| Does a cheaper model save money? | Yes, measured per request: FrugalGPT matched the best single model at up to 98% lower cost, and AutoMix cut cost by more than half at comparable quality. FrugalGPT; AutoMix (NeurIPS 2024) | Measured |
| Does per-request routing beat one model per task? | Barely. Against a frozen best model per task, the best router gains 1.4 to 2.6 points and recovers 7.5% to 14.4% of the oracle headroom; the lower confidence bound on the gain is zero. Opportunity Is Not Realizability (preprint, 2026) | Supports task-level assignment |
| Do the routing methods differ much? | Little. The top 5 of 21 methods differ by 0.22 points on average, and a nearest-neighbour baseline is competitive. The Routing Plateau (preprint, 2026); RouterArena (ICLR 2026) | Routing is commoditising |
| When does a cascade pay? | When the check is accurate. With repository tests as the check, cascade routing scored 54.12 against 40.47 for routing on SWE-Bench, counting the cost of every call. A Unified Approach to Routing and Cascading (ICML 2025) | Keep cascades check-based |
| Does a leaderboard predict my task? | Weakly. Models move about six to seven rank positions between benchmark and downstream task, and top-three overlap is at most 0.25. Benchmarking the Benchmarks (preprint, 2026) | Measure on your own fixtures |
| How sure is "cleared the floor"? | A normal 95% interval at 100 items covered the true pass rate only 92.5% of the time in simulation; Wilson and Beta-Bernoulli intervals held their coverage. Don't Use the CLT in LLM Evals (ICML 2025) | Why the gate uses Wilson |
| Do hosted models change silently? | Yes. 11 of 31 third-party endpoints serving a Llama model returned something other than the reference weights. Model Equality Testing (ICLR 2025) | Why policies carry a fingerprint |
| Are cheap checks trustworthy? | Not by themselves. LLM-judge verifiers missed more wrong answers as the cheap model grew, and valid JSON did not mean correct fields. Cheap Verifiers, Large Blind Spots (preprint, 2026); ExtractBench (KDD 2026) | Program checks and a gold slice |