ModelSpec is an analysis of alternatives for AI models: it decides which models fit a job from your requirements, sourced benchmarks and real cost, and shows its work.
Gemini 3.1 Pro Preview vs Gemini 3.8 Flash for Regulated data on a budget, as of 2026-09-23
Find the cheapest offering with the data-handling commitments regulated workloads need.
Worked example as of 2026-09-23, from the public data image.
What the evidence says
The evidence separates them: Gemini 3.8 Flash leads for Regulated data on a budget, with a 43% chance of being the best model in the full lineup for this job, as of 2026-09-23.
Gemini 3.1 Pro Preview has an under 1% chance of matching or beating Gemini 3.8 Flash on this job's objective.
probability bands: a model joins the leader when P(its score >= the leader's) >= 0.25 under the score posteriors; a weighted capability with an 80% interval wider than 2.8 is not enough evidence
Decision status: answered. P(best) and score intervals retain the full ranked lineup for this job, including models beyond this pair and models with thin evidence. Models with unknown objective values remain unranked and are outside this probability. P(best) is not a head-to-head probability. Separation from this challenger need not mean a unique best model across that lineup.
Scores and score intervals use the objective's dimensionless normalised units. Cost per task is in USD for the selected offering and the applied spec's task size. When task size is omitted, the engine uses its documented default. Unavailable means the engine returned no value.
| Model | Score | Score interval | P(best), ranked job lineup | Cost per task, USD | Selected offering: provider / region / tier | Capability estimates and intervals |
|---|---|---|---|---|---|---|
| Gemini 3.1 Pro Preview | 0.640982 | [0.616966, 0.664998] | under 1% | 0.128 | google-vertex-ai / global / standard |
|
| Gemini 3.8 Flash | 0.819061 | [0.790499, 0.847622] | 43% | 0.045 | google-vertex-ai / global / standard |
|
HIPAA-ready offerings; cheapest first, quality kept.
Requirements
offering.data.trains_on_customer_data = No: Customer prompts and outputs must not be available for model training.offering.data.zero_retention = Yes: The provider must offer a mode that stores neither prompts nor outputs.offering.attestation.baa = Yes: The provider must offer a HIPAA business associate agreement for the service.
Preferences
-offering.cost_per_task: Prefer the lower task cost after the compliance gates pass.chat_preference: Keep a quality signal so a cheap but poor assistant does not win on cost alone.
Applied template spec
spec_version- 1
where- offering.data.trains_on_customer_data = No
- offering.data.zero_retention = Yes
- offering.attestation.baa = Yes
optimizeweights-offering.cost_per_task- 0.7
chat_preference- 0.3
Evidence for Gemini 3.1 Pro Preview
| Benchmark | Version | Measurement | Unit | Published interval | Evidence date | Measurement conditions | Provenance |
|---|---|---|---|---|---|---|---|
| arena_elo_style_control | text_style_control / overall, latest split, revision 1880dbebff5b | 1486.81 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_business | text_style_control / industry_business_and_management_and_financial_operations, latest split, revision 1880dbebff5b | 1477.34 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_chinese | text_style_control / chinese, latest split, revision 1880dbebff5b | 1530.02 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_coding | text_style_control / coding, latest split, revision 1880dbebff5b | 1520.16 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_creative_writing | text_style_control / creative_writing, latest split, revision 1880dbebff5b | 1480.3 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_document | document / overall, latest split, revision 1880dbebff5b | 1443.92 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_english | text_style_control / english, latest split, revision 1880dbebff5b | 1489.13 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_expert | text_style_control / expert, latest split, revision 1880dbebff5b | 1509.05 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_factuality | text_factuality / overall, latest split, revision 1880dbebff5b | 1471.8 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_french | text_style_control / french, latest split, revision 1880dbebff5b | 1501.84 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_german | text_style_control / german, latest split, revision 1880dbebff5b | 1493.58 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_hard_prompts | text_style_control / hard_prompts, latest split, revision 1880dbebff5b | 1507.49 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_industry_entertainment_sports_media | text_style_control / industry_entertainment_and_sports_and_media, latest split, revision 1880dbebff5b | 1467.54 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_industry_mathematical | text_style_control / industry_mathematical, latest split, revision 1880dbebff5b | 1485.24 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_industry_software_it_services | text_style_control / industry_software_and_it_services, latest split, revision 1880dbebff5b | 1511.95 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_instruction_following | text_style_control / instruction_following, latest split, revision 1880dbebff5b | 1481.01 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_japanese | text_style_control / japanese, latest split, revision 1880dbebff5b | 1494.05 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_korean | text_style_control / korean, latest split, revision 1880dbebff5b | 1458.5 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_legal | text_style_control / industry_legal_and_government, latest split, revision 1880dbebff5b | 1497.14 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_longer_query | text_style_control / longer_query, latest split, revision 1880dbebff5b | 1499.93 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_math | text_style_control / math, latest split, revision 1880dbebff5b | 1489.37 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_medicine | text_style_control / industry_medicine_and_healthcare, latest split, revision 1880dbebff5b | 1502.96 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_multi_turn | text_style_control / multi_turn, latest split, revision 1880dbebff5b | 1494.74 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_non_english | text_style_control / non_english, latest split, revision 1880dbebff5b | 1479.67 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_polish | text_style_control / polish, latest split, revision 1880dbebff5b | 1495.98 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_russian | text_style_control / russian, latest split, revision 1880dbebff5b | 1500.29 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_science | text_style_control / industry_life_and_physical_and_social_science, latest split, revision 1880dbebff5b | 1512.17 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_spanish | text_style_control / spanish, latest split, revision 1880dbebff5b | 1480.32 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_vision | vision_style_control / overall, latest split, revision 1880dbebff5b | 1278.69 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_vision_diagram | vision_style_control / diagram, latest split, revision 1880dbebff5b | 1308.97 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_vision_homework | vision_style_control / homework, latest split, revision 1880dbebff5b | 1311.09 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_vision_ocr | vision_style_control / ocr, latest split, revision 1880dbebff5b | 1292.97 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_writing | text_style_control / industry_writing_and_literature_and_language, latest split, revision 1880dbebff5b | 1480.94 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_webdev | webdev / overall, latest split, revision 1880dbebff5b | 1446.69 | Arena score (Elo scale) | Unavailable | 2026-09-23 |
| Source |
Missing facts for Gemini 3.1 Pro Preview
model.hardware_fit_indeterminate: unknownmodel.languages: unknownmodel.parameters_total: unknownorigin.base_lineage: not_disclosedorigin.weights_hosting: not_disclosedoffering.api_model_id: unknownoffering.attestation.soc2: not_disclosedoffering.private_deployment: unknownoffering.router_slug: unknownoffering.speed.throughput: unknownoffering.speed.time_to_first_token: unknown
Evidence for Gemini 3.8 Flash
| Benchmark | Version | Measurement | Unit | Published interval | Evidence date | Measurement conditions | Provenance |
|---|---|---|---|---|---|---|---|
| arena_elo_coding | Text Arena coding category, raw (not style-controlled) | 1513.97 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_elo_overall | Text Arena overall, raw (not style-controlled) | 1494.67 | Arena score (Elo scale) | [1486.14, 1503.21] | 2026-09-13 |
| Source |
| arena_elo_style_control | text_style_control / overall, latest split, revision 1880dbebff5b | 1493.01 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_business | text_style_control / industry_business_and_management_and_financial_operations, latest split, revision 1880dbebff5b | 1495.21 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_chinese | text_style_control / chinese, latest split, revision 1880dbebff5b | 1543.31 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_coding | text_style_control / coding, latest split, revision 1880dbebff5b | 1534.96 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_creative_writing | text_style_control / creative_writing, latest split, revision 1880dbebff5b | 1495.85 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_english | text_style_control / english, latest split, revision 1880dbebff5b | 1502.66 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_expert | text_style_control / expert, latest split, revision 1880dbebff5b | 1502.04 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_factuality | text_factuality / overall, latest split, revision 1880dbebff5b | 1489.99 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_hard_prompts | text_style_control / hard_prompts, latest split, revision 1880dbebff5b | 1517.19 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_industry_entertainment_sports_media | text_style_control / industry_entertainment_and_sports_and_media, latest split, revision 1880dbebff5b | 1465.53 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_industry_mathematical | text_style_control / industry_mathematical, latest split, revision 1880dbebff5b | 1519.73 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_industry_software_it_services | text_style_control / industry_software_and_it_services, latest split, revision 1880dbebff5b | 1518.01 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_instruction_following | text_style_control / instruction_following, latest split, revision 1880dbebff5b | 1491.7 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_legal | text_style_control / industry_legal_and_government, latest split, revision 1880dbebff5b | 1482.91 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_longer_query | text_style_control / longer_query, latest split, revision 1880dbebff5b | 1508.86 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_medicine | text_style_control / industry_medicine_and_healthcare, latest split, revision 1880dbebff5b | 1498.96 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_multi_turn | text_style_control / multi_turn, latest split, revision 1880dbebff5b | 1513.3 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_non_english | text_style_control / non_english, latest split, revision 1880dbebff5b | 1478.34 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_russian | text_style_control / russian, latest split, revision 1880dbebff5b | 1494.62 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_science | text_style_control / industry_life_and_physical_and_social_science, latest split, revision 1880dbebff5b | 1506.01 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_sc_writing | text_style_control / industry_writing_and_literature_and_language, latest split, revision 1880dbebff5b | 1499.8 | Arena score (Elo scale) | Unavailable | 2026-09-13 |
| Source |
| arena_webdev | webdev / overall, latest split, revision 1880dbebff5b | 1583.75 | Arena score (Elo scale) | Unavailable | 2026-09-23 |
| Source |
Missing facts for Gemini 3.8 Flash
model.hardware_fit_indeterminate: unknownmodel.languages: unknownmodel.parameters_total: unknownorigin.base_lineage: not_disclosedorigin.weights_hosting: not_disclosedoffering.api_model_id: unknownoffering.attestation.soc2: not_disclosedoffering.router_slug: unknownoffering.speed.throughput: unknownoffering.speed.time_to_first_token: unknown
What this template teaches
The gates are the same as the other tiers; only the ranking moves toward cost.
Decision dec_dec45b7d93983dd1d411f74a on public snapshot snap_05a963d2477ac2fb.
Read the full dated job answer.
The live board uses current data. This link applies the template to its full lineup.
Human lookup is free on Decide. CLI, API, and MCP access requires a key. Access and pricing.