It views one's life as a socially sequenced timeline and recognizes the importance of factors such as generational succession and age in shaping behavior and career.
[2] The origins of this approach can be traced back to pioneering studies of the 1920s such as William I. Thomas and Florian Znaniecki's The Polish Peasant in Europe and America and Karl Mannheim's essay on the "Problem of Generations".
[5] The primary factor promoting standardization of the life course was improvement in mortality rates brought about by the management of contagious and infectious diseases such as smallpox.
[3] The method encompasses observations including history, sociology, demography, developmental psychology, biology, public health and economics.
[10] It has also become increasingly important in other areas such as in the role of childhood experiences affecting the behaviour of students later in life[11] or physical activity in old age.