Is Peer Review Really in Decline? Analyzing Review Quality across Venues and Time
Organizations: Ubiquitous Knowledge Processing Lab (UKP Lab), Department of Computer Science, Technical University of Darmstadt and National Research Center for Applied Cybersecurity ATHENE · Department of Computer Science at Queens College, City University of New York (CUNY)
Abstract
Peer review is at the heart of modern science. As submission numbers rise and research communities grow, the decline in review quality is a popular narrative and a common concern. Yet, is it true? Review quality is difficult to measure, and the ongoing evolution of reviewing practices makes it hard to compare reviews across venues and time. To address this, we introduce a new framework for evidence-based comparative study of review quality and apply it to major AI and machine learning conferences: ICLR, NeurIPS and *ACL. We document the diversity of review formats and introduce a new approach to review standardization. We propose a multi-dimensional schema for quantifying review quality as utility to editors and authors, coupled with both LLM-based and lightweight measurements. We study the relationships between measurements of review quality, and its evolution over time. Contradicting the popular narrative, our cross-temporal analysis reveals no consistent decline in median review quality across venues and years. We propose alternative explanations, and outline recommendations to facilitate future empirical studies of review quality.
Figures & tables
| Measurement | Domain | Range |
| Substantiveness | ||
| ITX: Core items count | ||
| LEN: Review length | ||
| Actionability | ||
| ACT: Actionability score | ||
| REQ: Number of requests | ||
Appendix figures & tables48 assets
Supplementary material from the paper’s appendix.
Appendix
| Accept | Reject | Total | |
| ICLR-2018 | 1.3k | 1.5k | 2.8k |
| ICLR-2019 | 1.5k | 2.8k | 4.3k |
| ICLR-2020 | 2.1k | 4.6k | 6.7k |
| ICLR-2021 | 3.3k | 6.7k | 10.0k |
| ICLR-2022 | 4.2k | 6.0k | 10.2k |
| ICLR-2023 | 6.0k | 8.4k | 14.3k |
| Campaign | Textual | Ordinal | Nominal | Cardinal |
| ICLR-2018 | Review | Rating, Confidence | - | - |
| ICLR-2019 | Review | Rating, Confidence | - | - |
| ICLR-2020 | Review | Rating, Experience Assessment, Review Assessment: Thoroughness In Paper Reading, Review Assessment: Checking Correctness Of Derivations And Theory, Review Assessment: Checking Correctness Of Experiments | - | - |
| ICLR-2021 | Review | Rating, Confidence | - | - |
| ICLR-2022 | Summary Of The Paper, Main Review, Summary Of The Review | Recommendation, Confidence, Correctness, Technical Novelty and Significance, Empirical Novelty and Significance | Flag For Ethics Review | - |
| ICLR-2023 | Summary Of The Paper, Strength And Weaknesses, Clarity, Quality, Novelty and Reproducibility, Summary Of The Review | Recommendation, Confidence, Correctness, Technical Novelty And Significance, Empirical Novelty And Significance | Flag For Ethics Review | - |
| Category | Examples |
| Section | sec.5 , experiments section |
| Table | Table 1 , Tab.1 |
| Figure | Figure 2 , Fig. 2 , Fig. 2a , |
| Equation | Equation 5 , Eq.5 , Eq. (5) |
| Algorithm | Algorithm 1 , Alg. 1 |
| Line | Line 100 , L545-547 , l. 66 , |
| min | max | median | mean | |
| LEN | 0.03 | 28.29 | 2.49 | 2.85 |
| ITX | 1.00 | 99.00 | 11.00 | 12.19 |
| REQ | 0.00 | 72.00 | 4.00 | 5.73 |
| ACT | 0.00 | 5.00 | 2.50 | 2.53 |
| EXL | 0.00 | 103.00 | 2.00 | 2.97 |
| GND | 0.00 | 5.00 | 3.00 | 3.08 |
| ICLR-2019 | ICLR-2020 | ICLR-2021 | ICLR-2022 | ICLR-2023 | ICLR-2024 | ICLR-2025 | |
| ICLR-2018 | [-0.004, 0.022] | [-0.002, 0.028] | [0.017, 0.046] | [0.011, 0.040] | [0.003, 0.031] | [0.005, 0.032] | [0.023, 0.051] |
| ICLR-2019 | - | [-0.008, 0.015] | [0.009, 0.035] | [0.005, 0.032] | [-0.003, 0.023] | [-0.002, 0.020] | [0.017, 0.040] |
| ICLR-2020 | - | - | [0.006, 0.031] | [0.002, 0.026] | [-0.007, 0.018] | [-0.007, 0.017] | [0.012, 0.036] |
| ICLR-2021 | - | - | - | [-0.017, 0.010] | [-0.025, 0.000] | [-0.026, 0.000] | [-0.009, 0.019] |
| ICLR-2022 | - | - | - | - | [-0.022, 0.004] | [-0.021, 0.003] | [-0.003, 0.022] |
| ICLR-2023 | - | - | - | - | - | [-0.011, 0.013] | [0.006, 0.034] |
| NeurIPS-2022 | NeurIPS-2023 | NeurIPS-2024 | NeurIPS-2025 | |
| NeurIPS-2021 | [-0.022, 0.002] | [-0.025, 0.002] | [-0.032, -0.006] | [-0.015, 0.010] |
| NeurIPS-2022 | - | [-0.013, 0.012] | [-0.021, 0.005] | [-0.003, 0.020] |
| NeurIPS-2023 | - | - | [-0.022, 0.006] | [-0.004, 0.022] |
| NeurIPS-2024 | - | - | - | [0.003, 0.029] |
| ARR-2024 | ARR-2025 | |
| ARR-2022 | [-0.013, 0.017] | [-0.015, 0.015] |
| ARR-2024 | - | [-0.014, 0.010] |
| ICLR-2019 | ICLR-2020 | ICLR-2021 | ICLR-2022 | ICLR-2023 | ICLR-2024 | ICLR-2025 | |
| ICLR-2018 | [-0.004, 0.015] | [-0.002, 0.014] | [0.011, 0.029] | [0.019, 0.036] | [0.020, 0.039] | [0.009, 0.027] | [0.015, 0.031] |
| ICLR-2019 | - | [-0.008, 0.009] | [0.005, 0.024] | [0.012, 0.031] | [0.014, 0.034] | [0.003, 0.021] | [0.009, 0.026] |
| ICLR-2020 | - | - | [0.004, 0.023] | [0.012, 0.030] | [0.014, 0.034] | [0.003, 0.020] | [0.009, 0.025] |
| ICLR-2021 | - | - | - | [-0.002, 0.016] | [0.000, 0.019] | [-0.010, 0.007] | [-0.005, 0.011] |
| ICLR-2022 | - | - | - | - | [-0.007, 0.010] | [-0.019, 0.000] | [-0.012, 0.004] |
| ICLR-2023 | - | - | - | - | - | [-0.021, -0.002] | [-0.016, 0.003] |
| NeurIPS-2022 | NeurIPS-2023 | NeurIPS-2024 | NeurIPS-2025 | |
| NeurIPS-2021 | [-0.013, 0.003] | [-0.015, 0.0] | [-0.017, -0.003] | [-0.007, 0.010] |
| NeurIPS-2022 | - | [-0.01, 0.005] | [-0.012, 0.002] | [-0.001, 0.014] |
| NeurIPS-2023 | - | - | [-0.009, 0.003] | [0.001, 0.015] |
| NeurIPS-2024 | - | - | - | [0.004, 0.018] |
| ARR-2024 | ARR-2025 | |
| ARR-2022 | [-0.009, 0.005] | [-0.003, 0.013] |
| ARR-2024 | - | [0.001, 0.013] |
| ICLR-2019 | ICLR-2020 | ICLR-2021 | ICLR-2022 | ICLR-2023 | ICLR-2024 | ICLR-2025 | |
| ICLR-2018 | [-0.010, 0.010] | [-0.010, 0.010] | [0.000, 0.020] | [0.000, 0.031] | [0.020, 0.041] | [-0.010, 0.010] | [-0.010, 0.010] |
| ICLR-2019 | - | [-0.010, 0.010] | [0.000, 0.020] | [0.000, 0.031] | [0.020, 0.041] | [-0.010, 0.010] | [-0.010, 0.010] |
| ICLR-2020 | - | - | [0.000, 0.020] | [0.000, 0.031] | [0.020, 0.041] | [-0.010, 0.010] | [-0.010, 0.010] |
| ICLR-2021 | - | - | - | [-0.010, 0.020] | [0.010, 0.031] | [-0.020, 0.000] | [-0.020, 0.000] |
| ICLR-2022 | - | - | - | - | [0.000, 0.023] | [-0.031, -0.010] | [-0.031, 0.000] |
| ICLR-2023 | - | - | - | - | - | [-0.041, -0.020] | [-0.041, -0.020] |
| NeurIPS-2022 | NeurIPS-2023 | NeurIPS-2024 | NeurIPS-2025 | |
| NeurIPS-2021 | [-0.020, 0.000] | [-0.031, -0.010] | [-0.031, -0.010] | [-0.031, -0.010] |
| NeurIPS-2022 | - | [-0.010, 0.010] | [-0.010, 0.010] | [-0.010, 0.010] |
| NeurIPS-2023 | - | - | [-0.010, 0.010] | [-0.010, 0.010] |
| NeurIPS-2024 | - | - | - | [-0.010, 0.010] |
| ARR-2024 | ARR-2025 | |
| ARR-2022 | [-0.020, 0.000] | [-0.020, 0.000] |
| ARR-2024 | - | [-0.010, 0.010] |
| ICLR-2019 | ICLR-2020 | ICLR-2021 | ICLR-2022 | ICLR-2023 | ICLR-2024 | ICLR-2025 | |
| ICLR-2018 | [-0.014, 0.015] | [0.000, 0.028] | [0.000, 0.028] | [0.000, 0.028] | [0.000, 0.028] | [0.000, 0.028] | [0.014, 0.042] |
| ICLR-2019 | - | [-0.008, 0.014] | [-0.001, 0.028] | [0.000, 0.028] | [-0.008, 0.014] | [0.000, 0.028] | [0.005, 0.042] |
| ICLR-2020 | - | - | [-0.014, 0.014] | [0.000, 0.014] | [-0.014, 0.014] | [0.000, 0.014] | [0.000, 0.028] |
| ICLR-2021 | - | - | - | [-0.014, 0.014] | [-0.014, 0.014] | [-0.014, 0.014] | [0.000, 0.028] |
| ICLR-2022 | - | - | - | - | [-0.014, 0.014] | [-0.014, 0.014] | [0.000, 0.028] |
| ICLR-2023 | - | - | - | - | - | [-0.008, 0.014] | [0.000, 0.028] |
| NeurIPS-2022 | NeurIPS-2023 | NeurIPS-2024 | NeurIPS-2025 | |
| NeurIPS-2021 | [0.000, 0.028] | [0.000, 0.028] | [-0.014, 0.014] | [0.000, 0.014] |
| NeurIPS-2022 | - | [-0.014, 0.014] | [-0.014, 0.000] | [-0.014, 0.014] |
| NeurIPS-2023 | - | - | [-0.014, 0.000] | [-0.014, 0.014] |
| NeurIPS-2024 | - | - | - | [0.000, 0.014] |
| ARR-2024 | ARR-2025 | |
| ARR-2022 | [-0.014, 0.014] | [-0.014, 0.014] |
| ARR-2024 | - | [-0.014, 0.014] |
| ICLR-2019 | ICLR-2020 | ICLR-2021 | ICLR-2022 | ICLR-2023 | ICLR-2024 | ICLR-2025 | |
| ICLR-2018 | [-0.016, 0.067] | [0.004, 0.082] | [0.025, 0.111] | [0.017, 0.095] | [-0.004, 0.077] | [0.027, 0.100] | [0.065, 0.143] |
| ICLR-2019 | - | [-0.017, 0.051] | [0.008, 0.083] | [0.000, 0.067] | [-0.017, 0.043] | [0.007, 0.072] | [0.047, 0.111] |
| ICLR-2020 | - | - | [-0.003, 0.063] | [-0.020, 0.050] | [-0.032, 0.027] | [-0.006, 0.056] | [0.030, 0.093] |
| ICLR-2021 | - | - | - | [-0.051, 0.024] | [-0.069, 0.003] | [-0.039, 0.033] | [-0.002, 0.070] |
| ICLR-2022 | - | - | - | - | [-0.050, 0.013] | [-0.024, 0.040] | [0.019, 0.083] |
| ICLR-2023 | - | - | - | - | - | [0.000, 0.060] | [0.034, 0.100] |
| NeurIPS-2022 | NeurIPS-2023 | NeurIPS-2024 | NeurIPS-2025 | |
| NeurIPS-2021 | [-0.045, 0.010] | [-0.033, 0.021] | [-0.040, 0.020] | [0.000, 0.061] |
| NeurIPS-2022 | - | [-0.014, 0.040] | [-0.020, 0.040] | [0.020, 0.081] |
| NeurIPS-2023 | - | - | [-0.040, 0.023] | [0.005, 0.065] |
| NeurIPS-2024 | - | - | - | [0.004, 0.076] |
| ARR-2024 | ARR-2025 | |
| ARR-2022 | [-0.031, 0.080] | [-0.022, 0.080] |
| ARR-2024 | - | [-0.050, 0.057] |
| ICLR-2019 | ICLR-2020 | ICLR-2021 | ICLR-2022 | ICLR-2023 | ICLR-2024 | ICLR-2025 | |
| ICLR-2018 | [-0.001, 0.010] | [-0.001, 0.010] | [0.005, 0.010] | [0.009, 0.010] | [-0.001, 0.010] | [-0.001, 0.010] | [-0.001, 0.010] |
| ICLR-2019 | - | [-0.010, 0.010] | [0.000, 0.010] | [0.000, 0.010] | [-0.010, 0.010] | [-0.010, 0.010] | [-0.010, 0.010] |
| ICLR-2020 | - | - | [0.000, 0.010] | [0.000, 0.010] | [-0.010, 0.010] | [-0.010, 0.010] | [-0.010, 0.010] |
| ICLR-2021 | - | - | - | [0.000, 0.000] | [-0.010, 0.000] | [-0.010, 0.000] | [-0.010, 0.000] |
| ICLR-2022 | - | - | - | - | [-0.010, 0.000] | [-0.010, 0.000] | [-0.010, 0.000] |
| ICLR-2023 | - | - | - | - | - | [-0.010, 0.010] | [-0.010, 0.010] |
| NeurIPS-2022 | NeurIPS-2023 | NeurIPS-2024 | NeurIPS-2025 | |
| NeurIPS-2021 | [-0.010, 0.000] | [-0.019, 0.000] | [-0.019, 0.000] | [-0.019, 0.000] |
| NeurIPS-2022 | - | [-0.010, 0.000] | [-0.010, 0.00] | [-0.010, 0.000] |
| NeurIPS-2023 | - | - | [-0.010, 0.010] | [-0.010, 0.010] |
| NeurIPS-2024 | - | - | - | [-0.010, 0.010] |
| ARR-2024 | ARR-2025 | |
| ARR-2022 | [-0.010, 0.000] | [-0.010, 0.000] |
| ARR-2024 | - | [-0.010, 0.000] |
| ICLR-2019 | ICLR-2020 | ICLR-2021 | ICLR-2022 | ICLR-2023 | ICLR-2024 | ICLR-2025 | |
| ICLR-2018 | [-0.036, 0.040] | [0.000, 0.040] | [0.000, 0.076] | [0.000, 0.044] | [-0.040, 0.040] | [0.000, 0.040] | [0.000, 0.094] |
| ICLR-2019 | - | [0.000, 0.036] | [0.000, 0.068] | [0.000, 0.040] | [-0.040, 0.036] | [0.000, 0.036] | [0.000, 0.080] |
| ICLR-2020 | - | - | [0.000, 0.052] | [0.000, 0.039] | [-0.040, 0.000] | [0.000, 0.000] | [0.000, 0.067] |
| ICLR-2021 | - | - | - | [-0.050, 0.032] | [-0.073, 0.000] | [-0.050, 0.000] | [-0.047, 0.067] |
| ICLR-2022 | - | - | - | - | [-0.040, 0.000] | [-0.037, 0.000] | [-0.024, 0.067] |
| ICLR-2023 | - | - | - | - | - | [0.00, 0.040] | [0.000, 0.092] |
| NeurIPS-2022 | NeurIPS-2023 | NeurIPS-2024 | NeurIPS-2025 | |
| NeurIPS-2021 | [-0.067, 0.044] | [-0.067, 0.040] | [-0.067, 0.000] | [-0.044, 0.067] |
| NeurIPS-2022 | - | [-0.050, 0.044] | [-0.050, 0.000] | [-0.030, 0.067] |
| NeurIPS-2023 | - | - | [-0.050, 0.000] | [-0.010, 0.067] |
| NeurIPS-2024 | - | - | - | [0.000, 0.067] |
| ARR-2024 | ARR-2025 | |
| ARR-2022 | [-0.100, 0.057] | [-0.100, 0.050] |
| ARR-2024 | - | [-0.057, 0.057] |
| ICLR-2019 | ICLR-2020 | ICLR-2021 | ICLR-2022 | ICLR-2023 | ICLR-2024 | ICLR-2025 | |
| ICLR-2018 | [-0.014, 0.03] | [-0.008, 0.032] | [0.027, 0.064] | [0.032, 0.064] | [-0.001, 0.037] | [0.028, 0.063] | [0.047, 0.076] |
| ICLR-2019 | - | [-0.018, 0.027] | [0.019, 0.060] | [0.022, 0.060] | [-0.013, 0.034] | [0.019, 0.058] | [0.037, 0.073] |
| ICLR-2020 | - | - | [0.015, 0.052] | [0.017, 0.055] | [-0.015, 0.027] | [0.015, 0.053] | [0.033, 0.068] |
| ICLR-2021 | - | - | - | [-0.013, 0.016] | [- 0.048, -0.009] | [-0.016, 0.017] | [0.002, 0.030] |
| ICLR-2022 | - | - | - | - | [- 0.048, -0.014] | [-0.016, 0.014] | [0.003, 0.025] |
| ICLR-2023 | - | - | - | - | - | [0.011, 0.044] | [0.028, 0.059] |
| NeurIPS-2022 | NeurIPS-2023 | NeurIPS-2024 | NeurIPS-2025 | |
| NeurIPS-2021 | [-0.014, 0.018] | [0.000, 0.030] | [-0.016, 0.014] | [0.005, 0.035] |
| NeurIPS-2022 | - | [0.001, 0.024] | [-0.017, 0.009] | [0.005, 0.032] |
| NeurIPS-2023 | - | - | [- 0.028, -0.005] | [-0.006, 0.017] |
| NeurIPS-2024 | - | - | - | [0.010, 0.034] |
| ARR-2024 | ARR-2025 | |
| ARR-2022 | [-0.033, 0.003] | [-0.018, 0.014] |
| ARR-2024 | - | [-0.005, 0.032] |
| ICLR-2019 | ICLR-2020 | ICLR-2021 | ICLR-2022 | ICLR-2023 | ICLR-2024 | ICLR-2025 | |
| ICLR-2018 | [-0.014, 0.026] | [-0.005, 0.030] | [-0.005, 0.04] | [-0.003, 0.035] | [-0.008, 0.024] | [-0.013, 0.022] | [-0.002, 0.034] |
| ICLR-2019 | - | [-0.015, 0.025] | [-0.017, 0.035] | [-0.011, 0.029] | [-0.018, 0.020] | [-0.020, 0.018] | [-0.010, 0.029] |
| ICLR-2020 | - | - | [-0.015, 0.030] | [-0.014, 0.023] | [-0.020, 0.011] | [-0.023, 0.011] | [-0.013, 0.022] |
| ICLR-2021 | - | - | - | [-0.028, 0.024] | [-0.032, 0.012] | [-0.034, 0.005] | [-0.027, 0.020] |
| ICLR-2022 | - | - | - | - | [-0.026, 0.010] | [-0.031, 0.008] | [-0.022, 0.019] |
| ICLR-2023 | - | - | - | - | - | [-0.021, 0.013] | [-0.011, 0.026] |
| NeurIPS-2022 | NeurIPS-2023 | NeurIPS-2024 | NeurIPS-2025 | |
| NeurIPS-2021 | [-0.030, 0.010] | [-0.031, 0.012] | [-0.035, -0.000] | [-0.026, 0.002] |
| NeurIPS-2022 | - | [-0.021, 0.028] | [-0.027, 0.017] | [-0.023, 0.016] |
| NeurIPS-2023 | - | - | [-0.033, 0.018] | [-0.024, 0.022] |
| NeurIPS-2024 | - | - | - | [-0.018, 0.022] |
| ARR-2024 | ARR-2025 | |
| ARR-2022 | [-0.016, 0.021] | [-0.016, 0.015] |
| ARR-2024 | - | [-0.017, 0.010] |
| Aspect | |
| Comprehensiveness | 0.179 |
| Usage of Technical Terms | -0.118 |
| Factuality | -0.074 |
| Sentiment Polarity | 0.267 |
| Politeness | -0.116 |
| Vagueness | 0.156 |
| Aspect | QWA | |
| Substantiveness | 0.615 | - |
| Actionability | 0.531 | - |
| Grounding | 0.493 | - |
| Stance | - | 0.953 |
| Objectivity | - | 0.988 |
| Readability | - | 0.982 |
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