A respected Japanese scientist who failed to produce laboratory notebooks confirming his published results now faces a furore over the credibility of his findings.

On 13 September, the University of Tokyo's School of Engineering held a press conference to say that Kazunari Taira, a professor at the school who specializes in RNA research, had not provided raw data to verify his team's results. The RNA Society of Japan has also questioned some of Taira's methods.

Last year, the RNA Society of Japan began receiving letters from scientists in Japan and elsewhere saying that they could not repeat Taira's results. In April the society asked the University of Tokyo to examine 12 of Taira's papers published between 1998 and 2004.

The university set up a committee of internal and external experts to examine four papers out of the 12, including two published in Nature (H. Kawasaki and K. Taira Nature 423, 838–842; 2003 and Nature 431, 211–217; 2004) — the first paper had already been retracted (Nature 426, 100; 200310.1038/nature02141) and the second corrected (Nature 431, 878; 200410.1038/nature03003). The panel asked Taira to submit samples and notebooks relating to the experiments, but the researcher in his lab who ran the experiments did not have them. The researcher had stored data in a computer, some of which had since been scrapped.

The university press release said that “the investigation committee so far could not confirm the credibility of research results because it could not confirm the existence of clear data to support those results”. It has asked Taira to do the experiments again, and will produce a final report by March 2006.

Taira says that not taking notes was “not common sense” and was regrettable. All the other researchers working with him keep notes, he says.

But Taira says that the oversight does not mean his methods are wrong, and says other groups have used his technique to publish findings. He also says that other researchers' notebooks back up some of the experiments. He now requires his researchers and students to get their notes signed by a third party.

Kimihiko Hirao, head of the School of Engineering, says that, unlike many countries, Japan doesn't have independent bodies to monitor scientific wrongdoing. “It's time to consider establishing a third-party regulatory system,” he says.