Editing Spiral model (section)

==  History ==
This model was first described by [[Barry Boehm]] in his 1986 paper, "A Spiral Model of Software Development and Enhancement."<ref>{{cite journal |last=Boehm |first=B |doi=10.1145/12944.12948 |title=A Spiral Model of Software Development and Enhancement |journal=ACM SIGSOFT Software Engineering Notes |volume=11 |issue=4 |pages=14–24 |date=August 1986|s2cid=207165409 }}</ref> In 1988 Boehm published a similar paper<ref name=":1">{{cite journal |last=Boehm |first=B |url=http://www-scf.usc.edu/~csci201/lectures/Lecture11/boehm1988.pdf |title=A Spiral Model of Software Development and Enhancement |journal=IEEE Computer |volume=21 |issue=5 |pages=61–72 |date=May 1988 |doi=10.1109/2.59|s2cid=1781829 }} {{webarchive |url=https://web.archive.org/web/20230306211634/http://www-scf.usc.edu/~csci201/lectures/Lecture11/boehm1988.pdf |date=March 6, 2023 }}</ref> to a wider audience. These papers introduce a diagram that has been reproduced in many subsequent publications discussing the spiral model.

These early papers use the term "process model" to refer to the spiral model as well as to incremental, waterfall, prototyping, and other approaches. However, the spiral model's characteristic risk-driven blending of other process models' features is already present: 
{{quotation|[R]isk-driven subsetting of the spiral model steps allows the model to accommodate any appropriate mixture of a specification-oriented, prototype-oriented, simulation-oriented, automatic transformation-oriented, or other approach to software development.<ref name=":1"/>}}
In later publications,<ref name=":0"/> Boehm describes the spiral model as a "process model generator," where choices based on a project's risks generate an appropriate process model for the project. Thus, the incremental, waterfall, prototyping, and other process models are special cases of the spiral model that fit the risk patterns of certain projects.

Boehm also identifies a number of misconceptions arising from oversimplifications in the original spiral model diagram. He says the most dangerous of these misconceptions are:
* that the spiral is simply a sequence of waterfall increments;
* that all project activities follow a single spiral sequence;
* that every activity in the diagram must be performed, and in the order shown.
While these misconceptions may fit the risk patterns of a few projects, they are not true for most projects.

In a National Research Council report<ref>{{cite book |editor-last=Pew |editor-first=R.W. |editor2-last=Mavor |editor2-first=A.S. |date=2007 |url=http://books.nap.edu/catalog.php?record_id=11893 |title=Human-system integration in the system development process: A new look |location=Washington, D.C. |publisher=National Academy Press |doi=10.17226/11893 |isbn=978-0-309-10720-4}}</ref> this model was extended to include risks related to human users.

To better distinguish them from "hazardous spiral look-alikes," Boehm lists six characteristics common to all authentic applications of the spiral model.{{fact|date=August 2014}}