AI Index Report 2022

The models got better at everything — including bias

Chapter 3 of the AI Index 2022 is the first edition to measure AI ethics the way the report measures accuracy: with benchmarks, metrics and citation counts. What it finds in 2021 is a scaling law nobody wanted. Larger language models set new records on technical benchmarks and simultaneously became more toxic, more stereotyped and better at memorizing the worst of their training data. Meanwhile the field studying the problem grew faster than at any point in its history. The numbers:

29% more elicited toxicity from a 280B-parameter 2021 model vs. the 117M-parameter 2018 state of the art
53authors with an industry affiliation at FAccT 2021 (2020: 31, 2018: 5) — up 71% in a year
168NeurIPS papers on fairness and bias accepted in 2021 (2015: 2)
75.4% of FAccT 2021 papers from North American institutions (2020: 70.2%)
14% of images of Black people CLIP misclassified as nonhuman — next highest was 7.6%
142English-only automated fact-checking benchmarks, against 35 in every other language combined

3.2 — Every bias metric in this chapter gets worse as models get bigger

Toxicity, stereotype score, religious bias — the 2021 results line up in the same direction. More capable models are also more capable of learning and amplifying what is in their training data, and the training data is the internet.

Toxicity scales with parameters

DeepMind’s Gopher paper, published in December 2021, is the cleanest evidence in the chapter. Holding the prompt distribution fixed and sweeping model size from 117 million to 280 billion parameters, the probability of a toxic continuation rises at every prompt-toxicity level. That single comparison is the chapter’s headline: a 280 billion parameter model developed in 2021 shows a 29% increase in elicited toxicity over a 117 million parameter model considered state of the art as of 2018. The same sweep contains a genuine consolation — larger models are also dramatically better at identifying toxic comments, with few-shot classification AUC on CivilComments climbing steadily from 44 million parameters up to 280 billion. The models that produce the problem are also the best detectors of it.

Where the toxicity comes from is measurable too. Models trained on internet text with toxic content filtered out score far lower on expected maximum toxicity than models trained on unfiltered corpora. The surprise is BookCorpus, which produces toxic text surprisingly often for a book dataset — the report attributes this to its large share of romance novels with explicit content. The prevalence of toxic content online has been estimated at just 0.1%–3%, which is precisely why the trend matters: bigger models are better at memorizing rare text.

Detoxification is not free

The obvious fix has a cost that falls unevenly. Detoxification methods — domain-adaptive pretraining (DAPT), Plug and Play Language Models (PPLM), Generative Discriminator Guided Sequence Generation (GeDi) — all raise perplexity, meaning worse language modeling, and they do it disproportionately on African American English and on text mentioning minority identities compared with white-aligned text. The likely cause is upstream of the model: human annotators are more apt to mislabel African American English as toxic, so the detoxifier learns to penalize it. Cleaning up a model’s output can quietly marginalize the voices it was supposed to protect.

Stereotypes follow the same curve

  • StereoSet measures whether a model prefers stereotypes over anti-stereotypes across gender, race, religion and profession. Stereotype score rises with model size, from 58.30 at 110 million parameters to 62.00 at 175 billion — unless interventions are taken during training to reduce learned stereotypes.
  • CrowS-Pairs contrasts historically advantaged and disadvantaged groups rather than attributes of a single group. Tested on BERT, RoBERTa and ALBERT, it inverts the capability ranking: ALBERT beats RoBERTa which beats BERT on SQuAD, GLUE and RACE, and ALBERT is the most biased of the three.
  • The religious skew is traceable to the corpus. All three models were trained on some combination of BookCorpus, English Wikipedia and scraped web text, and an audit of BookCorpus and Smashwords21 finds books on Christianity and Islam vastly outnumbering those on Sikhism, Judaism, Hinduism, Buddhism or atheism.
  • StereoSet itself is flawed, and the chapter says so: some examples fail to express a harmful stereotype, some conflate stereotypes about countries with stereotypes about race, and the whole dataset was sourced from crowdworkers located in the United States, so its values may not be universally representative.

StereoSet stereotype score, by model size

Higher means the model more often prefers a stereotype over an anti-stereotype. The curve is not perfectly monotonic — a 345 million parameter model scored 58.20, below the 340 million parameter model at 59.30, and the largest model shown here is not the most biased — but the direction across two orders of magnitude is unmistakable.

StereoSet stereotype score, by model size110M: 58.358.3110M340M: 59.359.3340M1.6B: 60.160.11.6B175B: 6262175B178B: 60.760.7178B

3.1 — We now have a lot of bias metrics. We still can’t tell if they mean anything downstream

The AI Index conducted original research to map the field, counting every fairness and bias metric cited at least once by another work. The count has grown steadily since 2018, split between two kinds of measurement that answer different questions — and the link between them is missing.

  • Benchmark datasets contain labeled data and do not change over time. They are domain-specific — StereoSet and SuperGLUE for language, ImageNet for vision — and usually measure something intrinsic to the model rather than its downstream performance on real populations. Their value is community adoption: leaderboard submissions and papers reporting the metric make progress legible for the whole field.
  • Diagnostic metrics measure the impact of a model on a downstream task, such as one population subgroup compared with another. Group fairness measures like demographic parity and equality of opportunity sit here. They are the ones that map onto real-world harm, and they are the ones we know least about publicly, because they are not attached to leaderboards that reward publishing results.
  • Both have grown at a steady rate since 2016. The unusually large crop of 2017 metrics is largely one release: the Perspective API defined seven new facets of toxicity at once — toxicity, severe toxicity, identity attack, insult, obscene, sexually explicit and threat.
  • Benchmarks are static snapshots of a specific cultural and temporal context. As the chapter puts it, a benchmark published in 2017 may not correlate to the deployment context of 2022. Some leaderboards can also be gamed, and some rest on datasets with incorrect labels or poorly defined classes.

The gap nobody has closed

The chapter’s most consequential sentence is a negative result. It is commonly assumed that de-biasing a model’s embeddings — reducing intrinsic bias — will reduce the bias that shows up in applications. It has been demonstrated that there is no reliable correlation between intrinsic bias metrics and downstream application biases. The majority of the metrics in this chapter measure intrinsic bias. So the field has built a large and growing measurement apparatus whose relationship to real-world harm remains unestablished, and the chapter says plainly that further investigation is needed.

Gender, occupation and translation

  • Winogender builds coreference sentences around occupations skewed by gender in U.S. Bureau of Labor Statistics data — cashiers are 73% women, drivers only 6%. On the SuperGLUE leaderboard, larger models do resolve gender better: coreference accuracy reaches 0.72 at 64 billion parameters and 0.71 at 280 billion, against 0.53 at 31 million. Crowdsourced human performance is 99.7%.
  • A good Winogender score does not mean a model is unbiased with respect to gender. It means this benchmark did not capture the bias.
  • WinoBias was released concurrently by a different group and is cited more often — 128 citations against Winogender’s 95 in 2021 — but Winogender’s place on the SuperGLUE leaderboard means more models get evaluated on it.
  • WinoMT combines the two datasets to test machine translation. Google Translate performs better across all eight tested languages — Arabic, English, French, German, Hebrew, Italian, Russian, Ukrainian — when the occupation conforms to a gender stereotype, and translates with the correct gender only up to 60% of the time. Microsoft Translator, Amazon Translate and SYSTRAN behave similarly.

The measurement toolbox, and what each tool can’t see

Six families of metric carry most of the chapter. Each was designed against a specific harm, and each has a documented blind spot that the chapter is careful to name.

RealToxicityPrompts + Perspective API

English prompts that measure how often a model completes them with toxic text, scored by a Google-built classifier the research community adopted wholesale.

toxicity

StereoSet

Measures whether a model prefers stereotypes and anti-stereotypes equally, across gender, race, religion and profession, alongside raw language modeling ability.

stereotypesbenchmarks

CrowS-Pairs

Contrasts historically advantaged and disadvantaged groups across nine bias attributes — and found the most capable of three models to be the most biased.

stereotypes

Winogender and WinoBias

Coreference tests built on occupations that skew by gender in U.S. labor statistics. Two teams released near-identical benchmarks at the same time.

genderbenchmarks

WinoMT

Combines Winogender and WinoBias to measure gender bias in commercial machine translation, where mistakes are costly at global scale.

gendertranslation

WEAT, SEAT, iEAT and their extensions

The association tests measure bias inside the representation itself — and they work on images and on languages other than English too.

embeddings

What NeurIPS accepted on ethics in 2021

Accepted papers in 2021, counting the main track and the matching ethics-related workshops. Every one of these lines started near zero: fairness and bias was 2 papers in 2015, privacy 1, interpretability 2. NeurIPS held its first workshop on fairness, accountability and transparency in 2014, and from 2020 has required authors to submit broader impact statements.

What NeurIPS accepted on ethics in 2021Fairness/bias: 168168Fairness/biasPrivacy: 128128PrivacyCausality: 7676CausalityExplainability: 4141Explainability

3.3 — AI ethics stopped being a side workshop. It also stopped being global

Research on fairness and transparency has exploded since 2014, with a fivefold increase in related publications at ethics-related conferences. Two things came with the growth: industry money and authorship, and a geographic concentration that got narrower, not wider, in 2021.

Industry moved in

FAccT was one of the first major conferences created to bring researchers, practitioners and policymakers together around sociotechnical analysis of algorithms, and it publishes a significant amount of work critical of contemporary AI methods — Model Cards for Model Reporting in 2019 and On the Dangers of Stochastic Parrots in 2021 both appeared there. In 2021, 53 authors listed an industry affiliation, up from 31 in 2020 and only 5 at the inaugural conference in 2018. That is 71% growth year over year, and it aligns with the wider trend of deep learning researchers moving from academia into industry labs. Industry groups still often publish with academic collaborators, but standalone industry work is rising.

The map got smaller

The majority of papers published at FAccT are written by researchers based in the United States, followed by Europe and Central Asia. From 2020 to 2021 the North American share did not fall as the field grew — it rose, from 70.2% to 75.4%. Every other region sits in the single digits or below: East Asia and Pacific 4.03%, Latin America and the Caribbean 1.61%, the Middle East and North Africa 1.21%, Sub-Saharan Africa 0.40%, and South Asia 0.00%. The field deciding what counts as fair is drawn from a narrower slice of the world each year.

What NeurIPS chose to work on

  • Papers on fairness and bias — main track titles plus fairness workshops — climbed from 2 in 2015 to 168 in 2021, with the sharp turn beginning in 2017.
  • Privacy research grew from a single paper in 2015 to 128 in 2021, covering federated learning, differential privacy and privacy in specific domains such as financial services. It peaked at 150 in 2020.
  • Causal effect and counterfactual reasoning reached 76 papers in 2021, and NeurIPS ran three workshops dedicated to causal inference that year, one devoted entirely to causality and algorithmic fairness. Counterfactual fairness formalizes the idea that a decision is fair if it would be the same had the individual belonged to a different demographic.
  • Interpretability and explainability reached 41 papers, up from 2 in 2015, with much of the recent growth in the NeurIPS main track rather than in workshops.
  • Beyond the ethics topics themselves, NeurIPS workshop papers on real-world impacts — climate, finance, healthcare, the developing world — have grown over the past six years, pointing at increased interest in AI applied to high-risk, high-impact use cases.

Automated fact-checking benchmarks, by language

There are 142 English-only benchmarks and 35 in every other language combined. The tail below Spanish is French, German and Portuguese at 2 each, then Bengali, Bulgarian, Croatian, Italian, Malayalam and Tamil at 1 each. Whatever automated fact-checking can do in 2021, it can mostly do in English.

Automated fact-checking benchmarks, by languageEnglish: 142142EnglishArabic: 1414ArabicChinese: 55ChineseHindi: 33HindiSpanish: 33Spanish

3.4 — Five questions about what models say, and what they see

Today’s state-of-the-art language models generate false information about the world, which makes them unsafe for fully automated decision making. This section measures how false, and asks whether scale helps.

Can AI check facts yet?
Partly, and mostly as an assistant rather than a replacement. Deployed systems help human fact-checkers by flagging potential false claims, surfacing previously checked similar claims, or retrieving supporting evidence. Fully automated fact-checking is still an active research area — the 2017 Fake News Challenge pushed stance detection, and in 2019 a Canadian venture capital firm put $1 million into an automated fact-checking competition. On FEVER, which requires a system to both classify a claim and extract supporting evidence from English Wikipedia, state-of-the-art performance reached 79.35 label accuracy and a 76.78 FEVER score in 2021, both rising steadily since 2018. The task is usually framed narrowly: of the fact-checking datasets surveyed, 75 binarize labels into true or false, 28 use three classes and 16 use four.
Do bigger models tell the truth more often?
The chapter cannot resolve this, and says so. TruthfulQA asks questions from health, law, finance and politics that humans often get wrong because of common misconceptions — asked what happens if you smash a mirror, GPT-3 answers that you will have seven years of bad luck. Initial multiple-choice experiments on GPT-Neo, GPT-2, T5 and GPT-3 found that larger models give more informative answers but are not necessarily more truthful. Later experiments on Gopher contradicted that: accuracy improved with model size. The likely explanation is that TruthfulQA was collected adversarially against GPT-3 175B, which would depress that family specifically. On the open-ended generation task, WebGPT and InstructGPT both become more truthful and informative as they scale; the exception is the supervised fine-tuned baseline, which underperforms with scale exactly as the TruthfulQA paper predicted.
Does citing sources make a model safer?
Possibly the opposite. WebGPT was built to improve GPT-3’s factual accuracy by searching the web for sources to cite alongside its answers, and it does outperform GPT-3. But it still struggles with out-of-distribution questions and its performance is considerably below human performance. The chapter draws the uncomfortable conclusion: because WebGPT cites sources and therefore appears more authoritative, its untruthful answers may be more harmful, since users are unlikely to open every citation and verify it. Making a model look trustworthy is not the same as making it trustworthy.
What did CLIP learn from 400 million image-text pairs?
Multimodal capability, and multimodal bias with it. CLIP learns visual concepts from natural language and can outperform the best ImageNet-trained models on a range of classification tasks. Probing it with non-human and crime-related classes added to the FairFace dataset — animal, gorilla, chimpanzee, orangutan, thief, criminal, suspicious person — produced images of Black people misclassified as nonhuman at 14%, against 7.6% for the next highest group, images of Indian people. People aged 20 and under were more likely than any other age group to be assigned crime-related classes. Probing with the Members of Congress dataset attached nanny and housekeeper to women, prisoner and mobster to men; CLIP almost exclusively associates high-status labels such as executive and doctor with men, and disproportionately attaches appearance-related labels to women. Design decisions as mundane as the similarity threshold have outsized impacts on both performance and bias.
Does that bias stay inside CLIP?
No — it gets baked into the next dataset. CLIP also learned historical bias and conspiracy theories from its internet-sourced training data: in one documented probe it assigns higher similarity to housewife with an orange jumpsuit than to the correct description for a photograph of astronaut Eileen Collins. This matters because CLIP embeddings were used to filter LAION-400M for high-quality image-text pairs, and the biases CLIP learned were shown to propagate into LAION-400M, affecting anything built on it afterwards. The language gap compounds it: CLIP can be extended to other languages by swapping in a multilingual encoder such as mBERT, but mBERT performs worse than no pretrained model at all on 30% of its 104 languages, and even for French and Spanish there are noticeable accuracy gaps in gender and age classification.

The chapter in five lines

Headline findings from Chapter 3 · Technical AI Ethics.

A 280 billion parameter model developed in 2021 shows a 29% increase in elicited toxicity over a 117 million parameter model considered the state of the art as of 2018.
— Chapter 3 · Technical AI Ethics
Research on fairness and transparency in AI has exploded since 2014, with a fivefold increase in related publications at ethics-related conferences. Researchers with industry affiliations contributed 71% more publications year over year.
— Chapter 3 · Technical AI Ethics
Experiments on CLIP showed that images of Black people were misclassified as nonhuman at over twice the rate of any other race.
— Chapter 3 · Technical AI Ethics
It has been demonstrated that there is no reliable correlation between intrinsic bias metrics and downstream application biases. Further investigation is needed.
— Chapter 3 · Technical AI Ethics
A benchmark published in 2017 may not correlate to the deployment context of 2022.
— Chapter 3 · Technical AI Ethics

Read Chapter 3 in full

Chapter 3 (sections 3.1–3.4) — the meta-analysis of fairness and bias metrics, NLP bias benchmarks, AI ethics trends at FAccT and NeurIPS, and factuality and truthfulness — with every figure and citation is free from Stanford HAI.

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