Ensemble Methods involve algorithms that create multiple models and then combine them to produce improved results. They’re like a team of experts, employing diversity to solve complex problems. These methods generally yield more reliable and robust output than a single model approach.
Let’s imagine we are trying to guess the number of candies in a jar. One person’s guess might be off, but if we let a lot of people guess, their average guess will usually be more accurate. Ensemble methods in AI do a similar thing, they take a bunch of ‘guesses’ (or models) and combine them to get a better prediction.
Ensemble Methods in AI and Machine Learning are techniques used to create multiple models from a single training dataset, then combining their predictions or decisions to obtain a final prediction. These methods provide two primary advantages: improving performance and reducing generalization error.
Tweaking and training a single model can be challenging since it might overfit or underfit the data. With Ensemble Methods, we take a different approach - instead of relying on one model, we create several models (the ensemble), each making its decision.
Majorly, there are two categories for ensemble methods - Bagging and Boosting. Bagging involves creating multiple subsets of the original dataset through resampling and then training a model on each subset. Voting is carried out for predicting final output. A popular bagging algorithm is Random Forest, which constructs several decision trees to predict the output.
Boosting, on the other hand, refers to any Ensemble Method that can convert weak models to strong models. Algorithms train models sequentially. Each new model gradually corrects the errors made by the previous models. AdaBoost (Adaptive Boosting) and Gradient Boosting are examples of boosting algorithms.
Exploring further, Stacking, or Stacked Generalization, integrates different kinds of models. This technique involves training several different models then combining them by training a meta-model that makes the final prediction based on the individual models’ outputs.
A general idea behind ensemble methods is to exploit the independence between the base models since error can be reduced dramatically by averaging. It’s crucial to remember that ensemble methods require careful design because model diversity and the method of combining decisions greatly impact final performance.