Home > Articles > Software Development & Management

Unsustainable Software Development and its Causes

Unsustainable development is an all-too common situation today in the software industry. Unsustainable development is a development pace that is typified by stress, frustration, and a sense of not being in control. It is most evidenced by a continually increasing cost of change and defect rate and a corresponding decreasing ability to respond to changing conditions. This chapter explains how unsustainable development begins, and how to head it off before it spirals out of control.
This chapter is from the book

Unsustainable development, as depicted in Figure 2-1, is an all-too common situation today in the software industry. Most software teams place too much of a short-term emphasis on feature development and fixing defects and do not pay enough attention to the health of the underlying software. The result is software with a high cost of change, that is increasingly unmaintainable, and where every change has the risk of destabilizing the product.

Figure 2.1

Figure 2-1 Unsustainable development is characterized by a constantly increasing cost of change to the software. The usual evidence of a high cost of change is a constantly increasing number of defects. Each change adds complexity and uncovers or causes defects that require more changes, and this complexity leads to a declining ability to respond to customer requests and changes to the ecosystem.

In unsustainable development, teams tend to spend an ever-increasing amount of time fixing defects and stabilizing the software. Features still get developed, but less time is available for feature development due to the amount of time required to stabilize the software, which increases with each new release. This results in teams tending to become change-adverse while they are stabilizing the product because each change increases the risk that something will break. Teams tend to desire freezing of requirements as early as possible so they can get some work completed. This reduces their ability to respond to customer requests and changes to underlying hardware or software because they are spending too much time on stabilization, which is wasted effort, and not enough on new work.

The symptoms of a short-term outlook are only evident once a threshold has been crossed. This is the point where the development team starts to spend so much time trying to keep up with the defect backlog that they are noticeably unable to spend enough time to develop new features. It may take only a few months or many years to reach this point. Many development teams may not even be aware how bad things are: Release cycles might become death marches, customers, management, and sales force complaints might get louder, and developers themselves will start blaming the problems on management ("if only they had listened to me...") and other developers ("they produce too much buggy code..."). It may take a while, but morale will eventually suffer then plummet; in extreme cases, people will lose their jobs through being fired, layoffs, or outsourcing, and customers will lose patience with the product and company.

Luckily, the extreme is seldom reached. Unluckily, most project teams live in a gray area that is not sustainable development but is uncomfortably close to unsustainability. These projects have not reached the threshold where the problem is obvious; developers feel like they are barely keeping up or are making slow progress but with too much stress. This is the software development death spiral, where the only variable between unsustainable projects is the rapidity of the descent toward obvious unsustainability.

Technical Debt and the Flywheel

The underlying cause of the inability to develop new features due to a defect burden is what is best called technical debt. Technical debt is caused by an accumulation of poor decisions over time—decisions that often seem right at the time but are usually made in the interests of a short-term quick fix to the software. Very rarely is it possible to identify a single decision that stands out as one where the problems might have started.

Jim Collins describes a relevant flywheel metaphor [Collins 2001]. Collins uses the flywheel metaphor to describe how decisions affect momentum in an organization. Think of a massive flywheel that is so large all you can do at first is give it tiny nudges that move it an inch at a time. Your organization’s sustainable development emphasis is like continually providing tiny nudges. Each new nudge adds momentum to the flywheel so that it continues to pick up speed. However, every decision to develop a new feature or fix a bug by introducing an ugly hack or ignoring the underlying architecture acts as a brake on the flywheel. The software development death spiral results because these brakes, or nudges in the wrong direction, will eventually stop or even get the flywheel spinning backwards. How fast the flywheel is spinning and its direction is something your organization should be aware of.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020