Abstract This paper proposes a scoring method of document quality for prevention of incomplete or ambiguous System (or Software) Requirements Specification (SRS). The proposed method quantifies degree of completeness and unambiguity of a SRS document as a score on a 100-point scale. Smaller score indicates incomplete and/or ambiguous SRS so that makes the development stakeholders aware of the project’s risky condition. It provides an opportunity to discuss more clear requirements and prevent inaccurate estimation. In addition, this paper explains a case study for verifying usefulness of the proposed method and reliability of the resulted scores. In the case study, the project managers’ comments are explained as well as the scoring results of the 10 system developments. 1. ˘ˇˆ˙˝˛˚˜ !"#$ %&' ()˜*+,-./01/˜23 045 ˙!6˛789:˜; ?:@A ˝B0C(DE FG%HIJ˜KLJMDE% NO ˘˝˛˚˜NO DEPQRSTUVW%HIJ˜XYZ9[\]^%C ˘_ 0`\%ab cdS ef%ghJ˜ijk]Flem % n [1]˘ NOo-0pqNOr˙˜ˇˆ!st˙˝˛˚!stuvwxryz˜ab{|{0}~•!€C(†‚C(r y [2]˘˝˛˚r˜ˇˆrƒ„ !"# !…†%a‡˙JMˆˆ˜cJ‰DE %|tJMˆˆC(%S+SJˆR˜a‹ŒR“dM./%C{Ž„M+!‚C(˜|dSC{Žˆ-M./0‘:’ [‘’%“” M+!€C(r• ˙˘ – Z—:B!S˜r™s ˙›˜_ %œ{sžŸdS€; M+`\ci,ŒJˆ¢ [6]˘ £¤˜ !NOo-˙pqNO%¥¦ M+˜ !§¨%©a« ¬