The steps taken to estimate the representative curves of height and weight for differenc countries or regions of the world were as follows:-
All the relevant literature, published after 1960, which could be traced was examined. The annotated bibliography includes the references together with brief notes on the size and nature of the samples studied.
When potentially useful data were provided these were tabulated in rank order within geographical regions. An abridged form of this tabulation, which was done with the aid of a micro-computer, is given in table I. This tabulation confirmed that there were very wide variations between samples within geographical regions and, sometimes, even within countries.
Table I gives the information required to produce a growth curve for each sample studied but the very large number of curves which might be drawn would not result in a meaningful representation of the heights and weights of whole populations. It was therefore necessary to simplify the data so that each geographical region would be represented by a reasonably small number of curves. Therefore:-
Those studies which gave the best representation of their regions or countries were selected from the total.
The data from these studies were compared with the centiles for the United States of America (WHO, 1979). Henceforth the terms “US centile” or “centile” without further qualification will refer to these centiles.
For each sex and age group, in each sample the mean stature or weight was recorded as the centile nearest to which it lay. Thus the minor variations in the original table of cms or Kg (Table I) were eliminated as the precise values were replaced by more approximate figures (e.g. 50, 40, 30 etc) representing centiles. From this table it was possible to discern whether a population mean lay consistently on one centile or whether its centile status changed with increasing age.
The above table was further simplified by dividing the whole age span into four periods:- 0–4.9 years; 5–9.9 years; 10–14.9 years and 15+ years. The centile which best represented each country within each age period was identified and the countries were tabulated according to these centiles. The result of this procedure is table II which forms the basis for the next stage of this discussion.
