As in the first edition, Europeans in Europe have been chosen as the baseline population against which comparisons will be made with other world populations. The reason for this is the large number of investigations that have been carried out on Europeans in the past using standardized techniques. Europe also has the advantage of a population that is close to being genetically homogeneous. European populations do vary considerably in adult size, however, and this variation also is seen in the size of the children.

Selection of European studies

One of the main difficulties in making a comparative growth survey is that the various samples of children are rarely comparable in the strictest sense. Different investigators have often used different methods, not so much of measuring technique, but of sample size and selection, age grouping, number of measurers, and area sampled. For this reason, we have never pooled data from different studies in a country to calculate a national average. In some countries genuinely national samples have, been measured, and when these are available, we have used them. When they are not, we have used urban samples in preference to rural ones, for all the evidence at present shows that when there is a difference, children in cities grow better than those in rural areas. At times when we have found two good studies from the same country, we have recorded both in the tables.

Many countries collected and analyzed new data in the 1970s and 1980s and only these are presented here in Table 2. Data from 1955–70 will be found in the first edition of this book.