Addition of Sample Enterprises to the Tankan
February 22, 2021
Research and Statistics Department
Bank of JapanThe Bank of Japan has decided to add 2 enterprises to the Tankan (Short-Term Economic
Survey of Enterprises in Japan) sample from the March 2021 survey.
As a result, the total number of sample enterprises for the March 2021 survey will be
9,852 (including 204 financial institutions, 162 business consultants & pure holding
companies and 597 sample enterprises in the Survey on Overseas Business Activities). 1
To prevent a decrease in the number of sample enterprises—due to bankruptcies, mergers,
and other factors—from causing a decline in the statistical accuracy of the Tankan, theBank examines the statistical accuracy once a year and adds new sample enterprises ifnecessary. Moreover, in the case that a non-core enterprise which was not selected as asample enterprise at the time of the spin-off, but which now has an impact above a certain
level on the estimate of the population total in the Tankan, the Bank may incorporate it
into the sample enterprise to capture the whole picture of the pre-existing sample
enterprise even though some time has passed since the spin-off. 2
Details of the examination for the statistical accuracy of Tankan are as follows. 3
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 389 strata by industry, enterprisesize and sales for the estimation of the population total.4 The Bank examined whether
there is a statistically significant difference in these strata between the sample andpopulation distributions. 5 The result showed that there was no stratum in which the1597 sample enterprises in the Survey on Overseas Business Activities includes the 589 sample
enterprises of the Tankan and the Survey of Business Consultants & Pure Holding Companies.
2 For details of the statistical accuracy of the Tankan, please refer to "Explanation of the Tankan(Short-Term Economic Survey of Enterprises in Japan)," May 2020.
3 This examination was carried out using the sample enterprises after the most recent survey inDecember 2020.
4 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.
5 The "test of the goodness of fit" using chi-square distribution is used in the regular examination.

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sample distribution was deemed to deviate from the population distribution.6
2. Standard Error Ratios
The Bank examined the standard error ratio of sales 7 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.8
Standard Error Ratios of Sales

Manufacturing

ActualLarge

Medium-Sized

SmallEnterprises

Enterprises

Enterprises

0.7%

1.8%

1.8%

Criterion
Nonmanufacturing

Actual

3.0% or less
1.2%

Criterion

2.2%

1.7%

5.0% or lessInquiries
Business Survey Group, Economic Statistics Division, Research and Statistics
Department
E-mail: post.rsd5@boj.or.jp
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.
6 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 23 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 yen
or more and then classified into 3 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 totalsales.) The result showed that there was no stratum in which the sample distribution was deemed todeviate from the population distribution.
7 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.
8 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 6.3% (in the Survey of Financial Institutions), 1.5% (formanufacturing on Overseas Business Activities) and 3.8% (for nonmanufacturing on Overseas
Business Activities). They were within the criterion, 10%.

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