A special investigative panel of Japan's health and labor ministry has concluded that there was no systematic cover-up of the ministry's flawed statistics, although the office in charge made false explanations.
The ministry set up the panel of outside experts in January to examine problems linked to its monthly survey on wages and working hours.
The panel concluded the ministry had no intention to cover up the flaws. But it was forced to reexamine the matter after its work was criticized as too hasty.
The panel compiled a report on Wednesday saying the flaws began in 2004, but were not noticed until 2013, when a section chief familiar with statistics was appointed.
But the person did not make corrections, and deleted references to the flaws from a statistics survey manual.
The section chief's successor, an office chief in charge of the survey, learned about the flaws and began correcting the data last year. But that person neither publicized the correction procedure nor reported it to superiors.
The report says the office in charge, as a body, falsely said statistics surveys were being carried out correctly at meetings of outside experts in 2015 and 2016 and on other occasions.
The panel concluded that this was done at the decision of the two section chiefs.
But the panel says, as it did before, that there was no systematic cover-up, citing the fact that all successive heads of the ministry's statistics division since 2004 have denied knowing that the data were skewed.
Referring to its acknowledgment that the series of acts should not be termed a cover up, the panel said it did not see any active intention to do so.
Meanwhile, opposition lawmakers are demanding to know whether the prime minister's office played a role in the change of the survey method.
The panel says the method change was aimed at making the data more understandable for users, and describes it as statistically rational.