AI-Generated Code Quality: Why It Passes Review and Fails in Production
What a vendor survey and the independent studies show, and how to govern AI-written code
This article distinguishes documented capabilities from forecasts and hypothetical outcomes. The word superintelligence does not currently refer to a universally agreed, independently verified benchmark.
On this page
Is AI-generated code lower quality than human code?
Direct Summary
Surveyed technology leaders rate AI-generated code higher than human code at review, yet most also report more production incidents. A vendor-commissioned survey of 200 US leaders shows the pattern. Independent studies agree on direction, not size, and none proves AI causes the incidents.
Technical Nuance & Operational Realities
The headline numbers come from a survey, so they describe what leaders believe and report, not what production systems logged. New Relic commissioned the survey from Hanover Research, and New Relic sells observability software. Treat every survey percentage on this page as a self-report.
The independent evidence measures different things. CodeRabbit counted review findings per pull request, METR timed developers on real tasks, DORA surveyed professionals about delivery performance, and Veracode and a USENIX Security paper tested what models produce in controlled tasks. Each supports a narrow conclusion. None measures, across many organizations, whether AI-written code causes more outages than human-written code.
This matters for superintelligence because the pattern is a small, observable case of the oversight problem: systems that produce work faster than people can check it. It does not show that superintelligence is near. Google's chief executive wrote that 75% of new code at Google is AI-generated and approved by engineers, so verification, not authorship, is where human effort now goes. Our analysis: the practical response (tests, telemetry, sandboxing, independent evaluation) is a working form of what alignment researchers call scalable oversight, covered in our guide to alignment theories.
What the evidence shows
What the New Relic survey measured
New Relic's 2026 State of AI Coding report, dated June 2026, surveyed 200 US-based technology decision-makers at manager level or above. Hanover Research ran the survey and New Relic commissioned it. The sample leans toward large organizations and a few industries, and the questionnaire and raw data are not public.
| Finding in the report | Share of respondents |
|---|---|
| Rate AI-generated code higher quality than human code at review (33% "much higher", 61% "somewhat higher") | 94% |
| Place weekly AI-generated or significantly refactored code in the 51% to 75% band | 67% |
| Say their teams often trust AI code enough to ship it without line-by-line manual verification | 62% |
| Report more production incidents over the past 12 months | 78% |
| Report more senior-engineer time spent fixing code over the past 12 months | 86% |
| Report at least one production failure tied to AI-generated code in the past six months | 82% |
| Say at least a quarter of AI-generated code needs significant rework | 74% |
Read the table as perceptions. The 67% row is the share of leaders who chose a band, not the share of code that is AI-written. The 62% row comes from the report's text, which says "often"; one chart labels it "often or always". The report does not show that AI caused the incidents. Incident counts can also rise simply because teams ship more code and more services.
What independent studies add
| Study | Design | Finding | What it does not show |
|---|---|---|---|
| CodeRabbit, State of AI vs Human Code Generation (Dec 2025) | 470 open-source pull requests: 320 AI-co-authored, 150 human-only | 10.83 findings per AI-co-authored PR versus 6.45, about 1.7 times; CodeRabbit reports 1.4 to 1.7 times for critical and major findings | Findings flagged at review by CodeRabbit's own tool, not runtime incidents. CodeRabbit sells AI code review |
| METR randomized trial (July 2025) | 16 experienced open-source developers, 246 tasks in their own repositories | Tasks took 19% longer with AI; developers expected a 24% speedup and afterwards believed they had been about 20% faster | Early-2025 tools and a small sample |
| METR follow-up (Feb 2026) | 57 developers, 143 repositories, 800+ tasks | Time change of -18% for returning developers and -4% for new ones (negative means faster); both 95% intervals include zero | METR calls this "an unreliable signal", mainly because developers declined to work without AI |
| DORA 2025 (Google Cloud) | Nearly 5,000 technology professionals | 90% use AI at work; 30% report little or no trust in AI-generated code; AI adoption is positively related to throughput and negatively related to delivery stability | A survey association, not cause and effect |
| Veracode GenAI Code Security Report (2025) | More than 100 models on coding tasks | 45% of code samples failed security tests; Java had a 72% failure rate | Lab tasks, not production code |
| Spracklen et al., USENIX Security 2025 | 576,000 code samples from 16 models | 19.7% of the packages recommended overall did not exist; rates were at least 5.2% for commercial and 21.7% for open-source models | Python and JavaScript only; attackers must also register the names |
| GitHub controlled study (Nov 2024) | 202 valid submissions: 104 with Copilot, 98 without | Code with Copilot was 53.2% more likely to pass all 10 unit tests; reviewers rated readability, reliability, maintainability and conciseness 2.47% to 4.16% higher | One task, run by the tool's vendor |
The Stack Overflow 2025 Developer Survey adds the trust picture: 84% of respondents use or plan to use AI tools, and 46% distrust their accuracy compared with 33% who trust it. On the other side of the ledger, Google's Sundar Pichai wrote in April 2026 that 75% of new code at Google is AI-generated and approved by engineers, up from 50% the previous fall. That counts new code only, and Google has not said how it counts.
What the data does not show
- No causal link. None of these sources isolates AI as the cause of incidents.
- No production telemetry. The New Relic figures are survey answers, not logs, traces or incident records.
- No shared definition. "AI-generated" means something different in each survey, company statement and pull-request analysis.
- No benchmark-to-production bridge. Test scores do not predict your incident rate.
- Mixed direction. The GitHub study found quality gains in a controlled task, while CodeRabbit and DORA point the other way on review findings and stability.
How to govern AI-generated code
Our analysis, not a sourced finding: govern by risk tier, not by authorship. The same baseline applies to every change, and the gates tighten where failure is costly. The New Relic survey found no organization with a blanket ban, and nothing in the sources above supports one.
| Tier | Examples | Suggested use of AI coding | Minimum controls |
|---|---|---|---|
| 0: Throwaway | Prototypes, spikes, demos | Allowed, including vibe coding | Isolated environment; no production data or credentials |
| 1: Internal | Internal tools, scripts, dashboards | Allowed | One human review; static analysis; dependency allowlist; tests in CI |
| 2: Customer-facing | Product features, APIs | Allowed with gates | A human reads every changed line of logic; tests that fail without the change; canary release; rollback plan |
| 3: Critical | Authentication, payments, cryptography, data migrations, infrastructure code | Assistive only; no autonomous merge | Two reviewers including a code owner; threat model; staged rollout; audit trail |
Measure outcomes, not suggestions accepted
METR's developers expected a speedup and believed afterwards that they had been faster, while the measured result in 2025 was slower. Self-reports are unreliable, so track delivery outcomes and split them by whether a change was AI-assisted:
- Change failure rate: the share of deployments that need a rollback, hotfix or patch.
- Time to recover after a failed deployment.
- Rework rate: unplanned fixes to recently shipped changes.
- Escaped defects: bugs found in production per release.
- Review depth: the share of AI-assisted changes with line-by-line human review, by tier.
Verification checklist for AI-assisted changes
- The change is labelled AI-assisted and has a risk tier.
- A human has read every changed line of logic at tier 2 and above.
- New and changed paths have tests that fail without the change.
- Every new dependency exists, is on an allowlist and is pinned. Fabricated package names are a documented attack route.
- Security scanning and secret scanning pass with no suppressed findings.
- Authentication, payment, cryptography and migration changes have two approvals.
- Logs, metrics and traces exist for the new code paths.
- A rollback or feature flag can disable the change.
- Any agent credentials used were least-privilege and have expired.
At a Glance
Figures are as printed in each primary source, read on 2026-10-21. Survey rows are self-reports.
| Question | Best-supported answer today | Evidence type | Main limitation |
|---|---|---|---|
| Does AI code look better at review? | Most surveyed leaders say yes (94%) | Vendor-commissioned survey, n=200 | Perception of readable code, not defects |
| Does it cause more production problems? | Leaders report more incidents (78%) and senior fix time (86%) | Same survey | No causal test; more code can mean more incidents |
| Does it produce more review findings? | About 1.7 times more per pull request in one analysis | 470 open-source PRs, vendor tool | Findings, not outages |
| Does it make developers faster? | Unresolved | Randomized trial and follow-up | Small samples; follow-up called unreliable by METR |
| Is it secure? | Not by default | Lab tests (Veracode, USENIX) | Controlled tasks |
The table is a decision aid, not a verdict. Before relying on any figure, record its date, sample, definition of "AI-generated", and who paid for the research. If a number is unavailable or not comparable, say so instead of filling the gap.
Sources & Further Reading
Every source below was fetched on 2026-10-21 unless a row says otherwise.
| Claim | Source | Section or date |
|---|---|---|
| Survey sample, method, sponsor, and all New Relic percentages | The 2026 State of AI Coding report (PDF) | Key Findings (p.2); Methodology (p.4); Findings 01, 03, 04, 06, 08; dated 06.2026 |
| Report publication date | Introducing the State of AI Coding 2026 (New Relic) | June 10, 2026 |
| 470 pull requests, 10.83 vs 6.45 findings, about 1.7 times | State of AI vs Human Code Generation (CodeRabbit) | Dec 17, 2025; "Top 10 findings" |
| 16 developers, 246 tasks, 19% longer, expected and perceived speedup | Measuring the Impact of Early-2025 AI on Experienced Open-Source Developer Productivity (METR) | July 10, 2025 |
| 57 developers, 143 repositories, -18% and -4% estimates, "unreliable signal" | METR uplift update | Feb 24, 2026 |
| Nearly 5,000 respondents, 90% use, 30% low trust, throughput and stability relationships | Announcing the 2025 DORA Report (Google Cloud) | Sept 24, 2025 |
| More than 100 models, 45% of samples failed security tests, Java 72% | GenAI Code Security Report (Veracode) | July 30, 2025 |
| 576,000 samples, 16 models, 205,474 unique fake names, 5.2% and 21.7% rates, 19.7% overall | We Have a Package for You! (USENIX Security 2025) | Abstract; Results section of the paper |
| 75% of new code at Google AI-generated and engineer-approved | Sundar Pichai at Cloud Next '26 (Google) | Apr 22, 2026 |
| 84% use or plan to use AI tools; 46% distrust, 33% trust | 2025 Stack Overflow Developer Survey, AI | Usage and accuracy sections; undated |
| 202 submissions, 53.2% more likely to pass all unit tests | Does GitHub Copilot improve code quality? (GitHub Blog) | Nov 18, 2024, updated Feb 6, 2025 |
Left out after checking sources: the Veracode "80 tasks" count (not found on any Veracode page we could fetch); a New Relic product launch (neither the blog nor the report announces one); a critical-only 1.4 times figure for CodeRabbit (the page gives a combined critical and major range); and OpenAI's February 2026 note on SWE-bench Verified (the page blocked automated access, so we could not read it).
How we weigh evidence, and what terms like AGI and ASI mean on this site, is explained in our methodology.
Frequently asked questions
Is AI-generated code lower quality than human code?
Surveyed technology leaders rate AI-generated code higher than human code at review, yet most also report more production incidents. A vendor-commissioned survey of 200 US leaders shows the pattern. Independent studies agree on direction, not size, and none proves AI causes the incidents.
Does AI make developers faster?
The evidence is mixed. METR's 2025 randomized trial found 16 experienced open-source developers took 19% longer with AI tools, although they expected to be faster. METR's 2026 follow-up produced estimates whose intervals include zero, and METR calls them an unreliable signal.
Is AI-generated code secure?
Not by default. Veracode reported that 45% of code samples from more than 100 models failed its security tests, and a USENIX Security 2025 study found models recommend packages that do not exist. Scan AI output, check every dependency, and review security-sensitive paths by hand.
