Implementing Structured Requirements to Improve Requirements Quality

Abstract

The Boeing Company has implemented a standard approach to the engineering of high-quality requirements using the concept of "structured, natural language", a specific grammar for how to write requirements. This approach helps our requirements engineers write more unambiguous and verifiable requirements as required by ISO/IEC/IEEE 29148:2011 and related commercial and military standards.Boeing has identified four types of specification requirements, plus a verification requirement type. Each type of requirement has a standard grammar, a set of mandatory and optional elements that ensure verifiability related to the type. This approach is implied by recent guidance from the International Council on Systems Engineering (INCOSE), and by recommendations of other industry practitioners.In combination with these standards for writing requirements we have also integrated a scoring method for evaluating how well any requirement satisfies the standard criteria. This approach provides immediate feedback to the requirement writer regarding the absence of critical information or deficiencies in the information provided, e.g., unobservable functions, or ambiguous performance criteria or conditions. In contrast with other industry methods we score elements of the requirement individually on a graded (rather than binary) scale. We are thus able to not only score for the presence or absence of a required element, but are able to identify degrees of compliance with the Boeing standard. This enables us to quantify the risk of less-than-perfect requirements.The updated INCOSE SE Measurement Primer (INCOSE 2010) describes SE measurement as a closed-loop feedback control system (Figure 1). For requirements development, the specific process outputs or work products are the requirements themselves in their various specifications. The closed-loop feedback control model then requires direct measures of the quality and completeness of the requirements as the first step of process control. The completeness of sets of requirements has already been addressed by (Carson et al. 2004).

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“…3 Requirement patterns as shown in [13]. Patterns are originally from [14]. The parts between square brackets are optional Requirement management starts with a proper definition of the stakeholders, needs, and requirements.…”

Bilgi Sistemi Yazılım Geliştirme Yaşam Döngüsü Safhalarından Gereksinim Belirleme ve Sistem Tasarımında Kalite Odaklılık: Üç Proje İncelemesi

“…Ayrıca, bir gereksinimin standart kriterleri ne kadar iyi karşıladığını değerlendirmek için bir puanlama yöntemi de belirlenmiştir. Sonuçta bu yaklaşım, gereksinim yazarı olan iş analistine, kritik bilgilerin veya eksikliklerin bulunması konusunda geri bildirim sağlamıştır [13].…”

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“…[26]. An interesting work dealing with textual requirement patterns is proposed in [27], where the author suggests a few kinds of pattern according to the type of requirement. However, only writing high quality requirement statements is not sufficient to assure the success of the project.…”