TL;DR
Ask an LLM to flag toxic comments and it reacts to second-person address ("you," "your"), not just to rudeness. The model sees the pronoun and leans toward the "toxic" label. That one habit warps every conclusion people draw from those labels.
Here's how it goes wrong in practice. "I recommend you also read this awesome article" gets labeled toxic, while "I recommend they also read…" sails through as fine. Among comments humans rate as non-toxic, Claude Haiku flags 12% of those with no "you" and 51% of those with four or more. Deeper in a thread, people address each other directly more often, so the model "discovers" that discussions spiral into toxicity as they go deeper. Human labels show no such spiral, if anything a slight decline. The model manufactures a pattern that isn't in the data.
What helps and what doesn't. Rewriting "you" into the third person wipes out two-thirds of the fake rise. What doesn't help: showing the model the parent comment (the fake rise actually grows), matching the flag rate to the human one, or optimizing for "agreement with humans" (Cohen's κ). Good agreement with humans does not guarantee a correct conclusion. The only reliable move is checking the final conclusion against a sample of human labels.
Want this for your own case? Apply this study to your task: AI adapts its method to what you are working on and writes the prompt.
Method Blueprint (auditing an LLM labeler)
STEP 1: Label the corpus with the LLM → "toxic / not toxic" flags
STEP 2: Take the subset humans labeled "non-toxic" (placebo group)
→ check the LLM flag rate by number of "you"s and by thread depth
(flags rising with "you" and depth = bias)
STEP 3: Rewrite "you" → third person, relabel
→ did the rise disappear? then the pronoun is the cause
STEP 4: Check the final conclusion (not "labeling accuracy") against human labels
on a random sample (hundreds to thousands)
Steps 1–3 are plain requests to the model. Step 4 needs human annotators. The paper automates it with a tool called Threadsafe, which you'd have to implement in code.
Example in Practice
Task: A media analyst (say, at a tech outlet like TechCrunch or a community like Hacker News) wants to test the popular belief that "the deeper a comment thread goes, the more toxic it gets." They've exported 20,000 comments and want an LLM to label them. This is where the method shines: a conclusion about a pattern built from mass labeling. It won't help you judge a single comment.
Prompt (step 3: is the pronoun to blame?):
Below is a comment from a Hacker News discussion. Rewrite it so that:
— every way of addressing the other person ("you/your/yours/yourself") is replaced with the third person
("he", "they", "the author", "the other commenter");
— the meaning, tone, harshness and insults stay exactly the same;
— nothing is softened and nothing is added.
Return only the rewritten text.
Comment: "Did you even read the article? Your conclusion doesn't follow from your own numbers."
Then both versions (original and rewritten) go through labeling with the exact same toxicity question. After that, you compare flag rates by thread depth.
Result: The model returns the comment rewritten in the third person with its bite intact. After two labeling runs, the analyst sees whether the "toxicity rises with depth" effect dropped. If it dropped noticeably, a big chunk of the "escalation" was the model reacting to "you." Exact numbers depend on the corpus. In the paper, on English news comments, the fake rise shrank by two-thirds.
Why It Works
The weakness. An LLM judges a comment by surface cues: addressing someone directly often travels with complaints, arguments and insults. The model ties "you" to toxicity even when it's just "you could try…". The error is tied to the structure of the conversation: the deeper the reply, the more likely it's aimed at a specific person. So instead of washing out as noise, it creates a fake trend.
Why the usual checks miss it. Agreement with humans is computed over all comments at once. It doesn't show where the model is wrong: at the root of threads or deep inside them. Two models with the same κ can reach opposite conclusions. In the paper, the models that agreed with humans best (Claude) distorted the escalation the most.
What the method exploits. Models are good at rewriting text while preserving meaning. That lets you run a control experiment: strip out "you" and see whether the effect vanishes. If it does, the pronoun is the culprit. It's a standard causal check, and you can run it with a prompt.
Control knobs: - What counts as placebo. Take comments humans have already called non-toxic. Any rise in model flags on them that tracks depth or "you" is false positives. - What to swap out. Instead of "you," you can test other surface cues: ALL CAPS, exclamation marks, profanity inside quotes, brand names. - Size of the human sample. In the paper, a thousand human labels was already enough to debunk Haiku's fake rise. Hundreds give a rough check; thousands give a solid one.
Prompt Template
Step 3 (neutralizing direct address). This is my applied build based on the authors' description of the experiment:
Rewrite the comment, replacing every way of addressing the other person
({address_forms}) with the third person ({replacements}).
Preserve: meaning, tone, harshness, insults, punctuation.
Do not soften, add or explain anything.
Return only the text.
Comment: "{text}"
Steps 1 and 3 (the toxicity question, following the authors' description of their "main prompt," four answer levels):
Rate the comment on this scale: very toxic / toxic / hard to say / not toxic.
Consider toxic any rude, disrespectful or unreasonable text
that could make someone want to leave the discussion.
Return only one of the four labels.
Comment: "{text}"
What to fill in: {address_forms} (for English: "you, your, yours, yourself, y'all…"), {replacements} ("he/she/they, the author, the other commenter") and {text} (the comment).
Limitations
⚠️ English only: The experiments used English texts (Civil Comments, Reddit, Gab, Wikipedia). Languages with a formal/informal "you" split (German du/Sie, Spanish tú/usted, French tu/vous), dropped subjects and verb-based address were not tested. The effect may differ there, especially where the formal "you" signals politeness.
⚠️ The pronoun fix is partial: Rewriting removes two-thirds of the fake rise across a whole corpus and all of it within a single thread. When address appears in both the comment and its parent, only about a quarter goes away. It's a diagnostic tool, not a cure.
⚠️ Context doesn't fix it: Showing the parent comment increased the fake rise instead of reducing it. Don't count on "I'll give the model the whole thread and it'll figure it out."
⚠️ Chatbot conversations: No bias was found in human–chatbot dialogues. The effect applies to comments between people.
⚠️ Full protection needs humans and code: The Threadsafe method (human labeling on a smart sampling plan + correcting the predictions) can't be run with a prompt. Without a human sample, you're left with diagnostics and caution in your conclusions.
⚠️ No proven "magic instruction": The authors didn't test a line like "addressing someone as 'you' is not toxic in itself." That's a hypothesis you'll need to test yourself.
How They Studied It
The team took 1.25M news comments (Civil Comments) with crowd labels. Each comment was rated by several people, and the "gold" label came from a vote. They tested seven LLMs (Claude Haiku and Sonnet, plus five open models) and 14 classifier setups, including a replacement for the soon-to-be-shut-down Perspective API.
The idea was to compare not accuracy on individual comments but patterns: does toxicity rise with reply depth, with thread size, is it contagious. With human labels, toxicity dips slightly with depth (−0.12 pp per level); with Haiku, it rises (+0.93). To find the cause, the authors looked only at comments humans consider non-toxic (a placebo statistic) and saw flags rise along with the number of "you"s. A single human annotator shows almost no such rise (5.9% → 10.0%, versus 12% → 51% for Haiku).
Then they tested the hypothesis causally: they rewrote "you" into the third person, and two-thirds of the fake rise disappeared. They also checked that showing the parent comment doesn't help, that matching the flag rate doesn't help, and that a "standard error correction" doubles the fake rise (+2.02). It turned out that agreement with humans guarantees nothing: a model with κ = 0.9 could in theory produce any law from −1.30 to +1.65.
The "contagiousness" of toxicity also depends on the reference: labeled by all raters, the coefficient is 2.39; by a single rater, 1.63. The practical takeaway: results built on LLM labels without a human check can't be treated as patterns about people.
Original from the Paper
Example from the paper (verbatim):
Claude Haiku calls the reply
“I recommend you also read this awesome article” toxic
and “I recommend they also read this awesome article” not toxic
Context: The authors used this pair to show that a single pronoun flips the model's verdict.
Adaptations and Extrapolations
💡 Adaptation: auditing an LLM judge on any "noise" cue. The same trick works when an LLM rates reviews, support tickets or employee replies. Take a sample humans consider "fine" and check whether the share of "bad" ratings rises along with a surface cue (length, addressing someone as "you," the word "urgent," exclamation marks). If it does, the model is reacting to the cue, not the substance.
Here are 30 support tickets I marked as "normal." The judge model put some of them in the "aggressive" bucket. Find which surface features (addressing the agent as "you," exclamation marks, the words "I demand/urgent," length) show up more often among the mislabeled ones than among the rest. Give me a table: feature → share among mislabeled → share among the rest.
🔧 Technique: add a control run. For any mass labeling job, add a second run on the same texts with the suspicious cue removed. The gap between the runs is your estimate of that cue's influence. It's cheaper than digging through errors by hand.
Resources
- Paper: "You" Is Not Toxic: How LLM Labelers Rewrite the Web's Conversation Laws
- Authors: Liang Yue, Eric A. Vance, University of Colorado Boulder
- Code, labels and prompts: https://github.com/liyu2195/you-is-not-toxic
- Datasets mentioned: Civil Comments, CAD (Contextual Abuse Dataset), Qian et al. (Reddit, Gab), CGA-Wiki (Conversations Gone Awry), BAD (Bot-Adversarial Dialogue)
- Tools compared: Perspective API (Google, being shut down), Detoxify, PPI++, DSL