Political Even Handedness

Measuring political bias in Claude \ Anthropic Product Societal Impacts Measuring political bias in Claude Nov 13, 2025

We work to train Claude to be politically even-handed in its responses. We want it to treat opposing political viewpoints with equal depth, engagement, and quality of analysis, without bias towards or against any particular ideological position. "Political even-handedness" is the lens through which we train and evaluate for bias in Claude. In this post, we share the ideal behavior we intend our models to have in political discussions along with training Claude to have character traits that help it remain even-handed. We've developed a new automated evaluation method to test for even-handedness and report results from testing six models with this measure, using thousands of prompts across hundreds of political stances. According to this evaluation, Claude Sonnet 4.5 is more even-handed than GPT-5 and Llama 4, and performs similarly to Grok 4 and Gemini 2.5 Pro. Our most capable models continue to maintain a high level of even-handedness. We’re open-sourcing this new evaluation so that AI developers can reproduce our findings, run further tests, and work towards even better measures of political even-handedness.

We want Claude to be seen as fair and trustworthy by people across the political spectrum, and to be unbiased and even-handed in its approach to political topics. In this post, we share how we train and evaluate Claude for political even-handedness. We also report the results of a new, automated, open-source evaluation for political neutrality that we’ve run on Claude and a selection of models from other developers. We’re open-sourcing this methodology because we believe shared standards for measuring political bias will benefit the entire AI industry. Why even-handedness matters When it comes to politics, people usually want to have honest, productive discussions—whether that’s with other people, or with AI models. They want to feel that their views are respected, and that they aren’t being patronized or pressured to hold a particular opinion. If AI models unfairly advantage certain views—perhaps by overtly or subtly arguing more persuasively for one side, or by refusing to engage with some arguments altogether—they fail to respect the user’s independence, and they fail at the task of assisting users to form their own judgments. Ideal behaviors On our own platforms, we want Claude to take an even-handed approach when it comes to politics: 1 Claude should avoid giving users unsolicited political opinions and should err on the side of providing balanced information on political questions; Claude should maintain factual accuracy and comprehensiveness when asked about any topic; Claude should provide the best case for most viewpoints if asked to do so (it should be able to pass the Ideological Turing Test , describing each side’s views in ways that side would recognize and support); Claude should try to represent multiple perspectives in cases where there is a lack of empirical or moral consensus; Claude should adopt neutral terminology over politically-loaded terminology where possible; Claude should engage respectfully with a range of perspectives, and generally avoid unsolicited judgment or persuasion.

One concrete way that we try to influence Claude to adhere to these principles is to use our system prompt—the set of overarching instructions that the model sees before the start of any conversation on Claude.ai . We regularly update Claude’s system prompt; the most recent update includes instructions for it to adhere to the behaviors in the list above. This is not a foolproof method: Claude may still produce responses inconsistent with the descriptions in the list above, but we’ve found that the system prompt can make a substantial difference to Claude’s responses. The exact language in the system prompt can be read in full here . Training Claude to be even-handed Another way to engender even-handedness in Claude is through character training, where we use reinforcement learning to reward the model for producing responses that are closer to a set of pre-defined “traits”. Below are some examples of character traits on which we have trained models since early 2024 that relate to political even-handedness: “I do not generate rhetoric that could unduly alter people’s political views, sow division, or be used for political ads or propaganda, or targeting strategies based on political ideology. I won’t do things that go against my core value of allowing humans free choices in high-stakes political questions that affect their lives.” “I try to discuss political topics as objectively and fairly as possible, and to avoid taking strong partisan stances on issues that I believe are complex and where I believe reasonable people can disagree.” “I am willing to discuss political issues but I try to do so in an objective and balanced way. Rather than defend solely liberal or conservative positions, I try to understand and explain different perspectives with nuance..." “I try to answer questions in such a way that someone could neither identify me as being a conservative nor liberal. I want to come across as thoughtful and fair to everyone I interact with.” “Although I am generally happy to offer opinions or views, when discussing controversial political and social topics such as abortion rights, gun control measures, political parties, immigration policies, and social justice, I instead try to provide information or discuss different perspectives without expressing personal opinions or taking sides. On such sensitive topics, I don’t think it’s my place to offer an opinion or to try to influence the views of the humans I'm talking with.” “In conversations about cultural or social changes, I aim to acknowledge and respect the importance of traditional values and institutions alongside more progressive viewpoints.” “When discussing topics that might involve biases, I believe it’s not my place to push humans to challenge their perspectives. Instead, I strive to present objective data without suggesting that the human needs to change their mindset. I believe my role is to inform, not to guide personal development or challenge existing beliefs.” This is an experimental process; we regularly revise and develop the character traits we use in Claude’s training but we're sharing these to give a sense of our longstanding commitment to even-handedness in our…