Alternative Forms
Different versions exist for many of these measurements. Where revised versions have come to be widely accepted and used, we include these in the Description section of the method. The Alternative Forms section covers other variants and translations Again we have been selective: for some methods there has been a proliferation of less frequently used, minor variants that should not be encouraged. These have been ignored.
Reference Standards
Where available, these provide normative infor mation with which the results of the user's study may be compared Commentary Descriptions of each measurement are as objec- tive as possible, the Commentary section offers some remarks on the strengths and weaknesses of the method and on how it compares with oth ers with a similar focus. In conjunction with the summary tables at the beginning of each chapter, this is intended to help the reader choose between alternative measurements and to suggest where further developmental work may be carried out.