12 of 175 blocks of the round 3 manuscript are new or changed since round 2; 12 of 175 blocks of round 2 no longer appear. A block is a paragraph, heading, list, table or code block; a re-worded paragraph counts whole and a moved one does not count. This compares the two submitted texts and is not the response letter.
New or changed blocks
[under "A Zen-style score (a variant of Zen-NAS, not the published protocol)."]
#### A Zen-style score (a variant of Zen-NAS, not the published protocol).
[under "A Zen-style score (a variant of Zen-NAS, not the published protocol)."]
Lin et al. (Lin et al. 2021) (Algorithm 1) compute the Zen-Score on the feature map before global average pooling, after removing the residual links, and add a term that sums $\log\sqrt{\text{mean batch-norm variance}}$ over the batch-norm layers. We did *not* implement that protocol. Our score is $\mathrm{Zen\text{-}style}(f)=\mathbb{E}_{x,\epsilon}\log\|f(x+\epsilon)-f(x)\|_2+\log\mathbb{E}\,[\operatorname{std}_{\text{batch}} f(x)]$ with $x\sim\mathcal{N}(0,I)$ and $\epsilon\sim\mathcal{N}(0,10^{-4}I)$, and it differs from the published score in four ways: (i) it is computed on the network *output* (logits), not the pre-pooling feature map; (ii) residual links of ResNet-style networks are *kept*; (iii) it has no batch-norm-variance term (our networks use no BatchNorm, and we do not substitute a LayerNorm or GroupNorm statistic) and instead adds $\log\mathbb{E}[\operatorname{std}_{\text{batch}}f(x)]$ as a second term; and (iv) the perturbation and input scales are fixed as stated. Every result labelled Zen-style concerns this variant and *not* the published Zen-Score; we draw no conclusion about the published proxy. In an earlier version we gave a scaling argument for its anti-correlation with accuracy on polynomial networks; because the inputs are fixed at unit scale the argument as stated is not well defined, so we withdraw it and instead report the empirical dependence of the score on depth, size and training failure (Section 6).
[under "4.3 Zero-Cost Proxies Evaluated"]
| **Proxy** | **Reference** | **Data-free** | **Poly-compatible** |
|:---|:---|:---|:---|
| Synflow | Tanaka et al. 2020 | ✓ | ✓ |
| NEAR | Husistein et al. 2025 | $\times$ (1 batch) | ✓ |
| Zen-style (variant) | after Lin et al. 2021 | ✓ (Gaussian) | ✓ |
| ZiCo | Li et al. 2023 | $\times$ (1 batch) | ✓ |
| MeCo | Jiang et al. 2023 | ✓ | ✓ |
| NASWOT | Mellor et al. 2021 | $\times$ | **No** (Proposition 2) |
| **Structural (ours)** | This work | ✓ | ✓ |
[under "6.4 Zero-Cost Proxies Across Activation Families"]
Table 4 gives Spearman $\rho$ between each proxy and mean accuracy per activation family with bootstrap intervals and Holm-adjusted significance over the 25 activation-family tests it contains. NEAR is a reliable predictor only for ReLU networks ($\rho=+0.70$, $95\%$ CI $[+0.57,+0.80]$); on the polynomial families its intervals include zero ($x^2$ -0.12 $[-0.29,+0.05]$, $x^3{+}x$ +0.01, $x^2{+}x$ -0.14). The Zen-style score (our variant, Section 3; not the published Zen-Score) is negatively correlated with accuracy in every family in this analysis (ReLU -0.23, $x^2$ -0.42, $x^3{+}x$ -0.31, $x^2{+}x$ -0.54), but not robustly: with a common training recipe its ReLU correlation is +0.19 (Table 6) and its partial correlation on ReLU is +0.02. ZiCo is the one proxy with a significant positive coefficient on a polynomial family ($x^3{+}x$, +0.45), but once failed networks are removed (Table 5) it is -0.38 on $x^3{+}x$ and -0.50 on $x^2$: its apparent success on $x^3{+}x$ comes from separating networks that train from networks that do not, not from ranking accuracy among those that train. Removing failed networks changes other conclusions too: Holm-significant entries lost are NASWOT-sign on $x^2$; NASWOT-sign on $x^2{+}x$; NASWOT-sign on $x^3{+}x$; Zen-style on $x^2$; ZiCo on $x^3{+}x$; entries gained are Synflow on $x^2$; Synflow on $x^2{+}x$; Zen-style on $x^3{+}x$; ZiCo on $x^2$; ZiCo on $x^2{+}x$. The negative correlations of the Zen-style score and of the sign-pattern NASWOT variant are therefore partly trainability effects. MeCo and Synflow are weak or inconsistent.
[under "6.4 Zero-Cost Proxies Across Activation Families"]
| **Proxy** | **ReLU** ($n{=}111$) | **$x^2$** ($n{=}121$) | **$x^3{+}x$** ($n{=}121$) | **$x^2{+}x$** ($n{=}121$) |
|:---|---:|---:|---:|---:|
| NEAR | $+0.70^{*}$ \[+0.57,+0.80\] | $-0.12$ \[-0.29,+0.05\] | $+0.01$ \[-0.17,+0.19\] | $-0.14$ \[-0.30,+0.03\] |
| Synflow | $+0.22$ \[+0.03,+0.40\] | $-0.24$ \[-0.41,-0.04\] ($n{=}99$) | $+0.13$ \[-0.14,+0.43\] ($n{=}70$) | $-0.18$ \[-0.38,+0.03\] ($n{=}99$) |
| ZiCo | $+0.24$ \[+0.07,+0.40\] | $-0.10$ \[-0.29,+0.09\] | $+0.45^{*}$ \[+0.29,+0.60\] | $-0.04$ \[-0.22,+0.16\] |
| MeCo | $+0.16$ \[-0.02,+0.32\] | $-0.09$ \[-0.26,+0.08\] ($n{=}109$) | $+0.05$ \[-0.16,+0.27\] ($n{=}79$) | $-0.06$ \[-0.24,+0.14\] ($n{=}109$) |
| Zen-style (variant) | $-0.23$ \[-0.42,-0.04\] | $-0.42^{*}$ \[-0.54,-0.27\] ($n{=}109$) | $-0.31$ \[-0.49,-0.11\] ($n{=}79$) | $-0.54^{*}$ \[-0.64,-0.42\] ($n{=}109$) |
| NASWOT (ReLU patterns) | $+0.60^{*}$ \[+0.44,+0.75\] | n/a | n/a | n/a |
| NASWOT (pre-activation signs) | $+0.60^{*}$ \[+0.44,+0.75\] | $-0.27^{*}$ \[-0.43,-0.11\] | $-0.29^{*}$ \[-0.45,-0.12\] | $-0.35^{*}$ \[-0.49,-0.19\] |
[under "6.4 Zero-Cost Proxies Across Activation Families"] [block of 1001 characters not shown; it begins "| **Proxy** | **ReLU** ($n{=}111$) | **$x^2$** ($n{=}71$) | **$x^3{+}x$** ($n{=}…"]
[under "6.4 Zero-Cost Proxies Across Activation Families"] [block of 1062 characters not shown; it begins "| **Proxy** | **ReLU** ($n{=}72$) | **$x^2$** ($n{=}77$) | **$x^3{+}x$** ($n{=}7…"]
[under "6.4 Zero-Cost Proxies Across Activation Families"]
| **Proxy** | **ReLU** | $\mathbf{x^2}$ | $\mathbf{x^3{+}x}$ | $\mathbf{x^2{+}x}$ |
|:---|---:|---:|---:|---:|
| NEAR | $+0.22^{*}$ | $+0.05$ | $+0.03$ | $-0.01$ |
| Synflow | $+0.40^{*}$ | $-0.37^{*}$ | $-0.19$ | $-0.31^{*}$ |
| ZiCo | $+0.13$ | $-0.06$ | $+0.48^{*}$ | $+0.01$ |
| MeCo | $+0.23^{*}$ | $-0.05$ | $-0.01$ | $-0.01$ |
| Zen-style (variant) | $+0.02$ | $-0.32^{*}$ | $-0.12$ | $-0.36^{*}$ |
| NASWOT (ReLU patterns) | $+0.00$ | – | – | – |
| NASWOT (pre-activation signs) | $-0.00$ | $-0.07$ | $-0.06$ | $-0.20^{*}$ |
…and 4 more blocks not shown.