1) they currently resided in this district

2) they were not older than age 80 years

3) the diagnosis of NMSC as a primary, first tumor was confirmed histologically during 1996-1999

Population controls were ascertained from a random address sample of the mandatory registry of the district and frequency-matched to cases on gender and age (5-year classes).  bmj.com/epidem/epid.html

Coggon D, Rose G, Barker DJP

Epidemiology of the Unitiated.

BMJ Publishing Group 1997

Contents

5. Planning and conducting a survey