Does the Explanation Drift Before the Guarantee? Label-Free Early Warning on Evolving Graphs
Organizations: Faculty of Information and Communication Technology, Wroclaw University of Science and Technology · independent researcher
Abstract
Deployed models can fail silently as the world they describe evolves. Attribution drift has served as an early warning in tabular data; we ask whether, in graph streams, a model's own explanations can forewarn the loss of nominal conformal coverage. Doing so requires repairing the naive drift statistic twice. A vanishing edge loses mask mass regardless of whether the model relied on it, so we condition the importance on edge presence. Evolving graphs also break edge identity: a relabelling that changes nothing shifts the identity-based statistic by 0.69 on synthetic graphs and 0.83 on real ego-networks, whereas aggregating over structural roles brings both to 0.0 and stays well-defined when the support changes. We test six pre-registered regimes on thirty seeds each. A two-channel monitor, tracking conditional mask mass and its distribution over roles, precedes coverage collapse by 8 to 14.5 steps across four gradual regimes (node addition, removal, replacement, and edge thinning), all surviving Holm correction. A sudden knockout yields the expected zero lead, and a harmless change triggers no alarm. Leads track the length of the transitional phase (Spearman 0.79 over 150 runs). On real transaction ego-networks, the untuned mass channel forewarns staged drift by 27 steps and is the only channel, attributional or structural, that never alarms on a stationary stream. The main limitation is that the mass channel is blind to covariate drift, which breaks the guarantee in every run; the distributional channel detects it and also rescues the rewiring regime, so we report the two channels separately rather than as a union.
Figures & tables
| Regime | Stage-one mechanism | Support | Predicted lead |
|---|---|---|---|
| thinning | ’s density decays in place | fixed | |
| knockout | both motifs collapse at once | fixed | (no transitional phase) |
| add | ’s edges rewired through new nodes | grows | |
| remove | ’s nodes retired entirely | shrinks | |
| mix | removal of plus non-predictive traffic | both | |
| null | untouched; background-level traffic on | grows | silent |
| Regime | Pred. | (med.) | IQR | frac | Holm | Verdict | |
| thinning | confirmed | ||||||
| knockout | - | confirmed (control 1) | |||||
| add | failed; § 4.2 | ||||||
| remove | confirmed | ||||||
| mix | confirmed | ||||||
| null | silent | - | - | alarms | - | confirmed (control 2) |
| Regime | (median) | IQR | frac | Holm |
|---|---|---|---|---|
| thinning | ||||
| knockout | - | |||
| add | ||||
| remove | ||||
| mix | ||||
| Alarms on the controls, by channel: | ||||
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
| Channel | pooled | alarms on covariate | thinning | add | |
|---|---|---|---|---|---|
| (mass) | |||||
| (distribution) | |||||
| union | |||||
| degree MMD | |||||
| embedding MMD | |||||
| conditioned identity focus |
Distribution Shift Detection
Distribution shift detection identifies when data or model behavior changes between reference and deployment settings.
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