A close ogy to a study design is the rough sketch made by an artist before he commits his vision to canvas(画布)．The broad outlines are drawn, the proper perspective achieved, and the total impact of the picture-to-be can be partially appreciated in advance．So it is with the design of research: it specifies in advance the kinds of statements that can be made on the basis of its findings and fixes the perspectives against which these findings are to be evaluated.
One major purpose of this study was to demonstrate whether or not the newer social re search techniques could help in broadening and deepening knowledge concerning juvenile delinquency(少年犯罪)．Construction of the design was guided by this goal of exploring new methods ill the ysis of juvenile delinquency．However, research technique developed in one content area can not be mechanically transferred to another．A new application of them requires substantial changes and it is these innovative modifications which this study offers as its contribution.
Juvenile delinquency has been the subject of many previous studies using a variety of re search techniques．This study makes an additional contribution by using a design specially planned to permit a comparison of several approaches.
The drawing-up of the study design profited greatly from an extensive survey of previous researches on crime, undertaken during the earliest stage of the project．It was found that most studies could be classified as belonging to one or more of three broadly conceived types: social background study, family background study and personal motivation study.
Each type has its characteristic design and mode of interpretation and each has produced information of considerable importance．Yet no attempt was made in any of the studies to integrate one or more of these three design types．It became apparent that one of the major contributions a pilot study could make to both method and substantive findings would be to bring all three study types together in one design for the purpose of correlating(使相互关联) their find rugs and evaluating their relative importance in producing data of use to the practitioner.
In the first paragraph, the author draws an ogy between ______.