Setup an audit team to check hard copy information against the database
information. Pick a certain percentage to check. For instance if data is
entered from hardcopy forms and 250 forms are processed daily then select a
percentage to audit.
In the beginning, you may want to conduct a 100% audit for a week or so to
help weed out those who enter data correctly versus those who make data
entry errors. As time goes by, you can widdle down the percentage of those
who seem to enter data more accurately and beef up audits on those who seem
to have errors.
In other words, there is no easy way or magic answer.