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REVIEW 4 major objections 6 minor 1 cited by

DPO-Shift: Shifting the Distribution of Direct Preference Optimization

T0 review · 4 major / 6 minor · reviewed 2026-08-08 · deepseek-v4-flash

Pith's one-line read DPO-Shift adds a tunable factor $f(\lambda)$ to the rejected term of the DPO loss and proves this converts likelihood displacement into a controlled trade-off: chosen-probability gains at the price of a smaller reward margin.

desk verdict A one-line DPO variant with solid empirical ablations but a broken proof and an overstated abstract; the trade-off is real, the theory as stated is not. read the letter →

arxiv 2502.07599 v2 pith:43HVHJB2 submitted 2025-02-11 cs.CL

classification cs.CL
keywords DirectPreferenceOptimizationlikelihooddisplacementalignmentBradley-Terrymodelrewardmargintunableparameterf(λ)winrateevaluationLLM
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

Direct Preference Optimization (DPO) is known to lower the probability the model assigns to chosen responses during training—a failure called likelihood displacement. This paper claims that multiplying the rejected response's log-ratio inside DPO's Bradley-Terry objective by a parameter function $f(\lambda)$ between 0 and 1 makes the chosen probability shift upward in a controllable way. The theoretical centerpiece is a one-step gap analysis showing that the change in chosen probability is $(1-f(\lambda))u_1$ and the change in the smoothed reward margin is $(1-f(\lambda))u_2$, where the measured signs $u_1>0$, $u_2<0$ imply a fundamental trade-off governed entirely by $f(\lambda)$. Experiments on Llama 3-8B and Qwen 2-7B across UltraFeedback and Capybara confirm that $f(\lambda)$ close to 1 (e.g., 0.95) lifts chosen probabilities while keeping reward margins nearly unchanged, and a designed win-rate evaluation has DPO-Shift beating DPO. A careful reader would care because the method is as simple as DPO, needs no dataset changes, and turns a known pathological behavior into a tunable dial.

What carries the argument

The load-bearing object is the modified Bradley-Terry loss $L_{\mathrm{DPO-Shift}}(\pi)=-\mathbb{E}[\log \sigma(\beta \log \frac{\pi_\theta(y_w|x)}{\pi_{\mathrm{ref}}(y_w|x)} - f(\lambda) \beta \log \frac{\pi_\theta(y_l|x)}{\pi_{\mathrm{ref}}(y_l|x)})]$, which inserts the parameter function $0<f(\lambda)<1$ as a multiplier on the rejected response's reward. The analysis proceeds by comparing one gradient step of this objective against one step of DPO: the gap in chosen log-probability and the gap in the smoothed reward-margin indicator factor as $(1-f(\lambda))u_1$ and $(1-f(\lambda))u_2$, with $u_1$ and $u_2$ defined as expectations of gradient inner products $\nabla_\theta \log \pi_\theta(y_l|x)^\top \nabla_\theta \log \pi_\theta(y_w|x)$ and related terms. Because the empirically measured signs are $u_1>0$ and $u_2<0$ on the SFTed Llama 3-8B / UltraFeedback configuration, the factor $(1-f(\lambda))>0$ directly yields the paper's core conclusion: an improvement in chosen probability that costs reward margin, with the size of both effects set by $f(\lambda)$.

What would settle it

Compute $u_1$ and $u_2$ on a different model family and preference dataset—say a Pythia-style checkpoint with the HH-RLHF dataset—at several training checkpoints; if any setting yields $u_1 \le 0$ or $u_2 \ge 0$, the paper's guarantee that $f(\lambda)<1$ improves chosen probability while reducing reward margin fails for that setting, and the recommended $f(\lambda)=0.95$ would need to be revisited.

Watch

Extended reading notes

Core claim

On its own terms, the paper establishes that the likelihood displacement of DPO can be mitigated by a one-line change to the loss: replace the DPO objective's rejected log-ratio with $f(\lambda)\log(\pi_\theta(y_l|x)/\pi_{\mathrm{ref}}(y_l|x))$, keeping $0<f(\lambda)<1$. Theorem 2.1 shows that after a single gradient step, the gap between DPO-Shift and DPO in chosen log-probability is exactly $(1-f(\lambda))u_1$, and the gap in the smoothed reward-margin indicator is $(1-f(\lambda))u_2$, where $u_1$ and $u_2$ are expectations over inner products of the chosen and rejected gradient log-probabilities. Measured on an SFTed Llama 3-8B with UltraFeedback, $u_1>0$ and $u_2<0$, so every $f(\lambda)<1$ improves the chosen probability at the expense of the reward margin. The paper further shows the trade-off magnitude scales with $1-f(\lambda)$: values close to 1 give near-DPO reward margins with a visible chosen-probability gain, while small values push chosen probability up but reduce reward accuracy and can overfit to chosen responses. The authors conclude the method mitigates likelihood displacement, is controlled by a scalar schedule that can be fixed or varied linearly over training, and outperforms DPO in downstream win-rate comparisons and perplexity.

Load-bearing premise

The conclusion that any $f(\lambda)<1$ improves the chosen probability rests on the measured sign pattern $u_1>0$ and $u_2<0$, which was obtained on a single model (SFTed Llama 3-8B) and a single dataset (UltraFeedback test set); if that sign pattern is not generic across models, datasets, and training stages, the recommended choice of $f(\lambda)<1$ could reduce chosen probability instead of improving it.

Editorial extensions

If this is right

  • With $f(\lambda)$ close to 1 (e.g., 0.95–0.99), DPO-Shift raises the chosen probability relative to DPO while keeping the reward margin and reward accuracy nearly unchanged, directly mitigating likelihood displacement.
  • Smaller $f(\lambda)$ increases the chosen probability further but progressively reduces the reward margin and reward accuracy; the paper observes that very small values can overfit to chosen responses and degrade preference alignment.
  • The trade-off is explicitly quantified by $(1-f(\lambda))u_1$ and $(1-f(\lambda))u_2$, so practitioners can choose $f(\lambda)$—or a linear schedule over training—to hit a desired balance between likelihood and margin.
  • On downstream evaluation, DPO-Shift beats DPO in a designed win-rate comparison (e.g., 72.15% vs 27.85% with linear_decrease $\lambda_{min}=0.95$ on Llama 3-8B / UltraFeedback) and produces lower perplexity on chosen responses (4.475 vs 18.996).
  • The modification requires no dataset filtering, no reference-model retraining, and no extra training stages; it is a drop-in change to the DPO loss.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The sign of $u_1$ should track the semantic similarity of chosen/rejected pairs: on datasets with mostly dissimilar pairs, $u_1<0$ may hold, and the paper's own analysis implies $f(\lambda)>1$ could then improve both chosen probability and reward margin simultaneously—a regime worth testing systematically rather than writing off as a crash risk.
  • A per-sample adaptive choice of $f(\lambda_i)$, assigned according to the sign of $u^i_1$ for each training pair, is the natural next step the authors leave as future work; one could test it by computing $u^i_1$ on the training set and applying $f(\lambda_i)<1$ where $u^i_1>0$ and $f(\lambda_i)>1$ where $u^i_1<0$.
  • The sign-pattern measurement is the paper's empirical linchpin, so independently reproducing $u_1>0$, $u_2<0$ across architectures and preference datasets would either widen or shrink the domain where the recommended $f(\lambda)<1$ is safe.
  • Because likelihood displacement is also addressed by data filtering approaches, DPO-Shift's soft weighting of the rejected term may compound with filtering—e.g., DPO-Shift on a filtered DPO-Positive-style dataset might recover margin loss while keeping chosen-probability gains.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

4 major / 6 minor

Summary. The paper proposes DPO-Shift, a modification of the DPO objective in which the rejected-response log-ratio term is multiplied by a function f(λ)∈(0,1). The central theoretical claim (Theorem 2.1, contribution C.2) is that after one gradient step the gap in chosen log-probability and in a smoothed reward-margin indicator between DPO-Shift and DPO factorizes as (1−f(λ))u1 and (1−f(λ))u2; combined with empirically measured signs u1>0 and u2<0, this is used to conclude that f(λ)<1 improves chosen probability at the cost of a reduced reward margin. The paper validates the predicted trade-off with ablations on Llama 3-8B and Qwen 2-7B over UltraFeedback and Capybara, and reports win-rate comparisons against DPO and other preference optimization methods.

Significance. If the theoretical claim were established, DPO-Shift would be a simple and practically useful remedy for likelihood displacement, a well-documented failure mode of DPO. The paper's strengths are its simple formulation, the released code, and the unusually thorough ablation over f(λ) values and multiple model/dataset combinations; the downstream comparison against SimPO, KTO, and IPO using their released checkpoints is also informative. However, the advertised 'theoretically grounded' guarantee is the main added value over the empirical observation, and the proof of Theorem 2.1 does not support the theorem as stated. The empirical sign pattern used to draw the main conclusion is measured on a single model/dataset pair, and the win-rate evaluation is partly circular, so the strongest claims in the paper are not yet supported.

major comments (4)
  1. [Theorem 2.1 / Appendix B] The theorem as stated is not a consequence of the proof in Appendix B. Using the proof's own update θ_{t+1}=θ_t+η(c1∇logπθ(yw|x)−c2∇logπθ(yl|x)), the one-step difference in ω1 between DPO-Shift and DPO is ηE[(c1^f−c1^0)||∇logπθ(yw|x)||² − (f c1^f−c1^0)∇logπθ(yl|x)^T∇logπθ(yw|x)], where the superscripts denote f(λ) and f=1. The proof drops the first term and thereby obtains g1=η(c1−c2)∇logπ(yl)^T∇logπ(yw); this is only legitimate when f≈1, not for all 0<f(λ)<1 as the theorem states. In addition, the theorem's g1 omits the factor η present in the proof, and the theorem's u2 in Eq. (9) omits the c(θ) factor that the proof's g2 expression contains. Finally, c(θ) in the theorem uses γ while the proof's c1 uses β, and γ is never assigned a value in the main text; the proof's remark 'use β → +∞' is not a derivation. The theorem therefore needs either a corrected statement with explicit f≈1, η, and constant factors, or a complete derivation under its stated hypotheses.
  2. [Section 2.2] The sign conclusion u1>0 and u2<0 is empirical, measured on one SFTed Llama 3-8B model on the UltraFeedback test set, and is not a consequence of the theorem. The manuscript does not verify the sign pattern at initialization for Qwen 2-7B, Capybara, or later training stages, so the recommendation f(λ)<1 is not established as generic. Moreover, the main text and Appendix B contradict each other: Section 2.2 reports 81.7% of the u_i^2 values as negative, while Appendix B reports 81.7% of the bracket term ∇logπ(yl)^T∇logπ(yw)−||∇logπ(yl)||² as positive; since the main text sets η1 to 1 when computing u2, these two statements cannot both be correct. This internal inconsistency weakens the empirical basis for the sign of u2.
  3. [Section 3.3 / Appendix A.2] The win-rate experiment is partly circular. The judge prompt instructs that 'the most important criterion is to select the response whose meaning is essentially closer to the reference answer,' and the reference answer is the chosen response whose likelihood DPO-Shift is specifically designed to increase. The evaluation metric therefore directly rewards the quantity DPO-Shift optimizes, so Table 1 does not provide an independent demonstration of better alignment quality. The perplexity comparison (4.475 vs 18.996) is similarly computed on the chosen responses of the test split, which again rewards the objective being shifted. Please re-run with a judge that does not have access to the reference answer, or report a judge based on general quality only.
  4. [Abstract / Contribution C.3] The abstract states that DPO-Shift demonstrates superiority on downstream tasks 'such as MT-Bench and a designed win rate experiment,' but no MT-Bench results appear anywhere in the main text or appendices. Either the MT-Bench results should be reported, or the abstract should be revised to mention only the win-rate experiment, which is the downstream evaluation actually presented.
minor comments (6)
  1. [Section 3.2] The sentence beginning 'A carefully chosen For example' is grammatically broken and should be rewritten.
  2. [Section 2.2] The notation u_i^1 and u_i^2 is hard to read; using a sample index as a subscript (e.g., u_1,i) would clarify the definitions.
  3. [Section 2.2] The phrase 'the first one is to fix it all along the optimization process, i.e., f(λ)=λ' is confusing because λ is never defined as a variable separate from the function argument; please define λ and the fixed strategy explicitly.
  4. [Appendix B] The phrase 'we abuse notation and use β → +∞ as hyper parameter' should be replaced with a precise statement about the smoothing factor γ; as written it suggests taking an infinite temperature limit that is not part of the training procedure.
  5. [Appendix B] The proof states that 81.7% of the computed bracket values 'turn out to be positive,' which is inconsistent with the main text's claim that 81.7% of the u_i^2 values are negative; please reconcile these numbers.
  6. [Table 1] Entries such as 'linear_increase 0.95' should specify whether 0.95 is λ_min or λ_max; currently the reader must infer the convention from the text.

Circularity Check

3 steps flagged · score 4.0 of 10

The central trade-off claim is not circularly derived: u1 and u2 are empirically measured, not defined to force the conclusion. However, the proof of Theorem 2.1 drops a nonzero term, and the downstream win-rate/perplexity evaluations are constructed around the exact chosen-likelihood quantity DPO-Shift is designed to increase.

  1. other [Appendix B, Eqs. (12)-(13) and Theorem 2.1 (Section 2.2)]
    "w1(θt+1) =w1(θt) +η (c1∇θ log πθt (yw|x) − c2∇θ log πθt (yl|x))⊤ (∇θ log πθt (yw|x)) (12) = w1(θt) +η (c1 ||∇θ log πθt (yw|x)||2 − c2∇θ log πθt (yl|x)⊤ ∇θ log πθt (yw|x)) (13) then g1(t + 1) =η(c1 − c2)∇θ log π (yl|x)⊤ ∇θ log π (yw|x)"

    For the DPO baseline f(λ)=1, the same expansion gives c1=c2=c, so subtracting the DPO update from Eq. (13) yields η[(c1−c)||∇ log πθ(yw)||² + (c−f c1)∇ log πθ(yl)ᵀ∇ log πθ(yw)], not the printed η(c1−c2)∇ log πθ(yl)ᵀ∇ log πθ(yw). The stated factorization g1=(1−f)u1 is obtained only after suppressing the nonzero η(c1−c)||∇ log πθ(yw)||² term and identifying c with c1, which is an f≈1 assumption. The theorem is claimed for all 0<f<1, so the proof does not establish the result; the 'without imposing additional assumptions' guarantee in C.2 is unsupported.

  2. self definitional [Section 3.3 (perplexity paragraph)]
    "Perplexity quantifies how well a probability model predicts a sample of data... The perplexity of DPO and DPO-Shift trained on UltraFeedback with fixed f (λ) = 0.95 is evaluated on the chosen responses from the test split of the UltraFeedback dataset. The results are 4.475 for DPO-Shift and 18.996 for DPO, further demonstrating the potential advantage of DPO-Shift."

    Perplexity of an autoregressive policy on the chosen responses is exp(−E log πθ(yw|x)/|yw|) up to a constant, so 'lower perplexity on chosen responses' is a monotone transform of the chosen log-probability that DPO-Shift is defined to increase (g1>0 under Theorem 2.1's claimed sign pattern). Reporting it as an additional downstream advantage is therefore a restatement of the optimized quantity, not an independent evaluation of the method.

1 more flagged steps
  1. other [Appendix A.2 (judge prompt) with Section 3.3 (win-rate experiment)]
    "The most important criterion is to select the response whose meaning is essentially closer to the reference answer."

    The reference answer is the chosen response yw of the preference dataset, and DPO-Shift's construction (Eq. (3)) plus the claimed g1>0 is specifically designed to raise log πθ(yw|x). Instructing the judge to prefer semantic closeness to the reference answer makes the win-rate comparison largely a measure of whether DPO-Shift has adopted the chosen-response distribution, which is the exact quantity that was deliberately shifted. The experiment is therefore partially self-confirming rather than an independent test of general quality.

full rationale

The core derivation is not circular by construction: u1 and u2 are measured empirically on the SFTed Llama 3-8B / UltraFeedback test set, and the claimed signs of g1 and g2 are not baked into the definitions of ω1 and ω2. However, the proof of Theorem 2.1 in Appendix B does not establish the stated factorization: from the paper's own Eq. (13), the one-step DPO-Shift vs DPO gap contains an extra η(c1−c)||∇ log πθ(yw)||² term that is silently dropped, and the remaining coefficient (c−f c1) is not (1−f)c1 unless c=c1. The theorem's 'no additional assumptions' statement is therefore unsupported; this is a proof gap rather than a circular definition, but it is the load-bearing step of claim C.2. Separately, the downstream evaluation is partially circular: perplexity on chosen responses is a monotone function of the chosen log-probability the method was built to increase, and the judge prompt makes closeness to the reference answer the primary win criterion, which rewards that same shifted distribution. The distributional and reward-margin experiments in Section 3.2 still provide independent, non-circular evidence for the empirical trade-off; the flaws are concentrated in the theoretical guarantee and in the framing of the downstream metrics. Overall circularity is moderate: the headline contribution has independent empirical content, but two of its advertised confirmations reduce to the design objective, and the claimed theorem is not derived as written.

Assumptions & free parameters 3 free parameters · 4 assumptions · 0 invented entities

Free parameters include the new f(λ) knob, the inherited β, and the ambiguous γ. The axioms are the standard BT assumption, the first-order approximation, and the unverified generalization of empirical sign patterns from a single setup. No new theoretical entities are introduced beyond the scalar f(λ).

free parameters (3)
  • f(λ) = ablation range 0.5 to 0.99
    The method's key hyperparameter; not fitted to data but swept in ablations. The paper recommends values close to 1 to balance the trade-off.
  • β (DPO temperature) = not specified in text; follows SimPO config
    Standard DPO hyperparameter inherited from prior work, not a new contribution.
  • γ (smoothing factor in Theorem 2.1) = unspecified; set to 1 in one empirical check
    Introduced in the theorem without a clear relation to β, making the theorem ambiguous. The paper uses γ=1 when computing u1 and u2 on the test set.
assumptions (4)
  • domain assumption Bradley-Terry model of preferences
    Used as the starting point for both DPO and DPO-Shift losses (Section 2.1).
  • domain assumption First-order Taylor expansion with small learning rate η
    The proof of Theorem 2.1 ignores second-order terms, requiring small η; the paper does not quantify this.
  • domain assumption Semantic similarity between chosen and rejected responses in preference datasets
    Used to argue u1>0 and u2<0 (Section 2.2). This is hypothesized from examples, not proven.
  • ad hoc to paper The empirical sign pattern u1>0, u2<0 computed on one SFTed model and dataset generalizes
    The theory's conclusions depend on these signs, which are only measured on Llama 3-8B SFT on the UltraFeedback test set.

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Cite this review

Pith. "Pith review of DPO-Shift: Shifting the Distribution of Direct Preference Optimization." pith.science (2026). https://pith.science/paper/43HVHJB2

@misc{pith2026250207599,
  author       = {Pith},
  title        = {Pith review of: DPO-Shift: Shifting the Distribution of Direct Preference Optimization},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/43HVHJB2}},
  note         = {Machine review of arXiv:2502.07599}
}
read the original abstract

Direct Preference Optimization (DPO) and its variants have become increasingly popular for aligning language models with human preferences. These methods aim to teach models to better distinguish between chosen (or preferred) and rejected (or dispreferred) responses. However, prior research has identified that the probability of chosen responses often decreases during training, and this phenomenon is known as likelihood displacement. To tackle this challenge, in this work we introduce DPO-Shift to controllably shift the distribution of the chosen probability. Then, we show that DPO-Shift exhibits a fundamental trade-off between improving the chosen probability and sacrificing the reward margin, as supported by both theoretical analysis and experimental validation. Furthermore, we demonstrate the superiority of DPO-Shift over DPO on downstream tasks such as MT-Bench and a designed win rate experiment. We believe this study shows that the likelihood displacement issue of DPO can be effectively mitigated with a simple, theoretically grounded solution. Our code is available at https://github.com/Meaquadddd/DPO-Shift.

Figures

Figures reproduced from arXiv: 2502.07599 by the authors.

Figure 1
Figure 1. Comparison of log probabilities and reward margins between DPO and DPO- [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Distribution for log πθ(yw|x), log πθ(yl |x) (up) and reward margin as well as the mean on test set split of UltraFeedback for Llama 3-8B trained on UltraFeedback with fixed strategy. Only limited cases of f(λ) are listed. For a full ablation study, please refer to Appendix A.3. The ranges of the y-axis of all subfigures are the same. 0.5 0.6 0.7 0.8 0.9 1.0 lambda 0.70 0.72 0.74 Llama 3-8B trained on ultrafeedback … view at source ↗
Figure 3
Figure 3. Reward accuracy vs different f(λ) on the UltraFeedback test set for Llama 3-8B trained on UltraFeedback with fixed, where f(λ) is selected from 0.5 to 0.95. 1000 500 0 log p (yw x) 0.00000 0.00025 0.00050 0.00075 0.00100 0.00125 0.00150 0.00175 0.00200 Density DPO-shift DPO 2 1 0 1 2 3 r(x, yw) r(x, yL) 0.0 0.2 0.4 0.6 0.8 1.0 DPO mean=0.582 DPO-Shift mean=0.588 [PITH_FULL_IMAGE:figures/full_fig_p007_3.png] view at source ↗
Figures from the paper (19 more)
Figure 5
Figure 5. Figure 5: Comparison between fixed strategy with f(λ) = 0.75 and linear_decrease with λmin = 0.75 on the test set split of UltraFeedback for Llama 3-8B trained on UltraFeedback. Left: Distribution for log πθ(yw|x) and log πθ(yl |x). Right: Reward accuracy and distribution for re…
Figure 6
Figure 6. Figure 6: Distribution for log πθ(yw|x) and log πθ(yl |x) on test set split of UltraFeedback for Llama 3-8B trained on UltraFeedback, where DPO-Shift uses fixed strategy. The ranges of the y-axis of all subfigures are the same. r(x, yw) r(x, yL) SFTed model r(x, yw) r(x, yL) mea…
Figure 7
Figure 7. Figure 7: Distribution for reward margin and its mean on test set split of UltraFeedback for Llama [PITH_FULL_IMAGE:figures/full_fig_p016_7.png]
Figure 8
Figure 8. Figure 8: Distribution for log πθ(yw|x) and log πθ(yl |x) on test set split of Capybara for Llama 3-8B trained on Capybara, where DPO-Shift uses fixed strategy. The ranges of the y-axis of all subfigures are the same. r(x, yw) r(x, yL) SFTed model r(x, yw) r(x, yL) mean = 0.032 …
Figure 9
Figure 9. Figure 9: Distribution for reward margin and its mean on test set split of Capybara for Llama 3-8B [PITH_FULL_IMAGE:figures/full_fig_p017_9.png]
Figure 10
Figure 10. Figure 10: Distribution for log πθ(yw|x) and log πθ(yl |x) on test set split of UltraFeedback for Qwen 2-7B trained on UltraFeedback, where DPO-Shift uses fixed strategy. The ranges of the y-axis of all subfigures are the same. r(x, yw) r(x, yL) SFTed model r(x, yw) r(x, yL) mea…
Figure 11
Figure 11. Figure 11: Distribution for reward margin and its mean on test set split of UltraFeedback for Qwen [PITH_FULL_IMAGE:figures/full_fig_p018_11.png]
Figure 12
Figure 12. Figure 12: Distribution for log πθ(yw|x) and log πθ(yl |x) on test set split of Capybara for Qwen 2-7B trained on Capybara, where DPO-Shift uses fixed strategy. The ranges of the y-axis of all subfigures are the same. r(x, yw) r(x, yL) SFTed model r(x, yw) r(x, yL) mean = 0.008 …
Figure 13
Figure 13. Figure 13: Distribution for reward margin and its mean on test set split of Capybara for Qwen 2-7B [PITH_FULL_IMAGE:figures/full_fig_p019_13.png]
Figure 14
Figure 14. Figure 14: Distribution for log πθ(yw|x) and log πθ(yl |x) on test set split of Ultrafeedback for Llama 3-8B trained on UltraFeedback, where DPO-Shift uses linear_increase and linear_decrease strategies. The ranges of the y-axis of all subfigures are the same. r(x, yw) r(x, yL) …
Figure 15
Figure 15. Figure 15: Distribution for reward margin and its mean on test set split of Ultrafeedback for Llama [PITH_FULL_IMAGE:figures/full_fig_p020_15.png]
Figure 16
Figure 16. Figure 16: Distribution for log πθ(yw|x) and log πθ(yl |x) on test set split of Capybara for Llama 3-8B trained on Capybara, where DPO-Shift uses linear_increase and linear_decrease strate￾gies. The ranges of the y-axis of all subfigures are the same. r(x, yw) r(x, yL) SFTed mod…
Figure 17
Figure 17. Figure 17: Distribution for reward margin and its mean on test set split of Capybara for Llama 3-8B [PITH_FULL_IMAGE:figures/full_fig_p021_17.png]
Figure 18
Figure 18. Figure 18: Distribution for log πθ(yw|x) and log πθ(yl |x) on test set split of UltraFeedback for Qwen 2-7B trained on UltraFeedback, where DPO-Shift uses linear_increase and linear_decrease strategies. The ranges of the y-axis of all subfigures are the same. r(x, yw) r(x, yL) S…
Figure 19
Figure 19. Figure 19: Distribution for reward margin and its mean on test set split of UltraFeedback for Qwen [PITH_FULL_IMAGE:figures/full_fig_p022_19.png]
Figure 20
Figure 20. Figure 20: Distribution for log πθ(yw|x) and log πθ(yl |x) on test set split of Capybara for Qwen 2-7B trained on Capybara, where DPO-Shift uses linear_increase and linear_decrease strate￾gies. The ranges of the y-axis of all subfigures are the same. r(x, yw) r(x, yL) SFTed mode…
Figure 21
Figure 21. Figure 21: Distribution for reward margin and its mean on test set split of Capybara for Qwen 2-7B [PITH_FULL_IMAGE:figures/full_fig_p023_21.png]
Figure 22
Figure 22. Figure 22: Distribution for log πθ(yw|x) and log πθ(yl |x) on test set split of UltraFeedback for Llama 3-8B trained on UltraFeedback, where DPO-Shift uses fixed strategy. The ranges of the y-axis of all subfigures are the same. r(x, yw) r(x, yL) mean = 0.569 DPO-shift with f( )…
Figure 23
Figure 23. Figure 23: Distribution for reward margin and reward accuracy on test set split of UltraFeedback [PITH_FULL_IMAGE:figures/full_fig_p024_23.png]

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Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

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    cs.CV 2025-06 conditional novelty 4.0 of 10

    LeanPO improves Video-LLM alignment by using a reference-free average-likelihood reward, self-generated winning/losing pairs, and dynamic label smoothing, yielding gains on six video benchmarks.

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Pith tools

Reviewed August 8, 2026 · model on record in the stance chip above.