# Task 2.5 — Table 7 Counterfactual Ablation

| Row | Validation Item | Key Result | Verdict |
|---|---|---|---|
| 1 | Noise floor τ | L1 p99 = 0.000000, PSNR-equiv = 160.0 dB | deterministic |
| 2 | gsplat vs native rank consistency | Median Spearman ρ = 1.000 (n=19 scenes) | consistent |
| 3 | A+B interaction | joint=0.1442, sum_marginals=0.1452, interaction=-0.0010 (-0.7%) | non-additive |
| 4 | SH degree ablation | zero_all=0.0218, zero_l2up=0.0181, l1_contrib=0.0037 | direction-consistent |

## Row Interpretations

### Row 1 — Noise Floor
gsplat rasterization is deterministic on identical inputs.
The noise floor L1 p99 = 0.00e+00 establishes τ for counterfactual delta interpretation.

### Row 2 — Rasterizer Consistency  
Median Spearman ρ = 1.000 across 19 scenes confirms that
gsplat-based counterfactual profiling preserves method rank ordering consistent with native rasterizers.

### Row 3 — A+B Interaction
The interaction residual = -0.0010 (-0.7% of sum-of-marginals)
demonstrates that SH and opacity counterfactuals are non-additive.
This validates the independent-channel analysis assumption in §5.3.

### Row 4 — SH Degree Ablation
Direction consistent between full AC zeroing and l≥2-only zeroing.
l=1 contribution = 0.0037, indicating l=1 carries non-trivial signal.