Project management in-depth understanding of 04--time Management

Source: Internet
Author: User

Into the more important time management chapter, focus on the WBS, work units, activities, resources, time this clue understanding, stay up late to 4 points, continue my study, just wait for the state of the data, refueling, Kumaji.

    • Network Diagram, PDM,CPM and other technologies, critical path, floating time

PDM: Precedence Diagramming method in the pre-close relation drawing

other name

node notation


node represents activity, arrow line indicates dependency


4 kinds: Finish-start FS, Finish-complete FF, start-start SS, start-Complete SF


Show project activity and its logical relationship

The CPM critical path method critical the path method to calculate the earliest, latest start and finish times of the project without regard to any resource constraints.

Floating time: It is the amount of time that an activity can be deferred without affecting the completion of the project, which indicates that the activity will be delayed when the floating time is negative, and the associated activity time is the following table.

earliest start time early start, ES

earliest finish early finish, EF

latest start time, last start, LS

Last finish, Lf

free float time freely float, FF

Total float time, all float, TF

scheduled start time schedule start, SS

scheduled finish schedule finish, SF

Actual start time actually start, as

Actual completion time actually finish, AF

Total floating time TF: Is the difference between the latest and the earliest time of a progress activity ; The free float time FF is the difference between the earliest start time of a tight post activity for a progress activity and the earliest end time of the activity.

    • How to use PDM to make a network diagram, see the M.F.B. S chapter of the project.
    • Scheduling adjustments when resource constraints are in progress

The CCM key chain method, which is limited in resources, is a resource-constrained schedule, which combines deterministic and random methods in the progress network analysis and often changes the critical path of the project. It uses the steps to draw a progress Network Diagram, calculate the critical path, determine the resource constraints schedule based on the resource situation, add a duration buffer segment in the Progress Network diagram, and determine the buffer plan activity that can be scheduled by the latest start time and the late finish.

Resource Optimization Technology: Resource Balance method, used in the progress model which has been analyzed by the critical path method, using Resource table, Resource Gantt Chart, resource histogram, resource control schedule, time constraint schedule and other tools; scatterers smoothing, which does not change the key chain and the project final completion time, Activities are adjusted only within their free float time and total floating time.

Tip: Resource balancing is a way to reduce the allocation of resources and allocate resources on non-critical paths to critical paths.

By adjusting the front and back tasks, you can make the whole network lie more flexible and operational.

    • Monte Carlo analysis-the most common method of simulation

Modeling techniques include: Hypothetical scenario analysis, simulation, the most commonly used simulation technique for Monte Carlo analysis, and the main point is that multiple simulations can produce a range of possible results and the probability of each result, the results may be more pessimistic than the three-point estimate and CPM.

    • Progress compression method: Rush, fast follow-up and corresponding impact

The progress compression method is used in the key chain activities, which can shorten the project history without changing the project scope, and re-check the critical path after compression, the common way is as follows.

Rush: Refers to the consideration of overtime and other methods, the cost and progress of the trade-offs, to determine the minimum increase in costs under the premise of minimizing the duration of the project, to drive trade unions to increase costs, and not always effective.

Fast Follow-up: Refers to the sequential execution of planned activities in the original order, and rapid follow-up increases the risk of rework, often resulting in increased risk.


WBS is for deliverable success, the grouping of project elements, activities is the production of deliverables, activities can be subdivided into multiple tasks, activities require resources and duration, the task is like the lowest level of work in the project, for specific industries, application areas.

Common project management software includes: Primavera P6, IBM RPM, Visual project, MS project.

    • Project Time Management : Time, scope, cost, together constitute the three elements of the project, the whole process can be understood as, in the schedule management plan, on the basis of the WBS, based on the completion of the work package requirements, the completion of the project must be And does not contain all unnecessary activities, then analyzes the logical relationships between activities , estimates the activity resources and durations, formulates schedules and supervises the approved progress benchmarks.

Planning process

Monitoring process

Planning Progress Management

Defining activities

Arrange activity Order

Estimating Activity Resources

Estimated activity duration

Make a progress plan

Control progress

TIP: Effective time management is one of the key issues in project management, and the scheduling problem causes the most conflicts within the project life cycle.

    • Basic terminology

Activity activities: A unit of work in a project process that consumes time and resources and is usually subdivided into task tasks.

Task tasks: Is the lowest level of the project work, for specific industries, application areas.

Human input effort: The number of labor units required to complete a planned activity and WBS component, often in person, day, or week.

Discrete input, can directly identify its contribution, and can be intuitive planning and measurement of work input, that is, non-continuous work of human input, allocation of input, not easy to decompose, but with measurable discrete work input proportional to human input, such as QA work.

Input level of effort, a means of measuring ancillary work that is not easy to measure with apparent achievement.

Duration, the total number of work hours required to complete the planned activity or WBS component.

Events, specific events that occur in the life cycle of a project, you can try a particular activity, a meeting or a deliverable submission, and no resources are required.

Milestone Milestone, a major event or point in a project, usually refers to the completion of a major deliverable.

Activities see dependencies, activity sequencing must be related to milestones: Mandatory dependencies, selective dependencies, external dependencies, internal dependencies, logical relationships, tight-forward relationships, and understanding the concepts of advance and lag quantities.

Planning Progress Management : It is a further refinement of the project management in the management of symptoms.

Define activities : further decomposition and refinement of project work based on known information such as project scope statement, WBS, etc., in order to lay a good foundation for allocating resources, scheduling, estimating costs and monitoring projects. It is important to note that the final outcome defined by the definition activity is the planned activity, and the final outcome of the production WBS is a deliverable-based decomposition work package, which is often done by the project team members responsible for the work package, which is part of the project's schedule, not part of the WBS. The milestone list is part of the project file and is used for the progress model. The input is the schedule management plan, the scope datum (including the scope specification, WBS, WBS dictionary), the output is the activity list, the activity attribute, the milestone list.

arrange the sequence of activities: the process of identifying and documenting the logical relationship between activities, taking into account the activity's tight front/tight post relationships, and adding the amount of advance and lag as appropriate.

Estimating Activity resources: Determine the resource, quantity, and time to use when implementing project activities, which is closely related to the accuracy of cost estimates and the estimation of activity durations. The method includes alternative analysis, published estimation data, bottom-up estimation, etc., and its output is the activity resource demand and resource decomposition structure.

TIP Breakdown Structure Summary:

Work breakdown structure WBS: A deliverable-oriented work-level decomposition that defines the full scope of the project.

Organizational Breakdown Structure OBS: Hierarchical presentation of the project organization to clarify the responsibility of the work package.

Resource decomposition structure RBS: the hierarchy in which resources are categorized.

Risk decomposition Structure RBS: Displays the areas and causes of identified risks by hierarchy of risk categories.

Estimating activity Duration : Estimating the duration of a planned activity with information such as the scope of work, resource requirements, resource calendars, etc. of the previously acquired planning activity, which is more important than the relevant approach. Relevant methods include: expert judgment, analogy estimation, parameter estimation, three-point estimation, group decision-making technology, and reserve analysis.

Three-point estimate: From the planning review technical Pert, consider the most likely, optimistic, pessimistic three duration of the activity, respectively, expressed as M, O, P, using the distribution mean calculation.

Mean mean= (p+4m+o)/6,

Standard deviation &= (p-o)/6

Variance &2=[(p-o)/6]2,& total =

Next, through an example to learn, a project on the critical path of the activity c,d,e information on the following table, ask the project in 14.57 days to complete the probability?


Average History te

Standard deviation













Total Duration



Because 14.57-13.50=1.07, for a standard deviation, the probability of completion in 14.57 days is: 50%+1δ=50%+34.13%=84.13%.

(emphasis) to develop a schedule: This is an iterative process, which is consistent with the performance of the work, the change of plan and so on, to determine the start and finish dates and corresponding milestones of the project activity plan, and to be approved as a standard for tracking project progress performance. This part of an important input is the project Progress Network diagram, this common method includes the Progress network analysis method, the key path method, the key chain method, the resource optimization technology, the modelling technology, the advance quantity and the lag quantity, the progress Compression Progress Plan compilation tool and so on.

The output is: progress benchmarks, various ways of project scheduling (Gantt Chart, milestone map, Project progress Network diagram).

Control Progress: refers to the progress benchmark plan as a measure, record progress performance, management deviation. For project managers, time is more of a constraint, and efficient time management principles must be adopted to make it a wealth. The input includes project management plan, job performance data, project calendar, etc., tools including performance review, resource optimization technology, advance quantity lag, etc., output is job performance information, schedule forecast, change request, etc.

    1. Johnny Musan . successfully passed Pmp[m]. Beijing : Tsinghua University Press ,.

Project management in-depth understanding of 04--time Management

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