Regular Examination of the Statistical Accuracy of the Tankan
February 27, 2023
Research and Statistics Department
Bank of JapanThe Bank of Japan examines the statistical accuracy of the Tankan (Short-Term Economic
Survey of Enterprises in Japan) regularly (once a year in principle), to prevent thelowering of statistical accuracy due to a decrease in the number of sample enterprises
resulting from bankruptcies, mergers, and other factors. When accuracy is not sufficient,
the Bank adds new sample enterprises. The recent examination showed that the statisticalaccuracy after the December 2022 survey satisfied the criteria. The total number of thesample enterprises for the March 2023 survey will be 9,636 (including 257 financial
institutions, 170 business consultants & pure holding companies and 583 sample
enterprises in the Survey on Overseas Business Activities).1
Note: For details of the statistical accuracy of the Tankan, please refer to "Explanationof the Tankan (Short-Term Economic Survey of Enterprises in Japan)," February2023.
Details of the examination are as follows.
1. Sample Distribution
In the Tankan, the population is determined as private enterprises with capital of 20
million yen or more (excluding “financial institutions” and “business consultants & pureholding companies”). The population is classified into 384 strata by industry, enterprisesize and sales for the estimation of the population total.2 The Bank examined whether
there is a statistically significant difference in these strata between the sample andpopulation distributions. 3 The result showed that there was no stratum in which the583 sample enterprises in the Survey on Overseas Business Activities includes the 573 sample
enterprises of the Tankan and the Survey of Business Consultants & Pure Holding Companies.
2 In the Tankan, the Bank places the restriction on selecting sample enterprises in order to limit
disturbance to the estimates due to an idiosyncratic factor of a sample enterprise: the sampling ratioof each stratum is maintained at 0.5 percent or more. The Bank verified that there was no stratumwith sampling ratio of less than 0.5%, along with the examination of the statistical accuracy on theabove.
3 The "test of the goodness of fit" using chi-square distribution is used in the regular examination.
This method tests the null hypothesis, H0: "There is no significant difference between the sample andpopulation distributions." When the hypothesis is statistically rejected, the sample distributions aredeemed to deviate from the population distributions.
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sample distribution was deemed to deviate from the population distribution.4
2. Standard Error Ratios
The Bank examined the standard error ratio of sales 5 in manufacturing andnonmanufacturing for each enterprise size in the Tankan. The results showed that thestandard error ratios remained within the criteria — 3% or less for manufacturing and 5%
or less for nonmanufacturing — as listed in the table below.6
Standard Error Ratios of Sales

Manufacturing

ActualLarge

Medium-Sized

SmallEnterprises

Enterprises

Enterprises

1.1%

1.7%

1.9%

Criterion
Nonmanufacturing

Actual

3.0% or less
1.3%

Criterion

2.0%

1.6%

5.0% or lessInquiries
Business Survey Group, Economic Statistics Division, Research and Statistics
Department
E-mail: post.rsd5@boj.or.jp

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The Bank also examined whether there is a statistically significant difference in the strata between
the sample and population distributions in the Survey of Financial Institutions, the Survey of Business
Consultants & Pure Holding Companies and the Survey on Overseas Business Activities. (In theSurvey of Financial Institutions, the population is determined as financial institutions with 10employees or more and then classified into 22 strata by sector and the number of employees. In theSurvey of Business Consultants & Pure Holding Companies, the population is determined as private
enterprises that are “business consultants & pure holding companies” with capital of 20 million yenor more and then classified into 4 strata by sales. In the Survey on Overseas Business Activities, thepopulation is determined as private parent enterprises excluding “financial institutions”, with capitalof 1 billion yen or more, at the top of a consolidated business group with sales to overseas externalcustomers or overseas subsidiaries/branches, and then classified into 73 strata by sector and total
sales.) The result showed that there was no stratum in which the sample distribution was deemed todeviate from the population distribution.
5 Standard error ratio shows how accurate an estimate of the survey population mean is. It is calculatedby dividing the standard deviation of the sample mean by the survey population mean.
6 The Bank also examined the standard error ratios of fixed and software investment (excluding landpurchasing expenses) for overall financial institutions in the Survey of Financial Institutions, andtotal sales for both manufacturing and nonmanufacturing on Overseas Business Activities. The result
showed that the standard error ratios were 5.0% (in the Survey of Financial Institutions), 1.7% (formanufacturing on Overseas Business Activities) and 3.7% (for nonmanufacturing on Overseas
Business Activities). They were within the criterion, 10%.

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