Assuming you are running projects where every employee submits their time in a corporate accounting system like SAP or Deltek, should every project always define charge numbers for every WBS item? Why or why not?

Are there exceptions to this rule? Are there instances where you charge labor hours and there is no associated WBS item?

3 Answers 3


Charge numbers and the WBS

Control accounts are issued at the intersection of the WBS and the OBS; they hold the budget for a particular group of people to perform a specific bucket of work and are typically assigned to a control account manager (CAM). The CAM should have authority over how budget is spent and resources consumed within their portion of the project.

CAMs typically break out charge numbers at least one level deeper than their control account. I've seen charge numbers used to collect actuals by smaller elements of the team (i.e. OBS), to break things out in phases to align to a schedule (e.g. charge numbers change after some big review), and/or to collect costs by a lower level of the WBS.

In general, it's perfectly fine for a charge number to span multiple WBS elements--as long as the sub-elements it spans all fall under the same parent. For example, you could have one charge number for 1.2.1 and 1.2.2 and another for 1.2.3, but you don't want to have a charge number for 1.1.2 and 1.2.2 and another for 1.1.3. If you did that, you'll have no way to determine how much 1.1 cost, because it will have 1.2.2 costs embedded with it at the charge number level.

So the hard rule is that charge numbers cannot span WBS elements above the level you're required to report costs at, or to mix charges from WBS elements at the reporting level.

Within that constraint charge numbers can span multiple lower-level WBS elements or you can have multiple charge numbers within a WBS element.

Reasons hours might not be collected against a WBS element

I can only think of a two cases where hours would be charged and there would be no associated WBS item:

  • The WBS is missing something
  • The hours were supporting something you track as overhead, so you should collect them under a special set of charge numbers that map to overhead accounts not program accounts

It depends on which level you wish to follow-up on costs. For instance, if in your WBS you have one deliverable that you have subdivided further into a number of work packages, you could decide to track time and cost against the higher level deliverable, instead of on the individual work packages, while still use the work packages for resource allocation, responsibilities and your schedule.

However, you miss the advantage of following each work package in more detail, compare it with your estimates on these work packages, cannot use it for future estimates etc.

My advice is to always build a WBS to work package level, and track time and cost against them.

We don't track time against individual tasks to create the deliverable of the work package.

For your second question: What would be the scope of the work, if there is no relevant WBS item for it? Then this work would be out of scope, not? The WBS should represent all work to be done. Be wary of what we call "Dustbin" tasks where all kinds of 'unspecified work' is charged against. They tend to spill over very quickly.

  • 1
    I find what I call Release 0 stuff tends to get omitted from the estimates. Thinks like selection and setup of things like servers, development tools, revision control system, bug tracking system, frameworks, processes, etc. In companies which have multiple projects, these should tend to get standardized, and require less time. Good work on release 0 will help the rest of the releases.
    – BillThor
    Mar 8, 2011 at 13:55
  • Agreed. And when standardised, it is easier to estimate. But they should indeed be added as additional work package(s). It is part of the process of delivering the requested product, so this type of deliverables should also be visible on the WBS.
    – Stephan
    Mar 8, 2011 at 15:30

One thing to keep in mind is that if your workers charge their time to X number of charge numbers; the greater the number X is the less likely that they are not making up the numbers. In my experience, most people cannot remember how much time they spent on each discrete task. In our company, asking someone to bill more than 3-4 charge numbers on any project seems to become very generic and less meaningful quite quickly.

This is a delicate balance between having data and possibly slowing the team down or even causing turnover in a data quest. Ask yourself, what are you going to do with the data. Is it really important? Any answer that starts with "it would be nice" or "I might do" I would not do those.

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