
Back Again to Monte Carlo
Last Updated on August 28, 2025 by Editorial Team
Author(s): Rem E
Originally published on Towards AI.
We will explore our second method for solving RL problems
We’re diving into our second method for solving RL problems: Monte Carlo (MC). You’ve already seen it in Implementing the Value Function the Monte Carlo Way (tutorial 5). We computed values but didn’t update the policy. Now we’ll do it properly, step by step: generate complete episodes, estimate returns, average them to get value estimates, and then use those estimates to improve the policy
This article introduces the Monte Carlo (MC) method for solving reinforcement learning (RL) problems, focusing on generating complete episodes and estimating returns to improve policies. It contrasts MC with Dynamic Programming (DP), highlighting how MC only requires experience from interactions, unlike DP, which demands full knowledge of the environment. The article details two methods within MC: Every-visit MC and First-visit MC, and emphasizes the importance of exploration versus exploitation through on-policy and off-policy methods. It concludes with a discussion about ε-greedy policies and their role in ensuring continuous exploration while gradually shifting towards optimal policies.
Read the full blog for free on Medium.
Join thousands of data leaders on the AI newsletter. Join over 80,000 subscribers and keep up to date with the latest developments in AI. From research to projects and ideas. If you are building an AI startup, an AI-related product, or a service, we invite you to consider becoming a sponsor.
Published via Towards AI
Take our 90+ lesson From Beginner to Advanced LLM Developer Certification: From choosing a project to deploying a working product this is the most comprehensive and practical LLM course out there!
Towards AI has published Building LLMs for Production—our 470+ page guide to mastering LLMs with practical projects and expert insights!

Discover Your Dream AI Career at Towards AI Jobs
Towards AI has built a jobs board tailored specifically to Machine Learning and Data Science Jobs and Skills. Our software searches for live AI jobs each hour, labels and categorises them and makes them easily searchable. Explore over 40,000 live jobs today with Towards AI Jobs!
Note: Content contains the views of the contributing authors and not Towards AI.