The Electoral Commission informs me that it has not made any estimate of the number of electoral registration officers (EROs) who did not undertake local data matching trials following the dry run of confirmation in 2013. 139 EROs reported results to the Commission but there are likely to have been other EROs who carried out some activities but did not report it to the Commission.
The Commission further informs me that it did ask EROs, on a separate survey, whether local data matching would be important during the live run of confirmation and 91% said that it would.
The Commission therefore expects more EROs to conduct local data matching for the live run of confirmation than reported on results following the dry run.
The Commission, working with Cabinet Office, will be collecting data from all EROs after the live run of the confirmation process which will demonstrate levels of usage of local data in practice. This data will be published on the Commission's website.