Outspoken chief economist Paul Romer is leaving the World Bank “effective immediately” after just 15 months on the job, the bank’s president told staff on Wednesday in an internal announcement seen by the Financial Times.

Mr Romer, one of the US’s most celebrated economists, had been engaged in a running battle with staff economists at the bank almost since his high-profile arrival in October 2016. Areas of dispute have included everything from Mr Romer’s diktats on grammar and brevity in reports to serious questions about methodology.

In angry email exchanges in recent months, Mr Romer has railed against what he said was the use of “obviously fabricated data”, “shameless self-promotion” by colleagues and an “Internal Justice Bureau” that prevents change.

Some inside the bank, meanwhile, were upset by what they saw as his abrasive nature. Within a year, he had been stripped of his managerial responsibilities and in recent months, he had been operating alone out of an office on a different floor from the bank’s research department.

In a message to staff sent on Wednesday, Jim Yong Kim, the World Bank’s president, said Mr Romer had told him he had decided to step down and return to his position as a professor at New York University.

“Paul is an accomplished economist and insightful individual, and we have had many good discussions on geopolitical issues, urbanisation, and the future of work. I appreciated Paul’s frankness and honesty, and I know he regrets the circumstances of his departure,” Mr Kim said.

I've never in my professional life encountered professional economists who say so many things that are easy to check and turn out not to be true

Those circumstances included a recent interview with The Wall Street Journal in which he railed against the methodology used in the World Bank’s high-profile annual “Doing Business” rankings and accused bank staff of manipulating the data for political reasons. That move, according to people in the bank, violated staff policy.

Mr Romer, who declined to comment on Wednesday, later recanted, writing on his personal blog: “This was not what I meant to say or thought I said. I have not seen any sign of manipulation of the numbers published in Doing Business report or in any other Bank report.”

But Mr Romer’s battles were far broader. He was considering leaving the bank before giving the interview to the Journal and had begun telling people privately that he was disillusioned with the World Bank’s research and his inability to bring about change, according to emails seen by the Financial Times and people close to the situation.

Some outside the bank saw Mr Romer’s comments as light-hearted. He upset staff last year when he spoke out against what he saw as the excessive use of the word “and” in internal reports.

But many of the battles were divisive and hard-fought, according to people familiar with the situation.

As chief economist, he unsuccessfully campaigned to have a number of senior department heads removed, clashing eventually with the bank’s human resources department.

One of his gripes was with internal bank resistance to using outside data to measure educational attainment in developing countries in Africa following the bank’s publication last year of a report in which it raised questions about the longstanding focus by aid agencies on school attendance rather than achievement.

In one angry exchange with a dozen other bank economists in October last year, regarding growth models in the bank’s individual country analyses, Mr Romer sharply criticised the way the bank handled its economic reports and accused colleagues of “shameless self-promotion”.

“I've never in my professional life encountered professional economists who say so many things that are easy to check and turn out not to be true,” he said in one email seen by the FT. “Imagine a field of science in which people publish research papers with data that are obviously fabricated.

“When someone points this out, the Internal Justice Bureau steps in [and] says that the concerns do not meet the burden of proof required for them to take action. Nothing happens. So in this equilibrium, it is perfectly rational to fake the data without even bothering to hide what is going on.”

He went on: “There is no way to bootstrap this field back to a state in which people put effort into maintaining a reputation as someone who is a source of reliable information. Once no one cares about reputation, why should anyone invest in reputation? As a general matter, I’m not sure about how to escape from this kind of equilibrium.”

Mr Romer on Thursday wrote on his personal blog that the email quoted by the FT had been a “thought experiment”. He wrote: “I am not aware of a single instance in which someone at the bank published fabricated data, most certainly not ‘obviously fabricated’ data.”.

But he also hinted at his concern with the bank and the debate he provoked. “In the spirit of continuous improvement, every organisation should aspire to do better,” he wrote. “At this point, any discussion about how the World Bank can do better should take place internally, not via the press, blogs or social media.”

In response to a request for comment, Shanta Devarajan, who took over management of the bank’s economic research arm after Mr Romer’s sidelining last year, said: “We stand by the quality and accuracy of our research and data, and the professionalism of our staff.”

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