The Parity Index · live
Cheaper models are quietly beating the expensive ones.
Every router ranks models by price. We rank them by whether a cheaper model, tuned by our patent-pending proof, actually held or beat the model you are paying for, on your real prompts. Across 16,764 blind tests, it did 85.5% of the time.
This is not the same prompt sent to two models. Our patent-pending proof optimises how the cheaper model is used for your task first, then a blind judge checks the result. That step is the product.
The leaderboard
Cheaper models winning on quality right now.
How often each cheaper model, once tuned by Parity's patent-pending proof, held or beat the more expensive one it was tested against, on real production prompts, ranked. A green badge means it produced genuinely better work, not just as good.
Head to head
Examples where a cheaper model beat a frontier model.
Each of these is a real head to head on production prompts, and what you are looking at is how often the cheaper model came back with better work than the more expensive one it was tested against, once our patent-pending proof had tuned it for the task. Aggregate across many companies.
The cheaper model produced better work 45% of the time, and held or beat it 85% of the time, across 40 blind comparisons.
The cheaper model produced better work 36% of the time, and held or beat it 36% of the time, across 50 blind comparisons.
The cheaper model produced better work 32% of the time, and held or beat it 89% of the time, across 142 blind comparisons.
The cheaper model produced better work 30% of the time, and held or beat it 78% of the time, across 50 blind comparisons.
The cheaper model produced better work 30% of the time, and held or beat it 98% of the time, across 40 blind comparisons.
The cheaper model produced better work 28% of the time, and held or beat it 80% of the time, across 40 blind comparisons.
The cheaper model produced better work 21% of the time, and held or beat it 82% of the time, across 225 blind comparisons.
The cheaper model produced better work 20% of the time, and held or beat it 40% of the time, across 75 blind comparisons.
We also publish where cheaper models failed.
If we only showed you the wins this would not be worth much, so every comparison we run lands in one of three outcomes and you can see all three. The ones that fail never switch, they stay on the model you are already paying for.
77.5% matched. Same quality as the model in use.
8% beat it. Genuinely better than the dearer model.
14.5% did not hold. These prompts stay on the original.
Start from your model
Which model are you paying for now?
Pick the model you run today and you can see which cheaper ones have actually been tested against it, and how often they held. These are the real comparisons we have run, so some have more behind them than others, and where the sample is still small we say so.
142 blind comparisons
225 blind comparisons
75 blind comparisons
50 blind comparisons, early data on a small sample
What it is worth
What that looks like on your bill.
A percentage is easy to skim past, so put your own number in and see the range on the work a cheaper model passes on. It is a band rather than a figure because it genuinely varies prompt by prompt.
On the work that passes, per month
$1,500 to $3,000
Over a year
$18,000 to $36,000
This is the 30 to 60% band applied to your number, and it only covers the prompts a cheaper model actually passes on. Prompts that fail stay on the model you are using now, so treat this as the range on proven work rather than a quote. Your own report gives you the real figure for your traffic.
By kind of work
Which work is safest to move.
Not all prompts are equal. This is how often a cheaper model held or beat the original, by the kind of work. Your own mix decides your own number.
Why this ranking exists
No other router keeps this number.
A router chooses a cheaper model on price, latency and uptime, before it has seen the answer. A degraded reply and a good one both come back the same way, so the quality question is never measured. It just becomes your problem later.
Parity is the first router that proves quality when you switch to a cheaper model. Cheaper candidates run against your real prompts, a blind judge decides whether the cheaper output matched or beat your current one, only a proven model is ever offered as a switch, and fallback to your original is instant. This ranking is the aggregate of every one of those judgements. It is data only Parity can produce, because only Parity runs the proof.
How it is measured
- The cheaper model is tuned first, not sent the raw prompt. This is the part that matters. Our patent-pending proof works out how to get the cheaper model to do your task well, then tests that. The same prompt sent blindly to a cheaper model would often fall short. The result is what Parity makes the cheaper model produce, which is exactly why you cannot get this number anywhere else.
- On real prompts, not a benchmark. Every comparison uses a company's real production traffic, never a public test set that can be gamed.
- A blind judge in your own model class. The judge does not know which output is the cheaper one, and the bar is set by how much your current model already disagrees with itself run to run.
- Three separate dimensions. Format, categorical correctness and meaning are each checked, so a cheaper model has to hold on all of them, not just look similar.
- Aggregate and anonymous. The ranking pools results across companies. We never publish which model was proven for any single company, or any prompt content.
The only number that decides it is yours.
This ranking is the average across many companies. Whether a cheaper model holds on your prompts is specific to you. Connect your traffic or start with a JSONL export of past requests, and see your own proof, before anything switches. No proof, no charge. Not for coding agents.
Aggregate figures as of August 22, 2026. Proof runs March 27, 2026 to August 3, 2026. Refreshed monthly.