Project APE wrote 1,000 economics papers in Claude Code in four months, and its audit faults every one
The University of Zurich project publishes every paper, script and failure. Its loop ran with no human input, on real public data, with eleven other models checking the work.
Project APE, for Autonomous Policy Evaluation, is run by the Social Catalyst Lab at the University of Zurich and led by David Yanagizawa-Drott. It describes itself as “an experiment testing whether an autonomous system can reliably generate, replicate, and verify empirical policy research”, and it keeps the papers, code, data and failures public.
Claude Code runs every stage from the idea to the revision
| Stage | Who does it | The rule |
|---|---|---|
| Idea | Claude Code | A policy question with a credible identification strategy |
| Data | Claude Code | Real data from public APIs such as Census, BLS and FRED. If the data is missing, the agent changes the question. Simulated data means automatic rejection. |
| Estimation | Claude Code, in R | Difference-in-differences, regression discontinuity and other causal designs, with established packages |
| Manuscript | Claude Code | LaTeX, with the tables and figures |
| Review | Other models | Four advisers check for fatal errors and three must pass. Then exhibits, prose and three parallel referees. |
| Integrity | Automated | Code is scanned for fabricated data and hard-coded results, then rerun to see that it reproduces the paper |
| Ranking | Gemini 3.1 Flash Lite | Head-to-head against published AER and AEJ papers, each pair judged twice with the order swapped |
Papers from January 2026 were written on Claude Opus 4.5 and later ones on Opus 4.6. From March some were written together with Codex. The judge comes from a different company on purpose: the methodology page says a non-Anthropic model was chosen “to avoid potential self-preference bias”.
Every paper ships as a folder a stranger can rerun
The public archive holds one folder per paper. The production code that drives the agents is not in it.
apep_XXXX/
├── paper.pdf # Final PDF
├── paper.tex # LaTeX source
├── metadata.json # Self-describing metadata
├── initial_plan.md # Original research plan (never modified)
├── research_plan.md # Final research plan (evolved version)
├── code/ # R analysis scripts
├── data/ # Replication data
└── figures/ # Generated figures
The file initial_plan.md is the pre-registration. The archive’s README says each research plan is committed before the data analysis and that “git timestamps prove sequence”. The archive had 435 stars and 93 forks on GitHub on 11 October 2026.
The lab stopped at 1,000 papers and audited them
In a separate sample of 100 unaltered papers, human reviewers agreed that 97% of the findings reported by the chosen verifier were real errors or defects. From that verifier’s reports the project estimates that every one of the 1,000 papers contains errors or defects, often several, some of them severe. Humans did not check all 1,000.
The tournament’s judge saw only the PDF. The site calls its ranking “a noisy triage signal” and says it is not peer review. Across all matches the judge’s ratings give a human paper an 88.1% chance of beating an APE paper, over 990 APE papers and 43 human papers. A separate study of 912 APE papers put most of that gap on the idea.
Three of its rules transfer to a finance pipeline unchanged
APE pulls only from public APIs, so no data license is involved. A finance version on CRSP or Compustat has to clear the license terms first. The SEC and FRED are open to the same loop today.
Sources
- Project APE, Social Catalyst Lab ape.socialcatalystlab.org
- Project APE, methodology ape.socialcatalystlab.org
- GitHub, SocialCatalystLab/ape-papers github.com