CHAPTER 6
Service Breakdown Structure

Chapter 4, “Scope of Maintenance,” introduced the Maintenance Machine, which represents all the services needed to run maintenance. This chapter provides a list of all of the services as well as a breakdown of the activities, which further clarifies the scope of maintenance. This list can be used as a checklist for a new manager who’s just taken over a maintenance team or as a refresher for an experienced manager.

The format of the list of services and activities is called the Service Breakdown Structure (SBS). The SBS is a modification of the classic project management Work Breakdown Structure (WBS). The WBS can’t be used for maintenance because its lowest level represents work packages that can be assigned to individuals. That level is inapplicable to the IT maintenance team.

In the SBS, the lowest level represents a distinct type of work to be performed, but the quantity, duration, and effort level will not be known ahead of time. Unlike development projects, most of these maintenance activities will run in parallel, with few predecessor (start to finish) relationships. You will be able to make assumptions from the breakdown in the lowest level about how many items you will get of each type of work so that you can predict effort and staffing needs, which will be helpful in your estimating the cost of maintenance. The next chapter (Chapter 7, “Cost Estimate”) will present additional methods for estimating maintenance cost.

Figure 6-1 presents a sample SBS. Review this sample to determine which services and activities apply to your circumstances, delete the ones that don’t apply, and add any that are missing. Most of the tasks in the SBS are performed continuously. A few need to be performed only once, which is indicated in parentheses.

Identify what group will perform each activity. Don’t assume that everything needs to be done by the maintenance team. Other teams may be more appropriate for the tasks, including:

•   Other IT teams

•   The business unit (the customer)

Figure 6-1: Service Breakdown Structure