute selection, ensures that the tree makes accurate predictions. When it comes to decision trees, two key approaches stand out: Information Gain and Gini Index. These methods are essential for optimizing decision-making and enhancing model accuracy.
 

  1. Information Gain
  • Concept: Measures how much a question helps you learn something new about the data.
  • Calculation: Compares the entropy (a measure of disorder) of the data before and after splitting based on the attribute.
  • Goal: Choose questions that result in the largest decrease in entropy, indicating that the attribute provides significant information about the target variable.
     
  1. Gini Index
  • Concept: Measures the impurity or randomness in the data.
  • Calculation: Calculates the probability of a randomly chosen instance being incorrectly classified.
  • Goal: Select attributes with the lowest Gini index, as these have the least impurity and are more likely to lead to pure subsets.
     
  1. Pruning: Making Your Decision Tree Smaller

Sometimes, decision trees can get too big and complicated. Moreover, this can make them harder to understand and can even lead to mistakes. To fix this, we can "prune" the tree, which means removing unnecessary parts. As a result, this helps us get a smaller, simpler, and better decision tree.


Example:

Imagine you're trying to decide whether to buy a house based on its price, location, and number of bedrooms. Using information gain, you might find that the price attribute provides the most information about whether to buy or not. You would then split the data based on price.

 

 

Best Decision Tree Software

 

Decision trees are a great way to visualize decisions and their possible outcomes. Here are some popular tools you can use to create them:


Professional Tools
 

  • EdrawMax: Offers pre-designed templates and is easy to use.
  • SmartDraw: Another user-friendly tool with many diagram options.
  • Lucidchart: Great for collaboration and has free options for basic decision trees.
  • ZingTree: Designed for call centers but can be used for decision trees.
  • Sketchboard: Offers a freeform drawing environment for a more creative approach.
  • Creately: A collaboration tool that allows you to create decision trees from scratch.


Presentation Tools
 

  • SlideTeam: Provides pre-made PowerPoint slides for decision trees.
  • Excel: Can used to create basic decision trees using SmartArt diagrams.
  • MindMeister: Designed for mind maps but can adapt to decision trees.

Choosing the right tool depends on your needs and preferences. Consider factors like ease of use, features, collaboration capabilities, and pricing.

 

Decision Tree Examples

 

Decision trees are a helpful tool for making choices in project management. They can help you decide if a project should continue or be changed based on different factors.
 

  • Project Management Decision Tree: This type of decision tree can help you figure out if you have enough resources to finish a project on time. Moreover, it can help you decide if you should keep going or make some changes.
  • Product Launch Decision Tree: This decision tree can help you decide if your product is ready to be launched. In addition, it helps you check if the market is right if you can make enough of the product, and if your marketing plan is good.
  • Analysis Decision Tree: This decision tree can help you choose the best way to analyze data. It helps you pick the right method based on the kind of data you have and what you want to find out.

 

Advantages and Disadvantages of Decision-making Tree

 

Advantages of Decision Trees
 

  • Easy to understand and interpret: The structure of a decision tree is intuitive.
  • Can handle both numerical and categorical data: Decision trees can work with different types of data.
  • No need for feature scaling: Decision trees don't require normalization or standardization of features.
  • Robust to outliers: Decision trees can handle outliers without being significantly affected.


Disadvantages of Decision Trees

  • Prone to overfitting: Decision trees can become too complex and fit the training data too closely, leading to poor performance on new data.
  • Sensitive to small changes in data: Small changes in the data can lead to significant changes in the structure of the tree.


To mitigate these issues, techniques like pruning and ensemble methods (e.g., random forests) are often used.

 

Our Learner Also Reads: What is Performance Marketing | Performance Marketing Explained

 

Concluding Words

 

Decision trees are a flowchart that helps you make choices based on information. Moreover, they are used in many areas, like computers learning and finding patterns in data. They make it easy to understand how different things are connected. In this article, we have talked about what decision trees are, how they work, and where they are used.

 

Frequently Asked Questions

 
Q1. How to create a decision tree in Word?

Ans. To make a decision tree in Word, you can use the drawing tools:

 - First, start a new document > Go to Insert > Click Shapes.

 - Then, choose a shape and draw it.

 - Lastly, connect the shapes with lines > Add text to the shapes.


Q2. Why is a decision tree used?

Ans. Decision trees are like a flowchart that helps you make choices based on information. They used to put things into groups or to predict numbers. Apart from that, they can help you predict what will happen next.

 

About the Author

Upskill Campus

UpskillCampus provides career assistance facilities not only with their courses but with their applications from Salary builder to Career assistance, they also help School students with what an individual needs to opt for a better career.

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