A plot of age against time, consisting of lines inclined at 45° representing the lifetimes of individuals. Each line starts with birth (or immigration into the population) and ends with death (or emigration from the population).
Lexis diagram. Diagonal lines show lifetimes of individuals; vertical lines show points in time. There were three people aged 60 at the beginning of 2001. Of these, one died later that year aged 61. In 2002 a 61-year-old immigrant entered the population.
Subjects: Probability and Statistics.