You’re implementing a new IT system, an app, a DevOps deployment, a DataOps system to merge your data feeds. And it seems to work all right. So, are you done? How much quality assurance work (QA) should you do before calling it finished?
Quality Assurance Methodology
Quality assurance includes testing, but it also means using organized processes to ensure your system works correctly and predictably, in success and in error situations. If you don’t have a definition of your system’s correct behavior, or a list of all the features supposed to be present; if you haven’t kept track of changes; or if you don’t have reproducible tests that verify your system’s actual behavior -- can you know it’s right? Or are you just hoping there aren’t mistakes waiting to be discovered the hard way? Does “quality” just mean wishing for the best?
There’s a reason we say quality assurance. The opposite of QA isn’t bad quality, it’s unknown quality. Maybe your system is great, even flawless. Maybe it’s full of bugs -- serious or inconsequential. Who knows? And what are the consequences of not knowing?
We don’t need to be zealots -- there is no one universal right amount of quality assurance. Many low-impact projects don’t need much. Many teams decide correctly to invest less in QA than they could, simply because their priorities lie elsewhere. Tracking and verifying the expected behavior and actual quality of a complex system is, frankly, work.
Nevertheless, many projects deserve more QA than they are getting, and the decision isn’t being made in a business-like or engineer-like manner. People are improvising and hoping, doing some sketchy testing and, seeing no flames or smoke, moving on. As with security, organizations then learn the hard way: underinvestment leads to very costly problems later.
There is no single right amount of quality assurance
In real life the correct investment in QA depends on the cost of encountering a problem later. If a defect that might exist would take down your company, you should spend whatever’s needed to find and eliminate it (or make sure it wasn’t there). By contrast, if a defect would have no real effect on anyone, why spend time and money on QA at all? QA isn’t about excessive testing and tracking -- it’s about the right amount of testing and tracking. “Process” isn’t a dirty word, but it’s also not a blind ritual or a cult -- it is a tool for successful IT and successful business.
A surprise defect appearing in production is trouble, but how much trouble, and at what likelihood and cost? Nearly all projects live between the two extremes of “don’t promise, don’t look” and “test everything every time you move a finger.” If we don’t have an explicit discussion about quality, defects, the unknown, and all their consequences, we can’t decide what to spend on quality assurance.
Quality assurance plan: a useful scale
Here at FP Complete we’ve described a simple quality assurance scale to ease such discussions. Projects can range from QA level 0 (can’t make assertions about the quality) to QA level 5 (would bet human lives on the system working as intended).
Have a look at these, and ask whether your QA level today is in line with your real business goals, and with the price of failure in your business.
Level 0: No quality criteria
There’s no specific attempt to know whether the code or installation is suitable for use. Maybe it works correctly, maybe it doesn’t. Such work should be labeled as a “draft” or “prototype” or “unfinished preview” or similar warning.
Suitable for: projects where complete failure is acceptable, such as learning experiments.
Level 1: Minimal QA
No formal quality vetting is included in the project requirements. The work has been inspected by its creator (the engineer or technician who implemented the solution), the basic functionality has been tried and appears to work correctly, and the creator believes it is suitable for use. However, no record clearly shows that the required functionality has been implemented and works as intended.
Most often, a list does not even exist stating all the required functionality; or if such a list does exist, it may not be complete and up-to-date. Lacking such a list, it is literally not possible to show whether a quality bar has been met or not.
Suitable for: prototypes, or a low-budget situation tolerant of failures that can be corrected after the fact.
Level 2: Traditional QA
We call this “traditional” because it characterizes what most companies do on most projects, not because we think it represents the usual correct decision.
The key functionality points (such as features or commands) have been listed in a document, and for the most important ones, a documented test (manual or automated) for a typical success case is implemented, and is run. A report or log of these tests and runs is kept and can be provided to the customer, to show how well tested the work is. Source code is maintained under version control with a clear history. Bugs and unfinished work are tracked in an issue-tracking system with a clear history.
Suitable for: production use in a risk-tolerant situation, in which failures are undesirable but can be tolerated and repaired. (Especially for low-volume production use, where the limited number of runs means any given bug may not be triggered, or may affect only a small number of users.) Also for high-grade experimental use.
Level 3: Commercial QA
In addition to everything in level 2, the key functionality points and most of the secondary functionality points are documented and tested, each in at least one success case, many in at least one failure case, and where appropriate, in corner and/or fuzz (randomized) cases. Where appropriate, load/stress/capacity testing is applied. Where relevant, basic automated intrusion testing is applied. My previous post about multifaceted testing explains more about these different kinds of tests you may want to include.
At this level, using more than one pair of human eyes is also appropriate. Documentation describes the basic design of any complex solution, and is reviewed by an engineer who did not write it. The implementation is reviewed (such as code review, or examining a cloud configuration) and approved by an engineer who did not create it.
Suitable for: production use in a routine business situation, with reduced tolerance for risk, where failures may involve costly consequences that could easily exceed the costs of proper QA work. For example, a production system that will be used by the majority of your customers, such that a missed defect could seriously impact your revenues or your reputation.
Level 4: Sensitive quality
In addition to everything in level 3, all exposed functionality points are documented and tested in success and (where applicable) various failure and corner cases, or any omissions explicitly listed. A report is provided showing when each test was last run and against what build, and whether it passed, with any not-run or not-passed tests having a written explanation. Version control logs and issue-tracking logs show the linkage between checkins, tickets, and documented specifications or requirements. Thorough design documentation is included, suitable for review by a third-party auditor. All code is reviewed by at least one engineer, and suggested clean-ups and refactorings documented and (where appropriate) implemented.
Suitable for: production use in a risk-intolerant situation, in which a single failure could have severe costs greatly outweighing the cost of proper QA, such as a major business process automation, a real-time pricing system, a high-volume website, or a risk-management system. Also for: formal audit or regulatory inspection, where an external regulator must be shown that the system has met firm criteria for controls and reproducibility, such as an FDA Class II medical device.
Ask yourself “Will we have to interrupt major business if this system doesn’t work as intended?” If so, you want at least this level. Ask also “Will we get in trouble if we cannot prove we were very careful?” If so, you want at least this level. On your way there, you can prioritize which QA features fit your budget and your business priorities.
Level 5: Critical quality
In addition to everything in level 4, every exception (such as an untested case or a case that doesn’t pass all its tests) is reviewed by an expert committee and either sent back for correction, or waived with a formal sign-off regarding its known acceptable safety impact. Tests of failure modes, and system survivability after severe load and failure-driven stress events, are routine. Attacks, randomized inputs, and defective data are routinely included in the automated test suite. Where available, formal methods, source code analysis, and execution profiling are also used. Even the requirements themselves are subjected to scrutiny regarding their validity and thoroughness. The toolchain is required to provide complete traceability of any work present in the final product. An inspection is done to ensure that no feature or case, explicit or implicit, has gone unlisted and escaped the QA process.
Suitable for: projects in which a failure could result in serious bodily harm, death, or another intolerable loss. For example, real-time manned vehicle control, or an FDA Class III medical device. Or an automated investment system that trades hundreds of millions of dollars without human supervision.
Deciding on a Quality Assurance Plan
So quality assurance can range from quite trivial, to a powerful structure that can heavily affect your engineering process, culture, schedule, and budget. That’s an amazingly large range. How to choose?
Consider these key factors:
- What is the total cost to our company of the routine defects we tend to see? Is it more than improving our QA would cost?
- What would be the total cost to our company of a really bad defect that was released unknowingly? Is this cost, weighted by its probability, worse than improving our QA?
- Are we doing so much QA that it’s hampering our ability to operate the business? That is, are we letting the quest for perfection block the release of product that’s good enough for our users and stakeholders?
- Are we meeting all regulatory and contractual requirements? Will that be agreed if a regulator or a lawsuit causes our engineering to be inspected, or our records to be reviewed?
- Do we have enough education in testing and project management that we even could improve our QA? If not, do we have access to experts who can teach us, and/or the ability to hire staff with the needed background?
- Do our top management and our culture support quality as much as they support getting new features out the door, or is this an evangelism situation requiring culture change?
In the real world you will always hear voices saying “hurry up and get done, at less cost” and other voices saying “only the best will do for our users and our data.” These are all important values, and there is a never-ending balancing act to get enough of all of them. Be thoughtful and wise, and don’t assume that “out of sight currently” means “doesn’t count.”
How to get the discussion started?
Here at FP Complete, we have the good fortune to serve lots of very smart companies’ engineering and IT teams, from FinTech to medical devices to secure online services. We see the results of QA first-hand, and we see how necessary it is. A focused, intentional, best-practices approach to QA is how companies get better results from their technology projects.
I recommend raising the issue of quality assurance at your weekly/monthly team meetings and management meetings. Rather than assuming one right approach, raise questions and start the discussion. How much QA is right for this team, and this project? Here are some ideas for questions.
- I know we try to ship a quality product. How confident are we that unknown defects aren’t lurking in there? What would it take to do better?
- There have been scary stories lately about companies with security holes and other costly bugs. How can we make sure we’re not one of those stories next year?
- We’ve built a culture that focuses on innovation and meeting user needs. But have we also focused enough on predictable quality? Are we sometimes improvising where we should be engineering?
- There seem to be a lot of people out there who know much more about quality than we do. Can we afford to leave things this way? Is quality a competitive vulnerability where another firm could start upsetting and stealing our users, or make us look bad?
- We’ve invested heavily in quality assurance. Is it time to institute a decision-making path, to ensure that QA isn’t too heavy on one project, or too light on another?
- Could we turn great quality into a competitive advantage?
Quality assurance is an evergreen topic -- always relevant, and likely to gain in importance for a long time. Let’s all give it the attention it deserves.
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