Japan has begun a revamp of its gross domestic product numbers because of rising concern about their accuracy, following a Bank of Japan report that suggests a huge understatement of growth in 2014.
An official Cabinet Office study group met for the first time on Wednesday and separate groups in other ministries are examining the figures, amid fears that data problems could affect economic policymaking.
The overhaul highlights growing issues with GDP data around the world because of declining response rates to official surveys. Unreliable numbers leave central banks and finance ministries flying blind as they try to set economic policy.