--- title: Your AI coding spend bought 25% more output. Duplication... description: A GitClear analysis of 623 million code changes from 2023 to 2026 found that heavy AI coding tool users gained only 25% in velocity over their own prior... canonical: https://daily.dev/posts/your-ai-coding-spend-bought-25-more-output-duplication-rose-81--ciaznaq7i twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Your AI coding spend bought 25% more output. Duplication rose 81%. | daily.dev og:description: A GitClear analysis of 623 million code changes from 2023 to 2026 found that heavy AI coding tool users gained only 25% in velocity over their own prior... og:url: https://daily.dev/posts/your-ai-coding-spend-bought-25-more-output-duplication-rose-81--ciaznaq7i og:image: https://api.daily.dev/og/posts/ciAZNAq7I.png og:image:alt: Your AI coding spend bought 25% more output. Duplication rose 81%. og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Your AI coding spend bought 25% more output. Duplication rose 81%. **[The New Stack](https://daily.dev/sources/newstack)** · 8 min read · 0 upvotes · 0 comments ## Summary A GitClear analysis of 623 million code changes from 2023 to 2026 found that heavy AI coding tool users gained only 25% in velocity over their own prior output, far from the 10x claims often cited. Meanwhile, code block duplication rose 81% and refactoring (moved code) fell from 21% to 3.8% of changed lines, signaling a shift back toward code-and-fix practices whose maintenance costs will compound over time. The teams that perform best with AI tools are the same ones that already maintained strong technical discipline before AI arrived. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How much did AI coding tools like Claude Code and Cursor actually improve developer output according to real data? Heavy AI tool users gained 25% velocity over their own prior output, far below the widely claimed 10x increases. GitClear's analysis of 623 million code changes from 2023 to 2026 found that while heavy AI users out-produce non-AI users by 4 to 10x, those teams were already outperforming peers before adopting AI tooling, so the gain isn't attributable to AI alone. _Teams deciding whether their AI coding spend is paying off can track these debates on daily.dev._ ### Has code duplication increased since developers started using AI coding assistants heavily? Yes, block duplication rose 81% across a 623-million-change dataset, climbing from 40.3 to 73.0 duplicated blocks per million changed lines between 2023 and 2026. Over the same period, moved code (a signature of refactoring) fell from 21% of changed lines in 2022 to just 3.8% in 2026, and developers now copy-paste roughly five times more often than they refactor, versus a two-to-one preference for refactoring before AI. _Developers weighing code quality risks from AI-assisted coding can follow this data on daily.dev._ ## Similar posts on daily.dev - [AI Productivity Divide: Are Some Devs 5x Faster?](https://daily.dev/posts/ai-productivity-divide-are-some-devs-5x-faster--u3hr2lfpx) · Docker · 0 upvotes · 0 comments --- Tags: [#productivity](https://daily.dev/tags/productivity), [#ai-coding](https://daily.dev/tags/ai-coding), [#technical-debt](https://daily.dev/tags/technical-debt) [View this post on daily.dev](https://daily.dev/posts/your-ai-coding-spend-bought-25-more-output-duplication-rose-81--ciaznaq7i) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Your AI coding spend bought 25% more output. Duplication rose 81%.","url":"https://daily.dev/posts/your-ai-coding-spend-bought-25-more-output-duplication-rose-81--ciaznaq7i","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/your-ai-coding-spend-bought-25-more-output-duplication-rose-81--ciaznaq7i"},"datePublished":"2026-09-14T14:43:48.182Z","dateModified":"2026-09-15T06:06:12.749Z","description":"A GitClear analysis of 623 million code changes from 2023 to 2026 found that heavy AI coding tool users gained only 25% in velocity over their own prior...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/de55b9ba29d1e94b49529115429c8665?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/de55b9ba29d1e94b49529115429c8665?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"The New Stack","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"The New Stack","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/newstack","url":"https://daily.dev/sources/newstack"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/your-ai-coding-spend-bought-25-more-output-duplication-rose-81--ciaznaq7i","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"productivity,ai-coding,technical-debt","timeRequired":"PT8M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"The New Stack","item":"https://daily.dev/sources/newstack"},{"@type":"ListItem","position":3,"name":"Your AI coding spend bought 25% more output. Duplication rose 81%."}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/your-ai-coding-spend-bought-25-more-output-duplication-rose-81--ciaznaq7i#faq","mainEntity":[{"@type":"Question","name":"How much did AI coding tools like Claude Code and Cursor actually improve developer output according to real data?","acceptedAnswer":{"@type":"Answer","text":"Heavy AI tool users gained 25% velocity over their own prior output, far below the widely claimed 10x increases. GitClear's analysis of 623 million code changes from 2023 to 2026 found that while heavy AI users out-produce non-AI users by 4 to 10x, those teams were already outperforming peers before adopting AI tooling, so the gain isn't attributable to AI alone. Teams deciding whether their AI coding spend is paying off can track these debates on daily.dev."}},{"@type":"Question","name":"Has code duplication increased since developers started using AI coding assistants heavily?","acceptedAnswer":{"@type":"Answer","text":"Yes, block duplication rose 81% across a 623-million-change dataset, climbing from 40.3 to 73.0 duplicated blocks per million changed lines between 2023 and 2026. Over the same period, moved code (a signature of refactoring) fell from 21% of changed lines in 2022 to just 3.8% in 2026, and developers now copy-paste roughly five times more often than they refactor, versus a two-to-one preference for refactoring before AI. Developers weighing code quality risks from AI-assisted coding can follow this data on daily.dev."}}]} ```