Random forest vs Gradient boosting

Difference Between Random forest vs Gradient boosting

Random forest vs gradient forest is defined as, the random forest is an ensemble learning method which is used to solve classification and regression problems, it has two steps in its first step it involves the bootstrapping technique for training and testing, and the second step involves decision trees for prediction purpose, whereas, gradient boosting is defined as the machine learning technique which is also used to solve regression and classification problems, it creates a model in a stepwise manner, it is derived by optimizing an objective function we can combine a group of a weak learning model to build a single strong learner.

Head to Head Comparison Between Random forest vs Gradient boosting (Infographics)

Below are the top differences between Random forest vs Gradient boosting:

 Key Differences

• Performance:

There are two differences to see the performance between random forest and the gradient boosting that is, the random forest can able to build each tree independently on the other hand gradient boosting can build one tree at a time so that the performance of the random forest is less as compared to the gradient boosting and another difference is random forest combines its result at the end of the process while gradient combines the result along the way of it.

• Bagging vs boosting:

The combining of decision trees is the main difference between random forest and gradient boosting, random forest has been built by using the bagging method, the bagging method is the method in which each decision tree is used in parallel and each decision tree in it can fit subsample which has been taken from the entire dataset, in case of classification result is determined by taking all the result of decision trees and for regression tasks, the overall result is calculated by taking the mean of all predictions, on the other hand, gradient boosting uses the boosting technique to build an ensemble model, to build a new strong tree the decision trees are connected in series in which decision tree is not fit into the entire dataset.

• Overfitting:

Overfitting is the critical issue in machine learning techniques, as we know in machine learning we use algorithms so that there is a risk of overfitting and that can be considered as a bottleneck in machine learning when any model fits the training data well then there may occur overfitting due to that our model can take some unnecessary details under the training data and so it fails to generalize to the entire data.

As we have seen above the random forest and gradient boosting both are ensemble learning models, the random forest uses several decision trees that are not critical or does not cause overfitting, if we add more trees in it then the accuracy of the model will decrease so we do not want to add more trees, hence there may occur computational reason but in the random forest, there is no risk of overfitting, whereas, in gradient boosting due to the number of trees may occur overfitting, in gradient the new tree has been added from remaining to the previous one so each addition may occur noise in training data so adding of many trees in gradient boosting will cause the overfitting.

• Bootstrapping:

Bootstrapping is the technique which is used in statistics it uses a sample of data to make predictive data each sample of data is called the bootstrap sample, in the random forest if we do not use bootstrapping technique then each decision tree fits into the dataset due to that many algorithms will be applied to the same dataset it does good in manner, as we are doing it repeatedly, as a result, it gives better performance, if we use same or different decision trees then the result we get will not very different as compared to the result we get by single decision tree hence bootstrapping plays an important role in creating different decision trees, whereas, gradient boosting does not uses the bootstrapping technique each decision tree in it fits into the remaining to the previous one, so it does not work well with which has different trees.

Comparison Table of Random Forest vs Gradient Boosting

S.N.	Random forest	Gradient boosting
1.	It can build each tree independently.	Whereas, it builds one tree at a time.
2.	The bagging method has been to build the random forest and it is used to construct good prediction/guess results.	Whereas, it is a very powerful technique that is used to build a guess model.
3.	The random forest has many decision trees so by using the bootstrapping method individual trees will try to create an uncorrelated forest of trees.	Using gradient boosting helps to create a human movement tracker model.
4.	The prediction model it gives is more accurate than any other individual tree.	On the other hand, it creates higher accurate results as compared to a single strong learning method.
5.	The results are combined at the end of the process.	Whereas, it combines results along the way.
6.	It gives less performance as compared to gradient boosting.	Where it gives better performance, but when we have a lot of noise then the performance of it is not good.
7.	Multi-class object detection and bioinformatics also gives better performance.	On the other hand, it gives a good performance when we have unbalanced data such as in real-time risk assessment.
8.	It uses decision trees for prediction/guess purposes.	But, it uses regression trees for prediction/guess purposes.
9.	It is easy to use.	As they involve many numbers of steps it is quite hard to use.
10.	A sample of training data has been over fitted and then over fit has been reduced by using simple averaging of the predictors.	Whereas it repeatedly trains trees or the remaining of the previous predictor.

Conclusion

In this article, we conclude that random forest and gradient boosting both have very efficient algorithms in which they use regression and classification for solving problems, and also overfitting does not occur in the random forest but occurs in gradient boosting algorithms due to the addition of several new trees.

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