What this actually involves
A document can be borrowed, altered or simply out of date. We check each claim at its source. For an address, a researcher goes there and asks the people who gain nothing either way: neighbours, the landlord, the local council. For a job, we ask the employer's own records office, not the number the applicant gave. For a certificate, we ask the school or the examinations body that issued it. We act only with the person's signed consent, and the report says what was confirmed, by whom, and what could not be.