In the olden days (say 5 years ago) EHR data conversion for a small to medium sized medical practice meant moving from paper records to digital records, and that was bad enough: reams of charts had to be scanned in, current data had to be manually input, images , from x-rays to cat scans and everything else had to be converted to pdfs and integrated into a new system.
The thought was that going forward, new information would be input as digital data, and users could get progressively happier as their old paper charts turned scans, aged out of the EHR system.
