The index is re-based and the weights are revised every 5 years. Within one month after the end of the reference month. The Research and Statistics Department is the department responsible for compiling the data for the Indices of Industrial Production. Most of the monthly basic data concerning the indices have been obtained from the result of Current Survey of Production. This survey is designated statistics stipulated in the Statistics Law of March 26, 1947.
METI publishes the data on the production index as a service to the public.
No government officials outside the METI have access to the data prior to their release to the public. The Director of Current Statistics Division of METI provides comments, technical and interpretative, on the data. The data are preliminary when first released and are revised twice. When the revised report for March is published, each index for every month of the previous year is revised to compile the final series. The public is informed of major changes in methodology in advance.