New Delhi, May 8 -- Once a globally renowned institution, India's Central Statistics Office (CSO) today faces the gravest credibility crisis in its history. An investigation by Mint has found that a key database of companies picked up in 2015 as an input source to calculate its new series of gross domestic product (GDP) is riddled with gaps, large enough to distort final output figures. It was bad enough that serious infirmities had been pointed out in other aspects of the revised calculation exercise. The GDP deflator now in use to reduce the nominal size of the economy to its real figure may have misrepresented overall inflation, for example; secrecy over this deflator had cast some doubt over our new GDP growth numbers, drawn now from inflation-sensitive measures of value-addition. The latest revelations seem to confirm other suspicions of the new methodology. As Mint reported on Wednesday, a significant share of companies in the aforementioned database could not be traced by field staff of the National Sample Survey Office (NSSO) involved in a year-long hunt that ended in mid-2017. Other firms had been misclassified; since groups of registered firms in specific sectors are used as proxies for commercial activity in the informal sector, this must have had distortive effects of its own. The field staff also noted that several firms in the database had dodgy accounts....