3 Project Scheduling and Time Management

Build the activity list

Start from the project’s deliverables and break the work into manageable activities. Each activity should describe a clear piece of work that can be assigned, estimated, and tracked; for example, “Draft user guide” is more specific than “Documentation.” Include important reviews, approvals, handoffs, and milestones.

Activities should be detailed enough to show meaningful progress without making the schedule needlessly complex. If a long task cannot be divided sensibly, use intermediate milestones to make its progress visible.

Sequence activities and find the critical path

Identify dependencies to determine the order of work. A predecessor must occur before its successor can start or finish. In a finish-to-start relationship, the successor starts after the predecessor finishes. Other relationships allow activities to start or finish together; use them only when they represent how the work will actually happen.

A network diagram makes these relationships visible. Schedule calculations can identify the critical path, the longest chain of dependent activities that determines the earliest possible project finish. Activities on this path have no scheduling flexibility, so a delay to one can delay the overall finish. Float, also called slack, is the time an activity can slip without delaying a specified successor or project finish.

Example: preparing a small product launch

Assume every dependency is finish-to-start and durations are in working days:

• Activity A: Confirm requirements; duration $2$; no predecessor.

• Activity B: Design packaging; duration $3$; predecessor A.

• Activity C: Order materials; duration $4$; predecessor A.

• Activity D: Assemble launch kits; duration $5$; predecessors B and C.

• Activity E: Inspect and release kits; duration $2$; predecessor D.

The two routes to completion take $2+3+5+2=12$ days for A–B–D–E and $2+4+5+2=13$ days for A–C–D–E. The critical path is A–C–D–E, so the earliest planned finish is day $13$. Activity B has one day of float: it can take one additional day before delaying D and the project finish.

Estimate activity durations

A duration is the working time expected to complete an activity, not necessarily the total elapsed time between its start and finish. Estimate duration from the work required, available people and equipment, their productivity, work calendars, and relevant experience or historical data. Record key assumptions so estimates can be reviewed and improved.

Common estimating approaches include:

• Expert judgment: Ask people familiar with the work to estimate it.

• Analogous estimating: Use the duration of a comparable past activity, adjusted for differences.

• Parametric estimating: Apply a rate to a quantity, such as hours per unit.

• Three-point estimating: Consider optimistic, most likely, and pessimistic durations. A common weighted estimate is $\frac{O+4M+P}{6}$, where $O$, $M$, and $P$ are the optimistic, most likely, and pessimistic estimates, respectively.

Use consistent time units and realistic calendars. Estimates should reflect the likely work rather than being shortened simply to fit a desired deadline.

Create and approve the schedule

Combine activity logic, duration estimates, milestones, calendars, and resource availability to calculate planned dates. A Gantt chart displays activities as bars across a timeline, while a network diagram emphasizes dependencies and paths. Both can help communicate the schedule, but meaningful dates and forecasts depend on the underlying logic.

Review the proposed schedule with the people doing the work and those responsible for key handoffs. Check that the critical path is sensible, resource constraints are reflected, and milestone dates are supported by the activities leading to them. Once approved, save the schedule as the baseline: the reference plan against which progress and changes will be assessed. Keep approved changes controlled and documented.

Track progress and forecast completion

At regular status intervals, record actual starts and finishes, work completed, and the remaining duration of unfinished activities. Compare current forecasts with the baseline to identify late activities or milestones and assess whether the project finish is at risk. Update network logic as well as dates: the schedule should forecast from actual progress rather than merely preserve old planned dates. Recheck the critical path because it can change as work proceeds.

Use objective evidence to assess completion, such as an approved design or a tested feature, rather than relying only on a vague percentage complete. For long activities, define intermediate deliverables or milestones. If the forecast slips, investigate the cause and consider realistic options, such as changing task order where safe, adding resources, adjusting scope, or revising the target date. Changes to the approved plan should follow the project’s change-control process.

The scheduling process brings together trackable activities, dependencies, realistic duration estimates, dates, and the critical path. After approving and preserving a baseline, update the schedule using actual progress and estimates of remaining work. Regular comparison with the baseline helps the team identify delays early and make informed adjustments.