Try this:

select whoverified, whochecked AS 'userid', count(*) whoverified, count (*) whochecked

from rxproductivity

join users us1 on rxproductivity.whoverified = us1.userid

join users us2 on rxproductivity.whochecked = us2.userid

group by whoverified, whochecked

having count(whoverified) > 1

order by count(whoverified) desc