trailMETR's 2025 sample of 246 completed issues from 16 developers gave sufficient statistical power to detect AI's effect on developer productivity.
Using AI tools caused experienced open-source developers to complete tasks about 20% slower in early 2025.
Issue-level randomization made METR's 246 completed issues, not its 16 developers, the effective sample for estimating the AI slowdown.
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METR's measured AI slowdown remained statistically significant when accounting for developer-level clustering.
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The METR study had sufficient statistical power to detect a productivity slowdown but insufficient power to estimate its magnitude precisely.
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METR's 2025 sample of 246 completed issues from 16 developers gave sufficient statistical power to detect AI's effect on developer productivity.
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1depended on by
this rests on ↓
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