Page 287 - Six Sigma Demystified

Part 3 s i x s i g m a to o l s 267

whereas the other diverts to a secondary path. Note that these secondary paths
may result in a jump to a later point in the process (as shown in the first deci-
sion’s yes path) or to a prior point in the process (as shown in the second deci-
sion’s yes path). Decision paths and endpoints for processes, also may branch
to other process flowcharts, as indicated by the circle in the last step of this
process. In this example, the shaded symbols indicate external process steps.

gantt Chart

The Gantt chart is a tool to define the critical path for dependent tasks in a
project. The critical path consists of all activities, in order of occurrence, re-
quired as soon as possible to keep the project on schedule. Delay in any of the
critical task activities will result in slippage to the project’s completion date.
Tasks that are not on the critical path do not need to be completed as soon as
possible: They have slack time associated with them. Differentiating between
tasks on the critical path and those with slack time allows us to allocate our
limited resources most effectively.

When to Use

Define Stage

• To identify the critical path for cycle time reduction
• To identify project activities that determine the total project duration
• To identify and schedule all activities in the project (define through con-
trol stage)

Improve Stage

• To verify the reduction in process critical-path cycle time

Methodology

Begin by compiling a list of all the tasks that must be completed for the overall
project or process. Arrange these tasks in chronological order. Next, place all
the tasks in a progressing line. Depending on the project, you might be able to
work on some tasks simultaneously, whereas other tasks may depend on the
prior completion of tasks. Jobs that can be done simultaneously can be placed
on parallel paths, whereas jobs that are dependent should be placed in series. In