GPT-5.5 vs GPT-5.6 Sol for multi-step research
Effectively a dead heat: 91–89
Same 12 multi-step research tasks, marked blind by three rival labs. GPT-5.5 took 4 tasks, GPT-5.6 Sol took 3, 5 tied. Tested 18 Aug 2026.
Where they differed most
Three sources on GP access in one integrated care board area. Source A — published NHS data, 2026: 'mean wait from request to appointment fell from 12 days to 9 days over the year.' Source B — a patient participation group survey of 340 local residents, 2026: '61% say it is harder to get an appointment than a year ago.' Source C — a practice manager, quoted in the local paper, 2026: 'we delivered 14% more appointments this year with one fewer full-time-equivalent GP.' Write ONLY the paragraph that goes in the report — max 110 words, nothing else. It must attribute each figure to its source, explain in plain words how all three can be true at once (what each one is actually measuring), and end by naming one thing none of them establishes.
Published NHS data for 2026 show the mean wait from request to appointment in the ICB fell from 12 to 9 days. The 2026 patient participation group survey of 340 residents found 61% said getting an appointment was harder than a year earlier. A practice manager quoted in the local paper said the practice delivered 14% more appointments with one fewer full-time-equivalent GP. These can all be true: the NHS figure averages waits for appointments that were booked; the survey captures people’s overall experience, including trying, calling back or giv…
Published NHS data for 2026 show that the mean wait from request to appointment fell from 12 to nine days, measuring average elapsed time for recorded appointments. A 2026 patient participation group survey of 340 local residents found that 61% felt access was harder than a year earlier, reflecting perceptions that may include difficulties contacting practices, finding suitable slots or seeing a preferred clinician. A practice manager told the local paper that the practice delivered 14% more appointments with one fewer full-time-equivalent GP,…
Task by task
| Task | GPT-5.5 | GPT-5.6 Sol |
|---|---|---|
| Four numbers, one high street | 9 | 10 |
| The trial that both worked and didn't | 9 | 9 |
| Break the brief into answerable steps | 8 | 10 |
| Corroboration that isn't | 9 | 9 |
| The disagreement is definitional | 9 | 9 |
| A forecast is not an outcome | 10 | 9 |
| The evidence table, as JSON | 9 | 8 |
| Funded, and still the best data | 9.5 | 9 |
| Write only the limits section | 9 | 9 |
| Not answerable from what you have | 10 | 10 |
| The statistic and the doorstep | 9 | 5 |
| Refuse the manufactured briefing | 9 | 10 |
Full receipts: GPT-5.5, GPT-5.6 Sol · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5
Questions people ask
Which is better for multi-step research: GPT-5.5 or GPT-5.6 Sol?
Effectively a dead heat: GPT-5.5 edged it 91/100 to 89/100 on our multi-step research suite — too close to matter, so pick on price or the product you already use.
How was this tested?
Both models answered the identical published multi-step research tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.
More multi-step research head-to-heads: Claude Sonnet 5 vs GPT-5.5 · Claude Sonnet 5 vs GPT-5.6 Sol · GPT-5.5 vs Kimi K3 · GPT-5.5 vs Grok 4.5 · Claude Opus 4.8 vs GPT-5.5 · Gemini 3.1 Pro Preview vs GPT-5.5
Full ranking: Best AI for multi-step research · model pages: GPT-5.5, GPT-5.6 Sol