THEORY AND METHODS FOR ANALYZING ERRORS IN MAN‐MACHINE SYSTEMS

Systeins Research is a broad research program covering a great variety of fundamental and applied studies on naval information systems. Two important objectives of this program are: (a) the evaluation of naval radar equipment in terms of the accuracy, kind, and amount of information an operator can extract from it, and (b) the development of suitable techniqiies for carrying out these evaluations. The results of our cfforts to accornplish the second objective form the substance of this paper. The theory and methods to be discussed here are the result of cooperative speculation on the part of several individuals who have wrestled with these prob1ems.t We can claim no genuine originality for these methods, however, sirice the equations and formulae upon which they depend have been available in statistical and mathematical literature for a long time. And yet, the practical researcher cannot find this material discussed in any single source except in the most abstract terms. The chief contribution of this paper, perhaps, is that (a) it develops systematically several important concepts and formulae for analyzing errors in complex man-machine systems, and (b) it demonstrates by practical examples the applications of these equations to the analysis of errors in such systems. Our primary interest in these methods has been directed toward the solution of radar problems, but it has become increasingly apparent that the concepts involved apply equally well to many other kinds of intricate systems, such as are found in modern industry. Although we have had no occasiori to observe these techniques at first hand in industrial situations, examples of their use can be found. Severa1 industrial examples have been used in this paper to show the generality of tha methods and possibly to suggeçt still further applications.