Talk:Spiral model

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Hmm, is Spiral model synonymous with Agile Methods, or is it an example of an agile method or is it something else entirely? I haven't heard of spiral model in real world programming before. Seems like it's an expressly chosen opposite to waterfall model or so. 17:20, 12 Feb 2004 (UTC)

Found it elsewhere in the wikipedia. It influenced the development of Agile Methods. 17:35, 12 Feb 2004 (UTC)

English diagram[edit]

I love Germany and Germans, and yes they make great engineers, but since this is the English language Wikipedia perhaps the diagrams should be in English? Tolstoy143 - "Quos vult perdere dementat" (talk) 00:24, 7 April 2008 (UTC)Reply[reply]

Someone vandalized my comment above, which I'll leave as it is and simply make this additional comment (Wikipedia still has no remedy for these types of hack-and-slash comment vandalism). In any case, my previous comment used to say positive things above Germany and only pointed out that the English wikipedia probably needs English diagrams. Tolstoy143 - "Quos vult perdere dementat" (talk) 13:29, 28 January 2009 (UTC)Reply[reply]
Thanks for noticing. I removed that vandalism. -- Marcel Douwe Dekker (talk) 16:32, 28 January 2009 (UTC)Reply[reply]

spiral model example[edit]

Can you have sample documents of spiral model software engineering? for example, the information that should be included and how to construct a spiral model methodology?

hope to here from you soon... thank you!


1 - basic info which should be included in "spiral documentation" would include application name, purpose, functionality, architecture/component info, interface/networking considerations (either with other applications and/or customers) etc...but I question the value of having sample documents, as they can and do vary a great deal.

2 - you do not 'constuct a spiral model methodology' as it is a methodology in itself, albeit a high-level one.

Not just in software[edit]

Future Combat Systems also uses spiral development. I'm formatting with that in mind. Are we sure it was first applied in the software field?

Well, I imagine that you could see NASA's efforts with the Mercury, Gemini, and Apollo programs as a form of spiral development, although it may not have been given that name. Then NASA fell victim to Big Design Up Front with the space shuttle... --Allan McInnes (talk) 17:39, 26 April 2006 (UTC)Reply[reply]

But INTENDED for software[edit]

The spiral model recognizes the benefit of rapid prototyping, wherein the "bottom-up" people gain insight at a rapid rate that the "top-down" people can learn from. Thus a cycle of continuously improving the design requirements becomes possible during the design itself. It is thought to allow a more optimal final design, based on the notion that there are no suitable experts that can write the requirements at the start of a design exercise that will lead the team to an optimal design.

This is a critical aspect of invention, where something totally new is being considered. In this situation, specific expertise is limited or unavailable (and therefore disvalued) during the early stages of design (but ye must have faith that expertise is developing). This is known to work well on small scale projects, where all team members are in close contact and work in a flexible manner. Rapid prototyping is after all unencumbered by massive documentation requirements and free of production constraints.

A real concern with the application of the spiral model outside of the software world is one of design efficiency of large scale projects: this may challenge the very business case that makes the project possible. Great leadership is required if the spiral model is to be used with thousands of people writing design and test requirements simultaneously with thousands of others optimizing the design and planning design upgrades before new requirements are captured. Chaos can result, leading to a gap between a few great prototypes and high quality production parts.

Consider two examples. NASA's JPL was tasked to land on Mars and drive a vehicle around. At the program initiation, there were no experts as this was never accomplished before. A few years and many dollars were invested, and a few highly optimized vehicles landed and roved the surface of Mars. Each vehicle had differing malfunctions, but the fact remains that the mission overall was accomplished and stands as a great scientific achievement. The spiral model might have been very successfully employed here, where one might expect that optimization of the design was one of the most important aspects to the success of the program.

In another example, let's say GM is tasked with developing a new mini-van. The task is to build the best design achievable but also reach mass production (which requires long term planning for substantial tooling, quality and safety testing, and a business plan for costs risks and returns). The success of the program will be judged on the execution of the business case, where costs must be controlled carefully: these costs are heavily dependant upon avoiding schedule delays, avoiding quality problems, avoiding tooling errors, avoiding safety compliance shortcomings, and meeting the needs and desires of sufficient customers who can choose not to buy the mini-van at all. The spiral model is a risk here. While a good design is needed, the optimal design is less important than a brilliant execution of top down design to achieve a high quality production product on time and within budget (especially if designing something substantially more complicated than a mini-van).

If there was a linear scale, with invention or experimentation on one end (like the Mars project) and with mass production programs which expect world class quality of its products (like a new GM mini-van) at the other end, then we might be able to appreciate the applicability of the spiral model outside of the software world: its suitability depends upon the intended project goals. An experiment in state of the art (research?) projects may benefit from a spiral process that favors a more optimal final design rather than a cost-effective design process. A production project on the other hand cannot trade off the cost-effective process for a more optimized design: when the design is close, it is close enough. It may be more important to keep the thousands of people working in unison on clear requirements that freeze in time for tooling and specification writing and prototype testing to complete itself exactly when needed. To delay the program at any time may very well be as to cancel the program.

To consider the spiral model, you must intimately know just how serious you are about going to production, be you a scientist or a businessman. Mbbradford 06:39, 8 November 2006 (UTC)Reply[reply]

Peer review requested for waterfall model.[edit]

Hi, I've just requested peer review for waterfall model. I'd really appreciate if some people could review the changes I've made. Thanks.  :) GeorgeBills 15:03, 17 November 2005 (UTC)Reply[reply]

"This persisted until the year 2000?"[edit]

In the second paragraph, last sentence, what persisted until the year 2000? A 6 to 2 year iteration cycle, and all iterations stopped then? Did a shorter or longer iteration cycle become accepted as a new standard? If someone can clarify, it would be an improvement (I would clarify, except I have no idea what the sentence means.) Chris van Hasselt 20:01, 12 January 2006 (UTC)Reply[reply]

I don't know what was supposed to be meant by this phrase, and I came in here to post just such a question. Since over four months have passed since the above question was asked, I removed the offending sentance. If anyone wants to restore it, please indicate what "this" refers to. Keithmahoney 20:49, 27 May 2006 (UTC)Reply[reply]

clean up[edit]

I just did a lot of clean up to the physical appearance of this article, and it looked as though someone copied and pasted all the information from another pre-formatted location (aka plagiarism). Anyone know where the info might have come from?--Jude 04:05, 31 January 2007 (UTC)Reply[reply]

Thanks for finding the source! I removed everything that was added to the article by whomever.--Jude 10:28, 2 February 2007 (UTC)Reply[reply]

1988 or 1986 ?[edit]

In the article, Barry Boehm's article "A Spiral Model of Software Development and Enhancement" is dated with 1988, but this ACM reference shows a publication date of nearly 2 years earlier: August 1986. I have also found a IEEE reference corresponding to the date mentioned in the article: May 1988. If anyone could agree, I would like to correct the date on the article page. Kak (talk) 15:37, 2 June 2008 (UTC)Reply[reply]

-- Kak, your're correct. His first paper was 1986. His IEEE paper was published in 1988. By the way, the image of the spiral is incorrect. It starts out in the wrong quadrant. Also, to be a true spiral, risk analysis is required, so it should be shown as a necessary step. —Preceding unsigned comment added by (talk) 23:14, 4 September 2008 (UTC)Reply[reply]

FCS is a bad example[edit]

I worked on FCS, and continue to work on its follow-on, Brigade Combat Team modernization (BCTM). FCS was not cancelled because of its development methodology. It was cancelled because the Secretary of Defense decided that major parts of it were either unnecessary or not cost effective. Remember that FCS included many types of vehicles and weapons systems, not just software. Large parts of the software have been retained in BCTM, and our basic methodology has not changed much, mostly in scheduling. -- (talk) 21:09, 30 March 2010 (UTC)Reply[reply]

Error in Spiral diagram[edit]

The spiral model diagram as it appears has a numbering error. Clockwise it lists:

1. Determine objectives

2. Identify and resolve risks

2. Development and test

4. Plan the next iteration

(that should be a 3 instead of the second 2).

Strangely, when I check the media itself at,_1988).png the displayed media has the same mistake, but when I check the "file history" at,_1988).png#filehistory the "latest version" entry appears corrected (?!). I don't understand the wikimedia commons edit-process well enough to ascertain what is wrong. Can someone else please? --Donkeydonkeydonkeydonkey (talk) 16:37, 2 August 2010 (UTC)Reply[reply]

Five months later there is still the same problem with the incorrectly numbered image. Can anyone fix it (or am I stupidly not realising that there is a reason for it to be like that?) — Donkeydonkeydonkeydonkey (talk) 22:04, 7 January 2011 (UTC)Reply[reply]

Copyright problem removed[edit]

Prior content in this article duplicated one or more previously published sources. The material was copied from: Infringing material has been rewritten or removed and must not be restored, unless it is duly released under a compatible license. (For more information, please see "using copyrighted works from others" if you are not the copyright holder of this material, or "donating copyrighted materials" if you are.) For legal reasons, we cannot accept copyrighted text or images borrowed from other web sites or published material; such additions will be deleted. Contributors may use copyrighted publications as a source of information, but not as a source of sentences or phrases. Accordingly, the material may be rewritten, but only if it does not infringe on the copyright of the original or plagiarize from that source. Please see our guideline on non-free text for how to properly implement limited quotations of copyrighted text. Wikipedia takes copyright violations very seriously, and persistent violators will be blocked from editing. While we appreciate contributions, we must require all contributors to understand and comply with these policies. Thank you. NortyNort (Holla) 01:02, 4 June 2011 (UTC)Reply[reply]

Sorry for asking but that source particular from doesn't strike me as an original source. There is no author give, and two different dates: 2001 and 2006-2011. The website itself also doesn't strike me as very notable..? Now I made some further inquiries and came up with some remarkable facts.
  1. The lines of that text seem to be quoted on the web in numerous documents
  2. The original source of the idea is the article Barry Boehm (1998) "A Spiral Model of Software Development and Enhancement" in: IEEE Computer 21, 5, 61-72, 1988, but the specific text doesn't seem to be from that source.
  3. I found the original source to be the US Gov publications nr NUREG/CR-6888 ORNL/TM-2005/75: Emerging Technologies in Instrumentation and Controls: An Update. Oak Ridge National Laboratory. U.S. Nuclear Regulatory Commission Office of Nuclear Regulatory Research Washington, DC 20555-0001. Written in 2005, published jan 2006, pp 34-35
  4. Now this text seems to be a Public Domain publication.
  5. It seems to me User:Kumud hi added that exact text in this Wikipedia article on 19 February 2007, see here.
  6. ... and also the whole website seems to be started somewhere in 2006, months after the US gov publication.
I came up with the following conclusion:
  1. It is highly unlikely that is the original source
  2. It is most likely that US Gov publications is the right source, and that this is a PD document
If this is true, then there was no copyright violation here. -- Mdd (talk) 19:44, 4 June 2011 (UTC)Reply[reply]
The site states it was last updated in July 2001 and that was all I had to go off of and when one editor pastes the text in question during a single edit, it looks more suspicious. I also can't see web archives of that page at all, I believe it blocks web crawlers. The site could have merged with another site over the years as well, I am not sure. With all this, I thought it best to remove the text.
I downloaded that US Gov source and yes, there is a word-for-word copy in there. The one thing that worries me is the disclaimer on p. 2: "Where the papers In these proceedings have been authored by contractors of the U. S. Govemrnment, neither the U.S. Government nor any agency thereof, nor any U.S. employee makes any warranty, expressed or Implied, or assumes any legal liability or responsibility for any third partys use or the results of such use ... or represents that its use by such third party would not Infringe privately owned rights. The views expressed In these proceedings are not necessarily those of the U. S. Regulatory Commission." There is copyrighted (marked) material in that document and I am not sure the rest can be considered PD. I am not saying you are wrong, I am confused as well. At first I thought the site was a mirror. I will make a note on this article's entry at Wikipedia:Copyright_problems/2011_May_26 and an administrator who will probably be more familiar than I will have a look.--NortyNort (Holla) 23:49, 4 June 2011 (UTC)Reply[reply]
I marked the article as infringing copyright, but only as the messenger relaying the message received from a TechTarget representative. Whether TechTarget improperly claimed copyright over work in the public domain, I do not know. There were about 25 articles they claimed infringed upon their copyright and I did not do more than a cursory examination to verify that the last modification date was earlier than the presence of the material in the article. The first article in the list for the ticket was checked by another volunteer against an Internet Archive copy to verify that it was indeed in existence before the article, so we believed that the text was indeed copied from the TechTarget site. If there are PD sources available, then rewriting the content based on those sounds like the safest option. – Adrignola talk 01:37, 5 June 2011 (UTC)Reply[reply]
Ok, thank you both. I agree with NortyNort all the way; looked at some of those other copyright claims; and learned some more along the way... but I have found no new facts about this particular case (of this article). I took the alternative solution, Adrignola suggested, and found an other PD source. I guess my initial analysis still stands, but I don't need that (removed) text restored. -- Mdd (talk) 21:41, 5 June 2011 (UTC)Reply[reply]
Your welcome, this is a particularly unusual case.--NortyNort (Holla) 22:43, 5 June 2011 (UTC)Reply[reply]
Mmmm...!? I found an entry on Experts-Exchange, see here, by jvuz from 10/05/04 05:33 AM which sort of confirms is the original author. This is definitely older then the US Gov publications, and seems to prove that the (new) site was merged with another site. The link address given in that entry is,,sid8_gci755347,00.html . If we can trust the time-stamp on the Experts-Exchange, then I was wrong here, wand we can closed this case. -- Mdd (talk) 23:47, 5 June 2011 (UTC)Reply[reply]

In spiral diagram the spiral should start in the first sector (?)[edit]

The sprial should start in the first sector, shouldn't it? See page 25 of -- Tkalmi (talk) 12:58, 28 December 2011 (UTC)Reply[reply]

Proper protocol for major rewrite?[edit]

I am a newly registered Wikipedia user, so I want to check the protocol before I proceed with any changes to this article. "Be bold" is one thing, but I'm thinking major rewrite, not tweaking.

I assert that this article has many inaccuracies and incorrectly characterizes Boehm's spiral model. I stipulate that the article content is consistent with many, many secondary sources, but those secondary sources are inaccurate. I am prepared to support this with authoritative primary sources: Boehm's original article and more recent writings where he discusses common misinterpretations of the model.

Given that I would like to do a major rewrite of the article, what would be the proper way to proceed?

Please note that I'm not trolling, and not trying to start a flame war. Just asking politely how to proceed. Thanks.

SteveMattingly (talk) 01:39, 25 October 2012 (UTC)Reply[reply]

Major rewrite posted[edit]

I just posted the significant rewrite that I asked about nearly a year ago. --SteveMattingly (talk) 00:51, 27 August 2013 (UTC)Reply[reply]

Details of alleged errors in diagram?[edit]

Can anyone provide support for the most recent update's assertion that the diagram contains errors? I find that the diagram is consistent with the one in Boehm's authoritative sources, so I would not agree that there are "errors". A better description of the situation, as covered in the article, is that Boehm's original diagram has been widely misunderstood. SteveMattingly (talk) 16:50, 31 July 2014 (UTC)Reply[reply]

It does not agree with the diagrams shown in the articles of Boehm (1988) and Boehm (2000). It is clear that the diagram in the latter article is better. — Preceding unsigned comment added by Adelpine (talkcontribs) 14:12, 1 August 2014 (UTC)Reply[reply]
This is a confusing, but important, issue. It is true that the article's diagram does not exactly match every detail of the diagrams in any of Boehm's publications. If I could exactly reproduce Boehm's original diagram, I would, but I don't know how I can legally do that.
"It is clear that the diagram in the [2000] article is better." Better than what? By what criteria? In the same publication as the diagram you call "better", Boehm says that the diagram "contains some oversimplifications that have caused a number of misconceptions to propagate".
My goal through all of my edits has been to show that, according to Boehm himself, his ideas have been widely misunderstood. This is largely because a diagram that shows one possible application of the model has been misinterpreted as an essential definition of all applications of the model. SteveMattingly (talk) 20:40, 30 January 2015 (UTC)Reply[reply]

Correct citation of image source requested[edit]

Just grab the original spiral model drawing from the original article and cite it (it can be downloaded without any problems from google scholar)? I would prefer that over an own interpretation of the model with an incorrect citation. The current citation communicates that the image was drawn by Boehm but infact it was drawn by the author of the Wikipedia article. Here is the excerpt from the title page of the original article by Boehm from which a correct citation could be extracted:

CarnegieMellon Software Engineering Institute Pittsburgh, PA 15213-3890 Spiral Development: Experience, Principles, and Refinements Spiral Development Workshop February 9, 2000 CMU/SEI-2000-SR-008 Barry Boehm, edited by Wilfred J. Hansen July 2000 COTS-Based Systems — Preceding unsigned comment added by (talk) 10:28, 14 February 2018 (UTC)Reply[reply]