184 BUREAU OF AMERICAN ETHNOLOGY [Bull. 197 



but whose structure reflects a system of theoretical inferences which 

 may not be observed among the avaihible data.-^ 



A word should be added in regard to the possible misinterpretations 

 which may attend the development of such constructs by demographers 

 who attempt to cope with data of limited quality or quantity. The 

 conclusions reached by demographers who analyze data for a given 

 population tend to have an immediate impact upon the policy decisions 

 of administrators who are concerned with the population in question. 

 It is therefore especially important that the demographic analyst 

 should maintain a careful distinction between the data as given and 

 the data as interpreted or adjusted. In practice, however, this distinc- 

 tion is difficult to preserve, especially where the data as given may 

 reflect biases or omissions which the demographer can adjust or correct 

 far more readily and accurately than can the ultimate user of these 

 data. Perhaps the most efficacious policy, under these circumstances, 

 is for the demographer to carry out whatever adjustments appear to 

 be warranted in the data as given, while providing an explicit account 

 of sucli adjustments. On the other hand, the administrator or other 

 user of these data must be cautioned that the reliability of adjusted 

 data and the validity of inferences derived therefrom, are no greater 

 than the reliability and validity of the original data. 



We are led, on the basis of these considerations, to the second ap- 

 proach, which is to undertake a direct program aimed at developing 

 a single set of administratively useful population records, utilizing to 

 the fullest degree the recent technological advances in the recording, 

 processing, and recall of the data obtained. The most essential feature 

 of such an approach would be the preparation of a schedule on which 

 could be recorded the demographic, economic, and health data which 

 are essential to the several administrative programs that are carried 

 out among the Navaho. 



One of the greatest difficulties with the present system of data col- 

 lection among the Navaho lies Avitli the variety of uncoordinated oper- 

 ations whereby each administrative service conducts its own surveys, 

 assembles its own data, and attempts to determine its policies on the 

 basis of the necessarily partial information so obtained. The result is 

 a vast accumulation of records, none of which represents a fully ade- 

 quate description of the population as a whole. Furthermore, periodic 

 attempts to match these records with one another, in order to verify 

 information, omit possible duplications, and reveal other inconsisten- 



28 The development of the "ideal type" concept is traced in Johnston, MS. 



An excellent summary of the dangers inherent in the use of mathematical constructs is 

 provided in Kaplan, 1960. 



Additional articles on the use of models in social science have been written by Rapoport 

 (1959) and Brodbeck (1959). Brief summaries of the use of such models in demographic 

 analyses Is given in International Union . . . , 1959; Yntema (1952) ; and Lopez (1961). 



