AI code editors have quickly become a mainstay of software development, employed by tech giants such as Amazon, Microsoft, and Google.

In an interesting twist, a new study suggests that AI tools might actually be slowing experienced developers down.

Experienced developers using AI coding tools took 19% longer to complete issues than those not using generative AI assistance, according to a new study from Model Evaluation & Threat Research (METR).

Even after completing the tasks, participants couldn’t accurately gauge their own productivity, the study said: The average AI-assisted developers still thought their productivity had gained by 20%.

How the study was set up

METR’s study recruited 16 developers with large, open-source repositories that they had worked on for years. The developers were randomly assigned into two groups: Those allowed to use AI coding assistance and those who weren’t.

The AI-assisted coders could choose which vibe-coding tool they used. Most chose Cursor with Claude 3.5/3.7 Sonnet. Business Insider reached out to Cursor for comment.

Developers without AI spent over 10% more time actively coding, the study said. The AI-assisted coders spent over 20% more time reviewing AI outputs, prompting AI, waiting on AI, or being idle.

A ‘really surprising’ result — but it’s important to remember how fast AI tools are progressing

METR researcher Nate Rush told BI he uses an AI code editor every day. While he didn’t make a formal prediction about the study’s results, Rush said he jotted down positive productivity figures he expected the study to reach. He remains surprised by the negative end result — and cautions against taking it out of context.

“Much of what we see is the specificity of our setting,” Rush said, explaining that developers without the participants’ 5-10 years of expertise would likely see different results. “But the fact that we found any slowdown at all was really surprising.”

Steve Newman, serial entrepreneur and cofounder of Google Docs, described the findings in a Substack post as “too bad to be true,” but after more careful analysis of the study and its methodology, he found the study credible.

“This study doesn’t expose AI coding tools as a fraud, but it does remind us that they have important limitations (for now, at least),” Newman wrote.

The METR researchers said they found evidence for multiple contributors to the productivity slowdown. Over-optimism was one likely factor: Before completing the tasks, developers predicted AI would decrease implementation time by 24%.

For skilled developers, it may still be quicker to do what you know well. The METR study found that AI-assisted participants slowed down on the issues they were more familiar with. They also reported that their level of experience made it more difficult for AI to help them.

AI also may not be reliable enough yet to produce clean and accurate code. AI-assisted developers in the study accepted less than 44% of the generated code, and spent 9% of their time cleaning AI outputs.

Ruben Bloom, one of the study’s developers, posted a reaction thread on X. Coding assistants have developed considerably since he participated in February.

“I think if the result is valid at this point in time, that’s one thing, I think if people are citing in another 3 months’ time, they’ll be making a mistake,” Bloom wrote.

METR’s Rush acknowledges that the 19% slowdown is a “point-in-time measurement” and that he’d like to study the figure over time. Rush stands by the study’s takeaway that AI productivity gains may be more individualized than expected.

“A number of developers told me this really interesting anecdote, which is, ‘Knowing this information, I feel this desire to use AI more judiciously,'” Rush said. “On an individual level, these developers know their actual productivity impact. They can make more informed decisions.”

HSBC has become the first UK bank to leave the global banking industry’s net zero target-setting group, as campaigners warned it was a “troubling” sign over the lender’s commitment to tackling the climate crisis.

The move risks triggering further departures from the Net Zero Banking Alliance (NZBA) by UK banks, in a fresh blow to international climate coordination efforts.

HSBC’s decision follows a wave of exits by big US banks in the run-up to Donald Trump’s inauguration in January. His return to the White House has spurred a climate backlash as he pushes for higher production of oil and gas.

HSBC was a founding member of the NZBA at its launch in 2021, with the bank’s then chief executive, Noel Quinn, saying it was vital to “establish a robust and transparent framework for monitoring progress” towards net zero carbon-emission targets.

“We want to set that standard for the banking industry. Industry-wide collaboration is essential in achieving that goal,” Quinn said.

Convened by the UN environment programme’s finance initiative but led by banks, the NZBA commits members to aligning their lending, investment and capital markets activities with net zero greenhouse-gas emissions by 2050 or earlier.

Six of the largest banks in the US – JP Morgan, Citigroup, Bank of America, Morgan Stanley, Wells Fargo and Goldman Sachs – left the NZBA after Trump was elected.

UK lenders including Barclays, Lloyds, NatWest, Standard Chartered and Nationwide were still listed as members as of Friday afternoon.

In February HSBC announced it was delaying key parts of its climate goals by 20 years and watering down environmental targets in a new long-term bonus plan for its chief executive, Georges Elhedery, who took over last year.

The climate campaign group ShareAction condemned the move, saying it was “yet another troubling signal around the bank’s commitment to addressing the climate crisis”.

Jeanne Martin, ShareAction’s co-director of corporate engagement, said: “It sends a counterproductive message to governments and companies, despite the multiplying financial risks of global heating and the heatwaves, floods and extreme weather it will bring.

“Investors will be watching closely how this backsliding move will translate into its disclosures and policies.”

HSBC said in a statement: “We recognise the role the Net Zero Banking Alliance has played in developing guiding frameworks to help banks establish their initial target-setting approach.

“With this foundation in place, we have decided to withdraw from the NZBA as we work towards updating and implementing our own net zero transition plan.

“We remain resolutely focused on supporting our customers to finance their transition objectives and on making progress towards our net zero by 2050 ambition.”

Just days before Nvidia stormed past $4 trillion market cap, setting off another frenzied rally around artificial intelligence (AI)-linked stocks, a quieter, less meme-able tech giant, Cisco Systems, was building a case for relevance, led by its top brass, Chuck Robbins and Jeetu Patel, in the heart of Mumbai. Long seen as a legacy stalwart of the dotcom era, Cisco today trades at a market cap of $272 billion, a far cry from its 2000 peak of $500 billion. But for its CEO Chuck Robbins and president and chief product officer Jeetu Patel, the story has only begun to play out now.