ModelRefs / VQA (Visual Question Answering) — AI Glossary
VQA (Visual Question Answering) — AI Glossary
A benchmark asking models to answer open-ended natural language questions about images, requiring joint vision-language understanding.
Overview
VQA v2 (Goyal et al. 2017) contains 1.1M questions on MS COCO images, balanced to reduce language prior exploitation. Accuracy on open-ended VQA v2 has progressed from 65% (early fusion models) to 85%+ for GPT-4V and Gemini. Foundation for evaluating multimodal reasoning capabilities.
Reference details
| Topic | evaluation |
|---|---|
| Last reviewed | 2026-06-24 |
Related terms
How it works
- Each question is answered independently by ten human annotators, so the ground truth is a distribution of short answers rather than a single string.
- A model's answer scores the number of annotators who gave it divided by three, capped at one — so matching three of the ten is already full credit.
- That rule exists because open-ended visual questions have several correct phrasings, and requiring unanimity would penalise a right answer for being worded differently.
- It also makes answer normalisation load-bearing: articles, plurals and number words are rewritten to a canonical form before matching, and a model whose phrasing escapes that normalisation loses credit it earned.
- The dataset is built in complementary pairs — the same question asked of two images with different answers — so a model ignoring the image cannot exploit the answer prior.
- Those pairs are the structural fix for a measurement problem rather than a difficulty increase, and the general form of the lesson is that an evaluation a text-only model passes is measuring the language prior.
Example: Balanced pairs, and the prior they were built to break
Early visual question answering could be gamed without looking at the image: “what colour is the banana” is answered correctly by a model that has learned bananas are yellow. The fix was structural — for each question, include a second image where the same question has a different answer. Now a model that ignores the image is right about half the time on that pair instead of nearly always. That construction is the benchmark's real contribution, and it generalises: whenever a multimodal eval is easy for a text-only model, the eval is measuring the language prior.
Commonly confused with
Visual question answering is a task, and the dataset of that name is one instance of it. Chart and document question answering are separate benchmarks with different failure modes — reading a value off an axis is not the same skill as recognising an object, and a model can be strong at one and weak at the other.
When to use it
Reach for it when:
- Checking that a multimodal model actually conditions on the image
- Regression testing a vision encoder or projection layer change
- As a floor check, alongside document and chart benchmarks that probe different skills
Reach for something else when:
- As a summary of multimodal ability — the question distribution is narrow
- Judging OCR or dense-text reading, which it barely exercises
- Comparing figures without the answer-normalisation rules, which move results materially
Primary source
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Frequently asked questions
What is VQA (Visual Question Answering)?
A benchmark asking models to answer open-ended natural language questions about images, requiring joint vision-language understanding.
What concepts are related to VQA (Visual Question Answering)?
Closely related concepts include mmmu, chartqa, multimodal architecture.