What is Classification

Understanding Classification in Artificial Intelligence

In the field of artificial intelligence, classification is a vital function that allows machines to group and categorize data. It is a process of assigning predefined categories or labels to new data points based on their features or characteristics. Classification plays a critical role in various applications, including image recognition, natural language processing, customer segmentation, spam filtering, fraud detection, and more.

In this article, we will delve deeper into classification in artificial intelligence, exploring its various types, methods, and algorithms.

Types of Classification

Classification in artificial intelligence can be classified into three different types, which include:

  • Binary Classification
  • Multi-Class Classification
  • Multi-Label Classification

Binary Classification: Binary classification is the simplest type of classification that involves two distinct classes. In this type of classification, the machine learning model is trained to differentiate between these two classes by analyzing the features of the data points. For example, binary classification can be used for identifying whether an email is spam or not.

Multi-Class Classification: In multi-class classification, the machine learning model is trained on multiple classes or categories. Instead of predicting one of the two outcomes as in binary classification, it needs to predict one of the several possible outcomes. For example, multi-class classification can be used in image recognition, where the model needs to categorize an image as a person, animal, vehicle, or something else.

Multi-Label Classification: In multi-label classification, the machine learning model is trained to assign multiple labels or categories to a single data point. For example, in sentiment analysis, a text document can have multiple sentiments like happiness, sadness, anger, etc.

Methods of Classification

Various methods are used for classification, which can be classified into two types, namely:

  • Supervised Learning
  • Unsupervised Learning

Supervised Learning: Supervised learning is a type of classification where the machine learning model is trained on labeled data. Labeled data refers to the data points that are pre-classified into different categories. This labeled data is then used to train the machine learning model, and once the model is trained, it can classify new data points into one of the predefined categories.

Supervised learning algorithms are further classified into two categories:

  • Parametric Models
  • Non-Parametric Models

Parametric Models: Parametric models make assumptions about the data distribution and rely on statistical techniques to find the best parameters that fit the model. Some of the popular parametric models include Naive Bayes, Logistic Regression, and Linear Discriminant Analysis.

Non-Parametric Models: Non-parametric models do not make assumptions about the data distribution and can work with any type of data. These models usually rely on the distance or similarity measures to classify the data points. Some of the popular non-parametric models include K-Nearest Neighbors and Decision Trees.

Unsupervised Learning: Unsupervised learning is a type of classification where the machine learning model is trained on unlabeled data. This means that there are no predefined categories or labels assigned to the data points. Instead, the machine learning model needs to identify patterns and group the data points based on their similarities or differences.

Unsupervised learning algorithms are further classified into two categories:

  • Clustering Algorithms
  • Association Rule Learning

Clustering Algorithms: Clustering algorithms group the data points into clusters based on their similarities or differences. The two most popular clustering algorithms include K-Means and Hierarchical Clustering.

Association Rule Learning: Association rule learning is a type of unsupervised learning that deals with finding associations or relationships between different data points. The most popular association rule learning algorithm is Apriori algorithm.

Algorithms used in Classification

There are various algorithms used in classification, which can be classified into two categories based on their approach, namely:

  • Probabilistic Algorithms
  • Non-Probabilistic Algorithms

Probabilistic Algorithms: Probabilistic algorithms use statistical techniques to model the probability distribution of each class present in the training dataset. Using Bayes' theorem or other statistical methods, they calculate the conditional probability of each class given the input attributes. Then the algorithm predicts the class with the highest probability. Some of the popular probabilistic algorithms include Naive Bayes, Bayesian Networks, and Logistic Regression.

Non-Probabilistic Algorithms: Non-probabilistic algorithms use different approaches to classify the data points. These algorithms do not rely on probability distributions to model the data but instead use other techniques like decision trees, neural networks, and k-nearest neighbors. Some of the popular non-probabilistic algorithms include Decision Trees, Random Forest, K-Nearest Neighbors, and Artificial Neural Networks.


Classification is a widely-used function in artificial intelligence that helps organize and categorize data. Its applications vary from natural language processing to image recognition to fraud detection. In this article, we explored the different types of classification, methods, and algorithms used in artificial intelligence. While there are many algorithms and methods available, the choice of which to use depends on the type of data, the task, and the desired outcome.