Data-Free On-Policy Distillation: How Far Can We Go Without External Data?
Organizations: Foundation Model Research Center, Institute of Automation, Chinese Academy of Sciences · School of Artificial Intelligence, University of Chinese Academy of Sciences · Foundation Model Department, Tencent · National University of Singapore ·
Abstract
On-policy distillation (OPD) is increasingly applied to frontier foundation model post-training. Prior work in this area has largely focused on algorithmic advances, yet it remains unclear how much OPD depends on its training questions and, in particular, how far this dependence can be reduced. Across two representative single-teacher OPD settings, we find that training on 8 real prompts yields performance comparable to training on 17k problems, while datasets differing substantially in measured difficulty and initial distillation gap yield similar outcomes. Our analyses suggest two complementary explanations: repeated sampling could allow even a few prompts to expose substantial teacher supervision, while OPD transfers generalizable reasoning capabilities beyond dataset-specific knowledge. Building on these observations, we next propose a data-free on-policy distillation (DF-OPD) setting to investigate whether the system can supply the training questions itself, eliminating the need for external data. With 64 self-generated questions obtained without seed examples, DF-OPD yields performance comparable to full-data OPD in both single-teacher settings. This finding also holds in multi-teacher OPD: across mathematics, code, and instruction following, 1k generated questions achieve performance comparable to training on approximately 7k real post-training examples. We further explore whether OPD can operate even without explicit training questions. The experiments show that this is effective only in limited cases, where the student unexpectedly generates and answers its own questions, thereby reducing the process to an implicit form of DF-OPD. Together, these findings invite a reassessment of the role of training data in on-policy distillation. Code is available at https://github.com/Ryuki661/DF-OPD
Figures & tables
| Input / reference | Questions | Math | Code | IF | Overall | Recovery |
|---|---|---|---|---|---|---|
| Initial student | — | 15.83 | 15.77 | 41.01 | 24.21 | — |
| Routed teachers | — | 23.02 | 22.52 | 48.73 | 31.42 | 100% |
| Real post-training data | 7,458 | 23.02 | 21.71 | 48.80 | 31.18 | 96.6% |
| Self-generated | 8 | 23.44 | 19.64 | 45.92 | 29.66 | 75.6% |
| Self-generated | 64 | 22.60 | 20.87 | 47.51 | 30.33 | 84.8% |
| Self-generated | 256 | 23.54 | 20.99 | 47.86 | 30.80 | 91.3% |
Appendix figures & tables22 assets
Supplementary material from the paper’s appendix.
Appendix
| Setting | Student | Teacher | Relationship |
|---|---|---|---|
| RL-tuned teacher | DeepSeek-R1-Distill-Qwen-1.5B | JustRL-DeepSeek-1.5B | RL-tuned from the student |
| Larger teacher | Qwen3-1.7B | Qwen3-30B-A3B-Instruct-2507 | Different-scale models from the Qwen3 family |
| MOPD: math | SmolLM3-3B-MixSFT | SmolLM3-3B-RL-Math | Math-specific RL from MixSFT |
| MOPD: code | SmolLM3-3B-MixSFT | SmolLM3-3B-RL-Code | Code-specific RL from MixSFT |
| MOPD: instruction following | SmolLM3-3B-MixSFT | SmolLM3-3B-RL-IF | Instruction-following RL from MixSFT |
| Configuration | Single teacher | Multiple teachers |
|---|---|---|
| Questions per update | 64 | 64 |
| Student support size | 16 | 128 |
| Policy passes per rollout batch | 1 | 1 |
| Optimizer | AdamW | AdamW |
| Learning rate | ||
| AdamW | 0.9, 0.999 | 0.9, 0.999 |
| Configuration | Single-teacher math | MOPD math | MOPD code | MOPD IF |
|---|---|---|---|---|
| Responses per problem | 4 | 16 | 5 | 1 |
| Sampling temperature | 0.7 | 0.6 | 0.6 | 0.6 |
| Top- | 0.95 | 0.95 | 0.95 | 0.95 |
| Response limit (tokens) | 16,384 | 32,768 | 32,768 | 32,768 |
| Domain | Topics |
|---|---|
| Mathematics | algebra; geometry; number theory; combinatorics; probability; statistics; calculus; precalculus; trigonometry; logic puzzles; sequences and series; inequalities; functional equations; complex numbers; polynomials; graph theory |
| Code | dynamic programming; greedy algorithms; graph traversal; shortest paths; string processing; binary search; sorting and ordering; data structures; number theory; combinatorics and counting; simulation; two pointers; prefix sums; recursion and backtracking; intervals and scheduling; matrix and grid problems |
| Instruction following | response length in words; number of sentences; number of paragraphs; required keywords; forbidden words; starting and ending phrases; letter casing; JSON or structured output; bullet-point formatting; title or heading requirements; placeholder tokens; repeating the prompt; language of the response; punctuation restrictions; numbered list requirements; section markers |
| Teacher | Generation requests | Generation seeds | Final questions |
|---|---|---|---|
| RL-tuned teacher | 1,024 | 42 | 3,822 |
| Larger teacher | 1,024 | 42 | 3,930 |
| MOPD mathematics teacher | 1,024 | 42 | 2,971 |
| MOPD code teacher | 1,024 | 42 | 2,949 |
| MOPD instruction-following teacher | 1,024 | 42 | 3,082 |
| Topic | Question text |
|---|---|
| number theory | Find all prime numbers such that divides . |
| complex numbers | Let be a complex number satisfying . Find . |
| combinatorics | In how many ways can 8 people be seated around a circular table such that Alice and Bob cannot sit next to each other? |
| geometry | In a right-angled triangle with right angle at , the incircle touches at and at . The tangent from to the incircle meets at . If , , find the length of . |
| calculus | A 10-foot ladder is leaning against a vertical wall. The base of the ladder is being pushed away from the wall at a rate of 2 feet per second. When the base is 6 feet away from the wall, how fast is the top of the ladder sliding downward? |
| Topic | Question text |
|---|---|
| geometry | A regular dodecagon (12-sided polygon) is inscribed in a circle of radius 1. Let be a point on the circumference such that the sum of the squares of the distances from to each of the 12 vertices of the dodecagon is minimized. What is the minimum value of this sum? |
| trigonometry | In triangle , let , and let be a point on side such that bisects . Suppose and . If , find the exact value of using trigonometric identities and the Angle Bisector Theorem. |
| combinatorics | A group of 10 mathematicians is attending a conference. Each day, they form a circle to discuss a problem, and no two people can sit next to each other more than once during the conference. What is the maximum number of days the conference can last such that this condition is satisfied? |
| graph theory | Let be a simple, undirected graph with 12 vertices and 30 edges. Suppose that has no cycles of length 3 or 4 (i.e., girth at least 5). What is the maximum possible number of vertices of degree 5 or more in ? |
| precalculus | Let and . Find all real values of such that , and determine the sum of all such values. |
| Topic | Question text |
|---|---|
| number theory | What is the least positive integer for which the equation holds true? |
| functional equations | Find the function such that for all real numbers satisfying , we have . |
| calculus | A function satisfies the differential equation with initial conditions and . Let be the inverse function of . Find the value of . |
| sequences and series | What is the smallest positive integer such that the sum of the first consecutive positive integers is divisible by 17? |
| probability | What is the probability that a randomly selected positive integer less than or equal to 1000 has a remainder of 3 when divided by 11? |
| Topic | Question text |
|---|---|
| sorting and ordering | Problem Statement: Lexicographical Ordering of Strings Input Format: - The first line contains a single integer N ( ), denoting the number of strings to sort. - The following N lines each contain a string consisting of lowercase English letters only. No string will be empty and no character will appear more than once in a string. Output Format: - Print N space-separated strings in lexicographical order. Each string must be printed exactly as it appears in the input, and you may not modify the order of strings within the input as long as it matches the sorted order. Constraints: - Time Limit: 5 seconds - Memory Limit: 256 MB - Judge Logos: Standard |
| combinatorics and counting | Problem Statement Alice, Bob, and Carol are playing a game using a set of marbles. They want to divide the marbles into three non-empty groups such that the product of the number of marbles in each group is maximized. The constraint is that the number of marbles in each group must be a positive integer, and no two groups can have the same number of marbles. Determine the number of distinct ways to partition the marbles into three such groups. Input Format The first line contains a single integer , the number of test cases. Each subsequent line contains a single integer , representing the total number of marbles. Output Format For each test case, output a single integer representing the number of distinct ways to partition the marbles into three non-empty groups with distinct sizes. Constraints - - - The total number of marbles across all test cases does not exceed 1000. |
| graph traversal | Problem Statement: Longest Path in a Tree Input Format: - The first line contains two integers, and , representing the number of nodes and edges in the tree, respectively. - The subsequent lines describe the edges of the tree. Each line contains two integers, and , indicating an undirected edge between nodes and . Output Format: - Print a single integer, which is the length of the longest path (also known as the diameter) in the tree. The path should consist of exactly two distinct nodes, and the longest path must not include any cycles. Constraints: - - - Nodes are numbered from to . |
| data structures | Problem Statement: Weighted Path Reconstruction Input Format: - The first line contains two integers, and , representing the number of nodes and edges in the directed weighted graph, respectively. - The next lines describe the edges. Each line consists of three integers: , , and , indicating a directed edge from node to node with weight . Output Format: - Print integers, where the ith integer represents the minimum possible sum of weights of a path from node 1 to node . Constraints: - - - - - The graph can contain cycles and self-loops. |
| greedy algorithms | Problem Statement: Maximum Weight Connected Components Input Format: - The first line contains two integers, and , representing the number of nodes and edges in the graph, respectively. - The next lines each contain three integers, , , and , denoting an undirected edge between nodes and with a weight . Output Format: - A single integer, representing the maximum sum of weights of the connected components of the graph. If there are multiple components with the maximum sum, output the maximum sum. Constraints: - - - - - All edges are distinct pairs ( ). - There are no self-loops ( u == v ). - The graph is undirected, meaning if there is an edge between and , there is also an edge between and . |
| Topic | Question text |
|---|---|
| response length in words | Please follow these instructions in your response: - 150-200 words long. - Include exactly three paragraphs. - End with the word “Answer”. Write a brief description of a cozy reading nook you would love to have in your home. I need help imagining a perfect reading spot. |
| number of paragraphs | Please follow these instructions in your response: - The answer must consist of exactly three paragraphs. - Each paragraph must begin with the word “Step ”. - The response must not contain any numbers other than those that are inherently part of the English language. Write a short story that explores a hidden library where forgotten memories are stored. Please provide the story. |
| starting and ending phrases | Please follow these instructions in your response: - 1. The response must begin with the phrase “Begin with the stars.” - 2. The response must end with the phrase “and the moon.” - 3. The response must include the exact word “quill” at least once. - 4. The response must be exactly 50 words in length. Request: Write a short story that blends astronomy with a creative writing tool. |
| placeholder tokens | Please follow these instructions in your response: - Use exactly three placeholder tokens: [[TEMP]] , [[LOC]] , and [[DATE]] . - Replace each placeholder token with a suitable word or phrase that fits the context. - Ensure the total length of the response is between 20 and 40 words. - Do not include any additional placeholder tokens. Write a short paragraph using the placeholders above, describing a future travel adventure. |
| title or heading requirements | Please follow these instructions in your response: - 1. Write a title or heading for the response that matches the given keyword “Cosmic”. - 2. Include exactly three paragraphs in the answer. - 3. Use bold and italics formatting exactly twice each, within the same paragraph. - 4. Keep the response under 60 words. Describe, in your own words, how the term “Cosmic” might relate to a vast, interconnected network of ideas and data. Provide a clear, concise example of how this concept could be applied in a modern digital environment. |
| Setting | Training questions | With topic | Without topic | |
| RL-tuned teacher | 8 | 54.84 | 56.34 | |
| RL-tuned teacher | 64 | 56.61 | 56.63 | |
| RL-tuned teacher | 1k | 56.38 | 56.18 | |
| Larger teacher | 8 | 49.46 | 48.86 | |
| Larger teacher | 64 | 49.16 | 49.45 | |
| Larger teacher | 1k | 49.12 | 48.97 |
| Setting | Student | Domains | Sampled responses | Self-QA responses | Self-QA rate |
|---|---|---|---|---|---|
| RL-tuned teacher | DeepSeek-R1-Distill-Qwen-1.5B | Mathematics | 1,024 | 635 | 62.0% |
| Larger teacher | Qwen3-1.7B | Mathematics | 1,024 | 1 | 0.1% |
| MOPD | SmolLM3-3B-MixSFT | Mathematics, code, and instruction following | 1,024 | 121 | 11.8% |
| Case | Response text |
|---|---|
| 1 | Alright, so I need to find the vertical and horizontal asymptotes for the function . […] The discriminant . Since the discriminant is negative, this quadratic doesn’t factor over the real numbers. […] In this case, the numerator is degree 1 and the denominator is degree 2. So the degrees are different, with the numerator being less. Therefore, the horizontal asymptote should be . […] Final Answer The function has a horizontal asymptote at and no vertical asymptotes. |
| 2 | Alright, so I’ve got this problem here: “Given the function , find the equation of the tangent line at the point where .” […] So . Okay, so the point is . […] So . […] Therefore, the slope . […] Final Answer The equation of the tangent line is . |
| 3 | Alright, so I’m trying to find the integral of with respect to . Hmm, okay. I remember from my calculus class that integration by parts is useful for integrals involving trigonometric functions or functions that have an inverse. […] So, if I let , then would be… Hmm, what’s the derivative of ? I think it’s . […] Okay, so that simplifies to minus the integral of . […] Final Answer The integral of with respect to is . |
| 4 | Alright, so I have this equation to solve: 2 sin theta plus 6 equals zero . I’m a bit confused about where to start. […] That would give me 2 sin theta = . Then, maybe I can divide both sides by 2 to get sin theta by itself. So, sin theta would equal . […] Hold on, so if sin theta equals , which isn’t possible because sine can’t be outside that range. So does that mean there’s no solution? […] Final Answer The equation has no solution, so the solution set is . |
| 5 | Alright, I need to figure out how many different three-digit numbers can be formed using the digits 1, 2, 3, 4, 5, 6, 7, 8, and 9 without repeating any digits . I remember something about permutations and combinations, but I’m not completely sure. […] For the first digit (hundreds place), we have 9 options (digits 1-9). Once we’ve chosen the hundreds digit, we have 8 options left for the tens place. Then, after choosing hundreds and tens, we have 7 options left for the units place. […] Final Answer The number of different three-digit numbers is . |
| Case | Response text |
|---|---|
| 1 | Sure! Please provide the specific question or topic you’d like me to help with, and I’ll do my best to assist you. |
| 2 | I’m sorry, but I can’t assist with that request. Please provide a clear question or topic you’d like me to help with. |
| 3 | It seems like you provided a query, but there’s no content in the message. Could you please provide a specific question or topic you’d like me to help with? I’ll do my best to assist you! |
| 4 | I’m here to help! Could you please clarify what you need assistance with? For example, are you looking for help with a specific task, question, or need guidance on something? |
| 5 | Sure! Please provide the question you’d like me to answer. |
On-Policy Distillation
On-policy distillation trains a model on its own outputs using teacher guidance, aligning supervision with the states it encounters at deployment.
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