When Fixing It Doesn't Fix It: II

To repair complex systems, many resort to "random twiddling and part replacement" (RTAPR) when they're under time and resource constraints. Sadly, RTAPR doesn't work very well. For example, consider a system that has six commercial off-the-shelf components. Let's suppose that it isn't working right. We decide to replace Module 2, which produces no change — the system continues to misbehave. Some might conclude that this proves that Module 2 is OK, but that conclusion might be mistaken. Suppose that the problem lies in the firmware of Module 2, which controls how it operates on the data it receives from Module 1. Since both of our Module 2 boxes contained the same firmware, the system behavior didn't change when we made the swap. A conclusion that Module 2 was not involved in the fault would therefore be incorrect.

A more careful approach can work better than RTAPR. Here are some guidelines that form the basis of what is usually called the scientific method.

Perform no random experiments

Random experiments, especially those involving system configuration changes, are unlikely to produce new knowledge. The more complicated the system, the less productive are random experiments.

Keep excellent records

Record the Random experiments, especially if
they involve system configuration
changes, are unlikely to
produce new knowledgedetails of all experiments and results. Typically, you won't refer to these notes until you're completely stumped, but that happens with alarming frequency for complex systems. So write the notes so as to make them clear in that kind of desperate situation.

Try to replicate unwanted behavior

(a) If the unwanted behavior is reliably repeatable, observe the results of making a minimal change to the system. Any change in behavior can be revealing. (b) If the unwanted behavior isn't repeatable, try to find a system configuration that makes it repeatable, and then go to (a). In all such experiments, controlling the system's containing environment is essential.

Base all attempts on hypotheses

Because the input configuration for a complicated system is also complicated, proving that complicated systems work for all required inputs is difficult. Hypotheses about why the system isn't working are equally difficult to prove. Hypotheses can more readily be disproven than proven.

Therefore, have a testable hypothesis in mind whenever you change the system configuration. Testable hypotheses are of this form (for example): "The fault might be A. If experiment B produces behavior C, then the fault cannot be A." Repeating this process gradually eliminates possibilities until only the truth remains.

Fail forward

Devise hypotheses and experiments that cause your investigation to "fail forward." That is, favor experiments that produce useful knowledge whatever the outcome of the experiment. If you make a change and the system starts working, that should help explain what was wrong. And if that same change causes some other result, that, too, should be enlightening information.

Adhering to these guidelines can be difficult, especially under pressure. If deviation is required, make note of it, and note how deviations affect your conclusions.   First issue in this series   Top    Next Issue

Are your projects always (or almost always) late and over budget? Are your project teams plagued by turnover, burnout, and high defect rates? Turn your culture around. Read 52 Tips for Leaders of Project-Oriented Organizations, filled with tips and techniques for organizational leaders. Order Now!

Your comments are welcome

About Point Lookout

Thank you for reading this article. I hope you enjoyed it and found it useful, and that you'll consider recommending it to a friend.

This article in its entirety was written by a human being. No machine intelligence was involved in any way.

Point Lookout is a free weekly email newsletter. Browse the archive of past issues. Subscribe for free.

Support Point Lookout by joining the Friends of Point Lookout, as an individual or as an organization.

Do you face a complex interpersonal situation? Send it in, anonymously if you like, and I'll give you my two cents.

Related articles

More articles on Problem Solving and Creativity:

Bois Sec!

When your current approach isn't working, you can scrap whatever you're doing and start again — if you have enough time and money. There's a less radical solution, and if it works, it's usually both cheaper and faster.

Virtual Teams Need Generous Travel Budgets

Although virtual team members who happen to be co-located do meet from time to time, meetings of people who reside at different sites are often severely restricted by tight or nonexistent travel budgets. Such restrictions, intended to save money, can contribute to expensive delays and errors.

The Expectation-Disruption Connection

In technology-dependent organizations, we usually invest in infrastructure as a means of providing new capability. But mitigating the risk of disruption is a more powerful justification for infrastructure investment, if we understand the Expectation-Disruption Connection.

Disproof of Concept

Proof-of-concept studies of system designs usually try to devise solution options and discover the system's operating constraints. But limitations can become clear too late. A different approach — disproof of concept — can be a useful alternative.

Goodhart's Law and Reification

Goodhart's Law, applied to organizations, is an observation about managing by metrics. When we make known the goals for our metrics, we risk having the metrics lose their ability to measure. The risk is elevated when we try to "measure" abstractions.

See also Problem Solving and Creativity and Critical Thinking at Work for more related articles.

Forthcoming issues of Point Lookout

Coming July 3: Additive bias…or Not: II

Additive bias is a cognitive bias that many believe contributes to bloat of commercial products. When we change products to make them more capable, additive bias might not play a role, because economic considerations sometimes favor additive approaches. Available here and by RSS on July 3.

And on July 10: On Delegating Accountability: I

As the saying goes, "You can't delegate your own accountability." Despite wide knowledge of this aphorism, people try it from time to time, especially when overcome by the temptation of a high-risk decision. What can you delegate, and how can you do it? Available here and by RSS on July 10.

Coaching services

I offer email and telephone coaching at both corporate and individual rates. Contact Rick for details at rbrendPtoGuFOkTSMQOzxner@ChacEgGqaylUnkmwIkkwoCanyon.com or (650) 787-6475, or toll-free in the continental US at (866) 378-5470.

Get the ebook!

Past issues of Point Lookout are available in six ebooks:

• Get 2001-2 in Geese Don't Land on Twigs (PDF, )
• Get 2003-4 in Why Dogs Wag (PDF, )
• Get 2005-6 in Loopy Things We Do (PDF, )
• Get 2007-8 in Things We Believe That Maybe Aren't So True (PDF, )
• Get 2009-10 in The Questions Not Asked (PDF, )
• Get all of the first twelve years (2001-2012) in The Collected Issues of Point Lookout (PDF, )

Are you a writer, editor or publisher on deadline? Are you looking for an article that will get people talking and get compliments flying your way? You can have 500-1000 words in your inbox in one hour. License any article from this Web site. More info