The new method takes into account stocks and repayments of loans that have been derecognised and removed from balance sheets, the ECB said.
The new method also includes data on repayments and stocks of securitised loans that are serviced by monetary financial institutions (MFIs) after being derecognised. This was necessary because of new regulations regarding the balance sheets of MFIs, the ECB said.
The statistics also took data on other derecognised loans into account where they were available, the bank said."
Previously, the ECB's statistics, adjusted for sales and securitisation, only took into account transactions resulting from loan transfers, on or off balance sheet, in the period when the transfer took place.
Comparable back data has been put together by the ECB along with national central banks, to offer a consistent statistical series from the beginning of 2010.
The new method of calculation has resulted in lower adjusted flows and growth rates, the ECB said. For the 12 months to July 2015, the growth rates of loans to the euro area private sector, households and non-financial corporations have been revised downwards, on average by 54 basis points, 77 basis points and 41 basis points, respectively, it said.