2.8 Wilhelm Lexis and graphical diagram

In the 19^th century the German mathematician and economist Wilhelm Lexis (1837-1914) developed the two-dimensional approach that helps temporal examination of population phenomena.

Wilhelm Lexis examined the co-ordinate system, years on the x-axis and age on the y-axis. The temporal units of different axes are equal; that is, one year corresponds to one calendar year. The Lexis diagram makes it easier to follow the accumulation of age and the passing of years.

At the same time as Wilhelm Lexis was developing his diagrams, the German demographers Karl Becker and Gustav Zeuner were developing similar description methods for population phenomena. These diagrams are also known by their surnames.