Nonlinear Work: When Superposition Fails

More often than we'd like, our projects are late or over budget. Or we find that the problem we've tackled is much more difficult than we thought. We aren't stupid (though some might argue otherwise), and we aren't trying to gild lilies our build empires (though some might argue with that, too). Still, these things happen with such regularity that there must be an explanation.

Part of the answer might be that much of the work we do is of a nature that our minds have difficulty comprehending. One property that gives us trouble is nonlinearity.

For example, consider the issue raised by Fred Brooks. [Brooks 1982] If three people can complete a task in six months, many would suppose that nine people can complete it in two months. We now understand that this belief is unfounded, and that our expectations are rarely met.

To understand why, let's begin by defining linear work. Work is linear when the outcomes are directly traceable from, and scale with, inputs. When work is linear, we can successfully plan the outcomes before we begin, because we can predict the course of the effort. To make linear tasks go faster, we can divide them into parts that we execute in parallel, without risking complication.

For example, two identical, independent assembly lines can produce output at double the rate of one single line, assuming that their supply and delivery chains are also independent. A manufacturing process implemented as independent assembly lines is a linear process.

But In a system that doesn't
obey superposition, the whole
can be different from
the sum of its partsnonlinear work doesn't follow this pattern. Although most of the work we do in project-oriented organizations behaves linearly in response to small adjustments, the nonlinearities dominate when we scale those adjustments to a size where we expect to derive large benefits. One attribute of nonlinear work that explains this phenomenon is its failure to obey superposition.

In a system that doesn't obey superposition, the whole can be different from the sum of its parts. In such cases, as we apply more and more resources, the yield per unit of resource can decline. In the case of Brooks's mythical man-month, this can happen because of increased need for management and communication, and increased difficulty in scheduling.

But superposition can fail for a wide variety of reasons. For example, when we decompose a problem into parts, and try to work on the parts separately, one task team might require — solely for scheduling purposes — that another task team take an approach that is less effective than it would have taken if it were free to act independently. We can easily generate numerous examples like this that show failures of superposition that confound our expectations.

In three weeks, we'll continue this exploration of the reasons why nonlinear work is so difficult to manage.   Next 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!

Footnotes

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 Project Management:

Managing Non-Content Risks: II

When we manage risk, we usually focus on those risks most closely associated with the tasks at hand — content risks. But there are other risks, to which we pay less attention. Many of these are outside our awareness. Here's Part II of an exploration of these non-content risks, emphasizing those that relate to organizational politics.

Design Errors and Groupthink

Design errors cause losses, lost opportunities, accidents, and injuries. Not all design errors are one-offs, because their causes can be fundamental. Here's a first installment of an exploration of some fundamental causes of design errors.

Design Errors and Group Biases

Design errors can cause unwanted outcomes, but they can also lead to welcome surprises. The causes of many design errors are fundamental attributes of the way groups function. Here is Part II of our exploration.

Depth First or Breadth First?

When investigating candidate solutions to a problem, we tend to focus first on what we believe is the "best bet." But a more systematic approach can sometimes yield dramatic advantages by reducing the cost of the investigation and the time it requires.

Lessons Not Learned: I

The planning fallacy is a cognitive bias that causes us to underestimate the cost and effort involved in projects large and small. Mitigating its effects requires understanding how we go wrong when we plan projects by referencing our own past experience.

See also Project Management for more related articles.

Forthcoming issues of Point Lookout

Coming June 25: Meandering Monologues in Meetings: Engagement

In a meeting, a meandering monologue has taken over when someone speaks at length with no sign of coming to a clear point, and little of evident value. This behavior reduces engagement on the part of other attendees, thereby limiting the meeting's value to the organization. Available here and by RSS on June 25.

And on July 2: The True Costs of Contractors

Among the more commonly cited reasons for hiring contractors instead of direct employees is cost savings. But are these savings real? Direct compensation, including perks and benefits, might favor the contractor arrangement, but indirect costs tell another story. Available here and by RSS on July 2.

Coaching services

I offer email and telephone coaching at both corporate and individual rates. Contact Rick for details at rbrenaXXxGCwVgbgLZDuRner@ChacDjdMAATPdDNJnrSwoCanyon.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