ovm_transaction vs. ovm_sequence_item
DAC 2009 Presentation Schedule: JL Gray

Do You Know Your Project's 'Truck Factor'?

Yesterday I presented another full-day workshop on verification planning - this time in Denver. During these workshops I discuss two major topics. First, we discuss a framework to help you understand your design. We break up a design into "efficient" subsections, and then search for "operations" that make up each of these subsections. Second, once you have an understanding of your design, we discuss the concept of a Failure Mode and Effects Analysis (FMEA). An FMEA is a cross-functional meeting used to brainstorm possible faults and failures. We use that information to come up with a verification plan.

During the first part of the workshop, I often share stories of projects I've worked on where there was either an unmanageable amount of documentation, or conversely, too little documentation. While sharing these stories I like to introduce the concept of the "Project Truck Factor".  What is the Project Truck Factor, you ask? Simply, the PTF is the number of people on your project who could be hit by a truck before your project suffers serious consequences (see also here).

A project with a low PTF is characterized by a combination of the following:

  • Lack of documentation
  • Extreme specialization of individual contributors
  • Lack of knowledge sharing between engineers
  • Engineers assigned individually to complete key project goals

Note that any one of these by itself may not cause a dangerously low PTF. But taken together, a project can get into serious trouble if a key contributor:

  • goes on vacation
  • becomes ill
  • is out of the office for a family emergency
  • quits
  • is actually hit by a truck

How do you deal with a project with a low PTF? In theory, it's easy. Make sure you have good documentation and that more than one person is familiar with key program concepts. You may also want to assign people to work on tasks in pairs.  In reality, improving a project PTF can be difficult. If a key engineer can complete a task in an hour that would take a week, it's hard for a manager to justify giving others a chance to do the work.  Managers also tend to speak highly of documentation, but not of the time it takes to create said documentation.  The key is for managers to realize that this is a serious project risk factor that needs to be addressed early enough to prevent the PTF from becoming low to begin with.  


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