How Random Forests Can Keep You From Decision Tree

Life cycle of a tree begins with a seed. Then seed grows and becomes a young plant. Young plant is tranformed to a tree in years. After then, trees convert their areas to forest. Giant forests all came from a single seed at first. So, rule based systems follow similar steps.

baobab-trees
Baobab trees, Okan Bayulgen

Data would be a seed in this lifecycle. Growing data becomes dataset and that would be a young plant. Decision tree algorithms transform datasets to rule based trees. Decision tree algorithm is applied to dataset and it becomes to a tree.

decision-tree
Decision tree

Herein, random forest is a new algorithm derived from decision trees. Instead of applying decision tree algorithm on all dataset, dataset would be seperated into subsets and same decision tree algorithm would be applied to these subsets. Decision would be made by the highest number of subset results.

random-forest
Random forest

Decision Tree is Good, but Random Forests are Better

So, why traditional decision tree algorithm evolved into random forests? Working on all dataset may cause to overfitting. In other words, it might cause memorizing instead of learning. In this case, you would have high accuracy on training set, but you would fail on newly instances.

What’s more, random forests work on multiple and small datasets. Increasing the dataset size would increase the learning time exponentially in decision tree. So, you can parallelize the learning procedure in random forest. In this way, learning time would last less than decision tree.

If decision tree algorithm were the wise / sage person of around you, then random forests would be multiple smart people. Wise one might know every domain but each smart person can be expert on different domains. Wise one would most probably respond the correct answer but you might not always have a opportunity to ask him. However, bringing smart people to gather would most probably be acceptable.

You might remember the Voltron cartoon series. That was a legendary cartoon in my childhood. Nowadays, Netflix reshoot it. To sum up, there are 5 different lion robots and they have ability to fight individually. These robots can also combine and become a giant robot called as Voltron. Every episode they try to fight individually but finally they need to combine and become Voltron to defeat the enemy. So, random forests are just like combining Voltron!

voltron
Voltron is a super robot combined from 5 different robots

Still, there is nothing new under the sun!

 

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