Japan Monthly Index
To measure policy-related economic uncertainty for Japan, we construct an index based on frequency counts of articles in Japan's two largest-circulation daily newspapers, Asahi and Yomiuri.
Newspaper coverage of policy-related economic uncertainty
Our index method follows the same basic approach as we apply to American newspapers in constructing a monthly index of policy-related economic uncertainty for the United States. As with our U.S. index, we first count the number of newspaper articles containing the terms uncertain or uncertainty ('futoumei' or 'fukakujitsu'), economic or economy, and one or more policy terms. Our policy terms are the Japanese-language equivalents of 'policy', 'tax', 'spending' by the government, 'regulation', 'Bank of Japan' or 'BOJ', 'budget', and 'deficit'. To capture 'spending' by the government, we use a set of four terms: 'saishutsu' (budget outflows), 'kokyo jigyohi' (public undertaking), 'kokyo toushi' (public investment), and 'kokuhi' (national spending).
We divide this frequency count by the total number of articles in the same newspaper and month, and we then rescale these newspaper-level ratios to unit standard deviation from June 1988 through December 2013. (Before computing the ratio of the EPU count to the total count for Yomiuri, we adjust for a large permanent upward level shift in the total number of Yomiuri articles that occurred from October 1998 to October 1999.) We then average over the resulting newspaper-level indexes month-by-month to obtain an index for Japan. Finally, we normalize this index of economic policy uncertainty for Japan to a mean value of 100 from June 1988 to December 2013.
With each monthly update, data from the preceding two months may be revised slightly, as well. This is driven by the fact that some online newspapers do not immediately update their online archives with all articles, leading to slightly changing totals for the previous 1-2 months.
We would like to thank Jörn Boehnke, Yuto Ezure, and Ippei Shibata and for their help in developing our Japan EPU Index. Given the 'beta' nature of our Japan index, we welcome any comments or suggestions for how to improve it.