Ambiguity in Limited Entry Decision Tables The use of decision tables as a tool in systems analysis and for program specification is now becoming accepted. Rules on redundancy, contradiction, and completeness for limited entry tables were published in 1963. These are usually used for checking, preceded if necessary by a conversion from extended to limited entry form. Processors which automatically translate tables to more conventional program usually base their diagnostic facilities on these rules. In this paper it is suggested that these rules are unsatisfactory and that the important aspect of checking is to eliminate ambiguity from tables. Ambiguity is defined and discussed, and a procedure for producing checked-out decision tables is proposed. The theoretical basis of the algorithm used is established. The importance of well-designed diagnostic facilities in decision table processors is emphasized. CACM October, 1968 King, P. J. H. decision tables, DETAB-65, systems analysis 3.50 4.19 4.49 CA681003 JB February 21, 1978 4:17 PM 1684 4 1684 1684 4 1684 2053 4 1684 2220 4 1684 2273 4 1684 2453 4 1684 2726 4 1684 2856 4 1684 3113 4 1684 1354 5 1684 1564 5 1684 1684 5 1684 1684 5 1684 1684 5 1684 2053 5 1684 2517 5 1684 2518 5 1684 2616 5 1684 3034 5 1684 931 6 1684 1172 6 1684 1237 6 1684 1327 6 1684 1354 6 1684 1548 6 1684 1548 6 1684 1684 6 1684 1684 6 1684 1684 6 1684 1684 6 1684 1684 6 1684 2053 6 1684 2053 6 1684 2221 6 1684 2517 6 1684 2517 6 1684