01 / THE IDEA

On-policy vs off-policy learning in practice.

On-policy and off-policy methods differ in whether the data used for learning comes from the policy being improved. On-policy learners (for example SARSA or policy-gradient methods) evaluate or improve the policy that generated experience. Off-policy learners (for example Q-learning or importance-sampling-based evaluation) learn about a target policy from data collected by another behaviour policy. Typical error cases include non-stationary rewards, insufficient coverage of the state-action space, and unstable value estimates under function approximation.

Real-world use case · Proposed extension

A proposed application is to compare learning stability when tuning controllers in simulation, for example checking whether offline logs allow reliable policy improvement before deploying changes to physical hardware. In such uses, keep a human operator in the loop for safety and final decisions.

02 / THE BUILD

How to build a on-policy vs off-policy learning project
step by step.

01

Define environment and metrics

Specify the state and action spaces, episodic termination rules, reward signal and metrics such as average episodic return, regret and variance across seeds.

02

Collect on- and off-policy data

Generate experience under different behaviour policies (e.g. exploratory vs greedy) and separate datasets for on-policy training and offline evaluation.

03

Implement baseline learners

Fit simple on-policy and off-policy algorithms (SARSA, Q-learning or REINFORCE vs DQN) and log reward curves and stability across seeds.

04

Evaluate and inspect failures

Compare average return, convergence speed and failure modes such as divergence, high variance or poor coverage of rare states.

03 / SOURCE SNAPSHOT

What the on-policy vs off-policy learning starter actually does.

The supplied starter simulates a 4-armed Bernoulli bandit using an epsilon-greedy online loop: it samples actions, observes binary rewards drawn from fixed true reward rates, updates incremental sample-average estimates and prints counts, estimates and total reward. It does not implement episodic environments, off-policy evaluation, or explicit on-policy/off-policy algorithm comparisons.

SOURCE EXCERPTPython
for step in range(1, 2001):
    if rng.random() < epsilon:
        action = rng.integers(len(true_reward_rates))
    else:
        action = int(np.argmax(estimated_values))

    reward = 1 if rng.random() < true_reward_rates[action] else 0
    action_counts[action] += 1
    total_reward += reward
    estimated_values[action] += (reward - estimated_values[action]) / action_counts[action]
Important limitation

The code runs a simple epsilon-greedy bandit update and does not implement any off-policy algorithm, episodic environment, policy-gradient method, or off-policy evaluation technique named by the project title.

04 / BEYOND THE CLASSROOM

Where a on-policy vs off-policy learning project could go next.

PROPOSED BUSINESS CONCEPT

On-policy vs Off-policy: a pilot experiment

Proposed extension: run comparable on-policy (SARSA or REINFORCE) and off-policy (Q-learning or DQN) learners on a Gymnasium environment such as CartPole, using seeded repeats and logging average return, regret and variance to compare stability.

WHO IT COULD SERVEStudents and engineers learning RL
FIRST MVPA reproducible experiment that trains SARSA and Q-learning on a simple Gym environment, plots average episodic return across seeds, and stores logs for offline evaluation.
KEY RISKModel instability or divergence under function approximation and unsafe actions if transferred to real hardware; maintain a human operator and safety constraints when moving beyond simulation.

This is a potential application pathway, not a delivered product. The supplied starter does not implement this service or validate it with real users.

05 / WHAT YOU TAKE AWAY

What a on-policy vs off-policy learning project puts on your resume.

  • Define a reinforcement-learning problem with state, action, reward and termination rules and select appropriate metrics such as average episodic return and regret.
  • Implement a reproducible baseline epsilon-greedy bandit learner and verify incremental value updates.
  • Design and run a controlled comparison between an on-policy algorithm (e.g. SARSA) and an off-policy algorithm (e.g. Q-learning) in simulation.
  • Inspect failure cases: poor coverage of state-action pairs, high variance across seeds, and divergence when using function approximation.
Want to build this with mentors and a lab?

Networkers Home runs this topic inside its AI Engineer Course, with placement support and hands-on labs.

AI Engineer Course
06 / QUESTIONS STUDENTS ASK

On-Policy vs Off-Policy Learning project FAQs.

Is this topic suitable for a final year project?
Yes — the comparison of on-policy and off-policy methods is a solid final year project topic that can scale from bandit experiments to episodic RL, showing theoretical and empirical results.
What should I learn or prepare before starting?
You should be comfortable with Python, NumPy, basics of probability, Markov decision processes, and Gymnasium; familiarity with SARSA, Q-learning and policy-gradient concepts helps accelerate progress.
How do I evaluate progress and how long will it take?
Start with bandit experiments then move to episodic environments; evaluate via learning curves, return statistics and policy stability. A minimal prototype takes a few weeks; deeper experiments with function approximation will take longer.