Photo/Illutration A document distributed by infrastructure ministry officials to prefectural government officials shows how to compile construction contract figures for companies late in submitting reports. (Yosuke Fukudome)

Although some Cabinet ministers have downplayed the dodgy collection of construction contract data, their value was artificially increased by about 4 trillion yen ($35 billion), or 5 percent, in fiscal 2020, according to Asahi Shimbun calculations.

The inflated figure for fiscal 2020 was likely much smaller than those of previous years.

The practice of “double counting” of construction contracts by local government officials on the instructions of infrastructure ministry bureaucrats had been in place since April 2013 and was conducted on a large scale until 2019.

The Board of Audit raised questions about the statistic gathering in late 2019, and infrastructure ministry officials instructed the prefectural government officials who were in charge of collating the statistics to stop the double counting.

Infrastructure ministry officials in Tokyo continued the double counting, but on a smaller scale.

The ministry released two sets of figures for fiscal 2020: one that included the double counting and one that was based on the raw data before double counting was conducted.

The Asahi calculated the inflated amount based on those figures. Statistics experts were consulted about the calculations.

Takahiro Tsuchiya, a professor of statistical analysis at Yokohama City University who was involved in establishing how samples were to be extracted when the construction contract statistics were first collected, said, “While there may be some error from the actual (inflated) figure, the reasoning behind the calculation is reasonable.”

Hiroe Tsubaki, director-general of the Institute of Statistical Mathematics who also chairs the Statistics Committee under the internal affairs ministry, said, “The assumptions for the calculation are reasonable and a rough ballpark figure was reached.”

The double counting was conducted when construction companies failed to meet the deadline for submitting monthly reports to the local officials.

The average figure for companies that did submit reports was used instead of zero for those tardy companies.

When these companies did submit reports covering a number of months, those figures were combined as the figure for the month the reports were submitted, leading to the double counting.

Daishiro Yamagiwa, the state minister in charge of economic revitalization, said at the Jan. 24 Lower House Budget Committee session that the inflated construction contract figure had only a minor effect on calculating GDP because many other numbers are used to come up with that key economic statistic.

But Tetsuo Saito, the infrastructure minister, admitted at the same committee session that his statement in December that figures had been properly revised after January 2020 “may not have totally accurate.”

During the extraordinary Diet session in December, Prime Minister Fumio Kishida also said the statistics were correctly revised after January 2020 and emphasized there was no need to amend the supplementary budget that was compiled partly based on those statistics.

(This article was written by Yoshitaka Ito, Shuhei Shibata and Yuki Okado.)