Biologists in every field are today finding themselves continually hampered by the incompleteness of their information concerning the biotic factors of environment. Furthermore, much of the information now available is not of the maximum possible value because the basic data are often not comparable. Tn order that biotic information may be of maximum value, it must be expressed in accurate comparable terms. This necessitates a standardization of methods used in collecting and recording information. Our biological problems are not always local in character and their solution, even in the same locality, often depends upon the efforts of more than one investigator. Each worker may approach the problem from a different angle and use entirely different methods from his local predecessors and his co-workers in other places, so that it may be difficult if not impossible to compare satisfactorily his results with those of others. A detailed study of abnormal conditions existing at any one time or place might lead to the development of curative methods applicable in the future, not only to that locality but also to other similar places. The desirability of applying the results obtained in one time or place to problems in another is obvious. But such application would be impossible unless the work in the first instance could be correctly interpreted by others. To do this satisfactorily requires that similar observations should be made and the results interpreted in a standard way. This of course does not imply the application of these standard methods to the exclusion of all others. Many kinds of observations do not lend themselves to standardization at present. But in estimating damage, animal abundance, and other environmental conditions the consistent use of standardized methods wherever they can be successfully applied would make the work of one investigator more easily understood and used by others, and would make possible the comparison and co-ordination of data from many localities. Another advantage of the general use of certain standardized methods lies in the fact that biotic phenomena of one kind may have an important influence on phenomena of quite a different nature. Sometimes these effects are local, but in other instances they may have an influence even in distant localities. If our information concerning various kinds of biotic phenomena were expressed in standardized terms, greater correlation of data would be