Some aspects of growth with norms from birth to 18 years.

Several cross-sectional studies of children's body measurements have been made from which average growth may be inferred (Hammond, 1953a; Provis and Ellis, 1955; Clements and Pickett, 1955 and 1956 for school ages. Low, 1952; Acheson and Hewitt, 1954; Hammond, 1955; Thomson, 1956 for pre-school ages). But it is impossible to assess the significance of departures from average growth unless normal growth variability is known, and this can be ascertained only from actual differences shown by individuals between successive measuring occasions. Usually growth is studied over one year, but its consistency over longer periods can be assessed by comparing successive years' growth with each other and with that of the longer periods. The data used in this paper, collected from a number of different studies, are based on growth measurements taken over intervals of 1 to 3 years from birth to late adolescence. They consist of measurements of growth taken by the author in the following investigations: