DICE: Decoupling Capability from Intervention Necessity in LLM Tutoring
Organizations: Department of Computer Science and Engineering State University of New York at Buffalo
Abstract
Fluent guidance is not the same as useful intervention. LLM tutors are typically trained to generate the next teacher utterance, implicitly assuming that every student turn warrants a response. However, our experiments indicate that this conflates tutoring capability (what to say) with intervention necessity (whether to say it). We introduce DICE, a framework that decouples intervention decisions from response generation by first selecting an explicit pedagogical action. To calibrate this action selection policy, we define Intervention Value (IV), a rollout-grounded counterfactual metric that compares each action against non-intervention. IV shows that many prescribed interventions provide little or no marginal benefit. We further introduce DICE-Bench, a multi-variant math tutoring benchmark with skill-preserving problem variants for session-level evaluation. Using IV-weighted and KL-regularized policy optimization, DICE learns to intervene selectively while preserving tutoring effectiveness. In simulated tutoring sessions, DICE reduces the over-intervention rate to near zero while guiding students to correct solutions in approximately 3-4 fewer turns on average than existing Socratic tutoring baselines.
Figures & tables
| Turn | Dialogue rollout |
|---|---|
| Problem: A 400-page manuscript is copied and bound 10 times. Printing costs \0.05$58%$ sales tax. What is the total cost including tax? | |
| S | |
| T | Over-intervention It seems you calculated the cost before tax. Try including the sales tax. |
| S | |
| T | You may have missed part of the total. First compute printing and binding, then apply tax. |
| S | Printing is , binding is . |
| Metric | Easy | Source | Hard | E S | S H |
|---|---|---|---|---|---|
| Steps | 2.23 | 3.09 | 3.63 | 95.9% | 86.8% |
| Operators | 1.96 | 3.27 | 4.49 | 88.9% | 79.9% |
| Equations | 2.33 | 2.93 | 4.80 | 87.5% | 92.6% |
| Numeric tokens | 7.00 | 10.71 | 14.19 | 94.3% | 83.2% |
| Question tokens | 29.38 | 47.18 | 47.76 | 97.4% | 60.8% |
| Provenance | dialogue | step | step |
|---|---|---|---|
| Decision points | 7,625 | 4,728 | 8,124 |
| Action distribution, all variants, | |||
| ( accept ) | 8,037 (39.2%) | ||
| ( arith. repair ) | 4,019 (19.6%) | ||
| ( handle_q ) | 3,888 (19.0%) | ||
| Method | All3 | Vars. | Turn | OInt | UAcc |
|---|---|---|---|---|---|
| Full | 0.564 | 2.324 | 11.940 | 0.028 | 0.000 |
| w/o Cost | 0.532 | 2.284 | 13.048 | 0.036 | 0.000 |
| w/o Guard | 0.552 | 2.300 | 11.720 | 0.026 | 0.032 |
| w/o Verifier | 0.520 | 2.240 | 10.850 | 0.020 | 0.291 |
| w/o All | 0.216 | 1.496 | 18.048 | 0.880 | 0.076 |
| Mode | Method | All-3 | Vars. | Turns | OverInt. | UnsafeAcc. | |||
|---|---|---|---|---|---|---|---|---|---|
| Soc. Tut. | StratL | 0.440 | 0.868 | 0.700 | 0.440 | 2.008 | 15.112 | 0.768 | 0.272 |
| Ft. MathDial | 0.080 | 0.516 | 0.284 | 0.080 | 0.880 | 19.164 | 0.904 | 0.008 | |
| Soc. Prompting | 0.216 | 0.772 | 0.508 | 0.216 | 1.496 | 18.048 | 0.880 | 0.076 | |
| SocraticLM | 0.376 | 0.844 | 0.644 | 0.376 | 1.864 | 14.884 | 0.420 | 0.400 | |
| DICE | MAP | 0.532 | 0.928 | 0.824 | 0.532 | 2.284 | 13.048 | 0.036 | 0.000 |
| Cost | 0.564 | 0.928 | 0.832 | 0.564 | 2.324 | 11.940 | 0.028 | 0.000 |
Appendix figures & tables13 assets
Supplementary material from the paper’s appendix.
Appendix
| Action | Problem and dialogue context | Diagnosis | Rationale |
|---|---|---|---|
| Accept and advance | Problem: John plants a plot of trees by trees. Each tree gives apples, and each apple sells for \0.53\times 4=12$ trees. | – Correct – On track – No issue | The student answers the current subgoal correctly and shows the needed reasoning, so no intervention is necessary. |
| Ask for justification | Problem: John plants a plot of trees by trees. Each tree gives apples, and each apple sells for \0.53+43\times 4=1212560$ ? | – Correct – On track – Weak justification | The answer is correct, but the student gives no reasoning, so the tutor should ask for justification rather than simply advance. |
| Arithmetic repair | Problem: John plants a plot of trees by trees. Each tree gives apples, and each apple sells for \0.53\times 4=12512\times 5=70$ apples in total. | – Incorrect – On track – Arithmetic error | The student selects the correct operation but miscomputes , so the tutor should repair the arithmetic rather than change the subgoal. |
| Action | Meaning |
|---|---|
| Accept and advance | The student has satisfied the current subgoal, so the tutor should acknowledge the response and move to the next step without adding extra scaffolding. |
| Arithmetic repair | The student is following the right reasoning path but makes a numerical or computation error; the tutor should correct or guide the calculation while preserving the current subgoal. |
| Conceptual hint | The student shows a misunderstanding of the underlying concept or operation; the tutor should provide a light conceptual cue without directly giving away the full solution. |
| Handle question | The student asks a clarification or meta-level question; the tutor should answer the question and then return the student to the relevant subgoal. |
| Ask for justification | The student’s answer may be correct or partially correct, but the reasoning is missing or weak; the tutor should prompt the student to explain or justify their step. |
| Refocus subgoal | The student skips the current subgoal, jumps ahead, or drifts from the intended trajectory; the tutor should redirect attention to the current step. |
| Model | Training setup | Act. Acc. | Act. F1 | OverInt. | F1 | F1 | F1 |
|---|---|---|---|---|---|---|---|
| Llama-3.1-8B Ins. | Pretrained | 3.42 | 3.32 | 38.42 | 2.26 | 4.05 | 3.43 |
| SFT ( DA ) | 74.54 | 57.64 | 5.82 | 60.07 | 43.50 | 60.61 | |
| SFT ( A ) | 76.78 | 61.83 | 4.64 | 64.51 | 40.02 | 68.10 | |
| IV calibrated SFT ( A ) | 84.65 | 71.43 | 2.79 | 74.54 | 49.75 | 79.67 | |
| Qwen-2.5-3B Ins. | Pretrained | 8.99 | 11.25 | 38.47 | 6.78 | 13.13 | 11.94 |
| SFT ( DA ) | 33.28 | 23.20 | 17.16 | 27.14 | 18.56 | 24.92 |
| Student Model | Prompting Setup | Overall Acc. | Acc. | Acc. | Acc. |
|---|---|---|---|---|---|
| Qwen-2.5-0.5B Ins. | Zero-shot | 10.25 | 19.90 | 7.70 | 3.15 |
| CoT | 10.92 | 20.75 | 9.15 | 2.85 | |
| CoT + Steps | 13.35 | 23.95 | 9.10 | 7.00 | |
| Qwen-2.5-1.5B Ins. | Zero-shot | 20.73 | 38.25 | 17.00 | 6.95 |
| CoT | 21.22 | 39.30 | 17.75 | 6.60 | |
| CoT + Steps | 24.38 | 43.20 | 18.70 | 11.25 |
| Rank | Mode | Teacher | HP | Acc. | Turns-S | Int./Prob. | OverInt. | FalseAcc. | Score |
|---|---|---|---|---|---|---|---|---|---|
| 1 | DICE-Cost | Qwen-2.5-7B | 0.865 | 1.617 | 0.885 | 0.000 | 0.277 | 0.682 | |
| 2 | DICE-Threshold | Qwen-2.5-7B | 0.851 | 1.595 | 1.068 | 0.034 | 0.297 | 0.632 | |
| 3 | DICE-Cost | Qwen-2.5-7B | 0.815 | 1.597 | 1.192 | 0.000 | 0.281 | 0.615 | |
| 4 | DICE-MAP | Qwen-2.5-7B | – | 0.836 | 1.746 | 1.027 | 0.007 | 0.349 | 0.606 |
| 5 | DICE-Cost | SocraticLM | 0.812 | 1.760 | 0.758 | 0.000 | 0.342 | 0.603 | |
| 6 | DICE-Cost | SocraticLM | 0.805 | 1.842 | 0.705 | 0.000 | 0.389 | 0.576 |
| Case | Tutor | Problem and dialogue rollout | Behavior |
|---|---|---|---|
| Over-intervention Problem : Mary earns \46$3006$24$ left. | SocraticLM | S: , so Mary cleaned homes. The leftover is 300-(46\times 6)=\86$8300-(46\times 6)=$84-$276=$1246$124300-$276=$246$24300-$276=$24$ . — Student gets confused and misguided, and teacher continues intervention | The baseline first accepts an incorrect remainder, then repeatedly intervenes even after the student reaches the correct answer. It continues intervening till set budget. |
| DICE | S: Mary could clean whole homes since , and have \18$300$46$300646\times 6=$276300-276=$24$ . T: Accept and advance That’s correct. | DICE applies one targeted arithmetic repair, then accepts once the student is on track. | |
| False acceptance Problem : A library bookcase held books. On Monday were borrowed; on Tuesday were returned; on Wednesday more were borrowed. How many books are on the shelf at the end of Wednesday? Answer : . | SocraticLM | S: . So there are books remaining. T: False acceptance That’s correct! You’ve successfully calculated the number of books left on the shelf at the end of Wednesday. Well done! S: Thank you for your encouragement! It’s great to see I was able to solve this problem correctly. T: Keep up the good work! | The baseline validates the wrong answer , reinforcing an incorrect trajectory instead of repairing the arithmetic. |
| DICE | S: . So there are books remaining. T: Arithmetic repair Let’s recheck the subtraction and addition step by step. You started with books. After Monday, were borrowed, so you did . Can you verify that calculation? S: . Then , and . T: Accept and advance That’s correct. | DICE detects the arithmetic error, repairs the intermediate step, and accepts only after the student reaches the correct answer. |
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