APPLICATION OF RESEARCH KNOWLEDGE TO PANEL LAYOUT PROBLEMS 



169 



Third, further work must be done on the use 

 of size coding and the use of shape, color, 

 and size coding on controls other than levers. 

 In general it may be said that coding controls 

 makes good psychological sense as far as the 

 reduction of confusion errors are concerned, 

 but it must be tried out in the practical situa- 

 tion where the overall efficiency of the op- 

 erator can be measured with and without 

 the benefit of coding. 



Standardization and Coding of Displays 



Practically no work has been done on the 

 problem of confusing one display for another. 

 For one thing, the problem appears to be less 

 serious than in the case of controls, at least 

 as far as aircraft are concerned. In a study 

 on errors made in the use of displays, Fitts 

 found that only 13% of the errors recalled by 

 pilots could be classified as substitution or 

 confusion errors (14). He suggests, as in the 

 case of controls, that these errors may be 

 reduced by standardizing the positions of 

 displays in all planes, and by designing dis- 

 plays that are likely to be confused as 

 distinctively as possible. Similar recom- 

 mendations may be found elsewhere in the 

 hterature (25). In general, it is suggested 

 that displays that might be confused should 

 be separated spatially, be given distinctively 

 different shapes, be coded by color, and pos- 

 sibly by size. Here again much specific re- 

 search is necessary before it is possible to 

 know how to design displays that will not be 

 confused with each other by the operator. 

 And again, it is necessary to be sure that 

 making displays distinctive does not inter- 

 fere with the efficient use of the individual 

 displays themselves. 



The Application of Research 



Knowledge to Panel 



Layout Problems 



When it comes to the application of our 

 knowledge of human capacities to the prac- 

 tical panel design situation, it is obvious 

 that the data and recommendations consid- 

 ered above represent only a fraction of what 



we need to know. Much more experimental 

 work is needed before we have anything like 

 complete information relevant to problems 

 of panel layout. The six principles de- 

 scribed above serve well to deUneate some of 

 the major problems in panel design. As new 

 knowledge of human capacity is apphed to 

 panel layout problems, they may be ex- 

 tended to ten or more; or they may be syn- 

 thesized further into only three or four gen- 

 erahzations. In any case, these principles 

 must be implemented further with relevant 

 quantitative data before they are of practical 

 value to the design engineer. Research in 

 this area must be extended until every rec- 

 ommendation that is made for panel design 

 can be supported by quantitative specifica- 

 tions of panel layouts. As recent experi- 

 ments have shown, for example, it is no 

 longer of any great value to point out that 

 controls must be within easy reach of the 

 operator. We must be able to indicate the 

 limiting dimensions of panel layouts that 

 will be satisfactory for known populations of 

 operators under various conditions of op- 

 eration. When data of this sort are avail- 

 able for all the principles of panel design, 

 we will be in a much better position to 

 evaluate equipment in current use and in the 

 design stage. Then we can make practical, 

 concrete recommendations for redesign that 

 will satisfy the hmiting requirements of hu- 

 man capacity. 



Practical Compromises in Panel Design 



Since panel layout problems have to be 

 faced with the data at hand, however, it is 

 well, at this point, to clarify some of the 

 problems involved in the application of re- 

 search knowledge to practical panel design. 

 A considerable amount of compromise will 

 be involved in any satisfactory panel layout. 

 To begin with, it should be recognized that 

 at least three major compromises will have 

 to be made. In the first place, it should be 

 apparent from the above discussion that it is 

 not possible to arrange controls and displays 

 in accordance with each principle of panel 



