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Project Time Management
PMBOK Guide 葉明導讀
Project Time management l 專案時間管理是專案管理中最旗幟鮮明的領域， 其中的甘特圖 (Gantt Chart) 已然成了專案管理的圖騰。時程 (Schedule) 的制定完成，是專完案計畫階段的重大里程碑，而時程管制 (Schedule Control) 則是專案執行階段最重要的工作之一。 n To accomplish timely completion of the project n Process include 1. Activity Definition 2. Activity Sequencing 3. Activity Resource Estimating 4. Activity Duration Estimating 5. Schedule Development 6. Schedule Control
Activity Definition l 活動定義是將工作包 (Work package) 再予以分解成為活動 (Activity)。工作包代表交付物的層級，活動則是工作項目的層級，用以產出交付物。 n Identifies the specific schedule activities that need to be performed to produce the various project deliverables n Decompose work package into smaller components call schedule activities n Planning Process Group
Activity Sequencing l 活動排序就是把各項活動的依存間係，用網狀圖來表現，重點在於產出網狀圖的各種知識及技術。 n Identifies and documents dependencies among schedule activities n Creates project schedule network diagram n Planning Process Group n Tools and Techniques l Precedence Diagramming Method (PDM) l Arrow Diagramming Method (ADM) l Dependency Determination l Applying Leads and lags
Logical Relationship l 或稱 Precedence relationship / dependency， 指兩活動間的相互依存關係，並可搭配 Lead / Lag 的條件使用。 n Includes l FS : Finish-to-Start l FF : Finish-to-Finish l SS : Start-to-Start l SF : Start-to-Finish
Precedence Diagramming Method (PDM) l 優先順序圖示法是一種網狀圖 的表示方法，用節點來表示活動。 n A tool of Activity Sequencing n Also called activity-on-node (AON) n Uses boxes or rectangles (nodes) to represent activities n Use arrows to show dependencies n Includes FS, FF, SS, SF
Arrow Diagramming Method (ADM) l 箭號圖示法是一種網狀圖 的表示方法，用箭號來表示活動。 n A tool of Activity Sequencing n Also called activity-on-arrow (AOA) n Uses arrows to present activities n Connects activities at nodes to show their dependencies n Uses only FS n Dummy activities could be required n Duration of a dummy activity is zero
Dependency l 依存關係即邏輯關係，另一種分類方式如下所述。 n Types include l Mandatory dependency: hard logic, the nature of work l Discretionary dependency: preferred logic, preferential logic or soft logic, l External dependency: between project activities and non-project activities
Lead l 活動間的依存關係不會剛好都是FS / FF / SS / SF， 可能允許提前 (Lead)，或是必須延後 (Lag)。 n A modification of a logical relationship that an acceleration of the successor activity
Lag l 不要把 Lag 當作 Delay 或是 Reserve， 這些都是極大的誤解。 n A modification of a logical relationship that directs a delay in the successor activity n Waiting time
Project Schedule Network Diagram l 這個階段的網狀圖，只有顯示活動間的依存關係， 並不包含各活動的工期。網狀圖在職埸上常被稱為 PERT 圖，與 PERT 的原意不盡相同，須注意曲分。 n Schematic displays of the project schedule activities and the logical relationship among them n A output of Activity Sequencing
Activity Resource Estimating l 活動工期的長短，與投入資源的型式及多寡有關，故須先進行資源估算。 專案管理的估算流程，另有 Activity Duration Estimating 及 Cost Estimating。 n Estimates the type and quantities of resources required to perform each schedule activity n Planning Process Group n Tools and Techniques include l Expert Judgment l Alternative analysis l Published estimating data l Project management software l Bottom-up estimating
Activity Duration Estimating l 估算各項活動的工期，以便進行 Schedule 制訂。 n Estimates the number of work periods that will be needed to complete individual schedule activities n Planning Process Group n Tools and Techniques include l Expert judgment l Analogous estimating l Parametric estimating l Three-Point estimating l Reserve analysis
Analogous Estimating l 類比估算 需要經驗，快速、成本低是其優點，較不精確是其缺點。 n Also called top-down estimating n A form of expert judgment n Uses historical information
Three-Point Estimates l PERT採用這種估算方式，是對單一估算 值的一種改進，以提高估算的精確 度。 n Most likely, Optimistic, Pessimistic n PERT estimate: (P+4M+O)/6 n PERT Standard deviation: (P-O)/6
Schedule Development l 專案時間管理在計劃階段的終極目標，便是制訂出專案時程。繁 複的工具及技術， 都是為了能規劃出合理可行的時程，做為執行及監控專案工作的依據。 n Analyzes activity sequences, durations, resource requirements, and schedule constraints to create the project schedule n Planning Process Group n Tools and Techniques include l Schedule Network Analysis l Critical Path Method l Schedule Compression l What-If Scenario Analysis l Resource Leveling l Critical Chain Method l Project Management Software l Applying Calendars l Adjusting Leads and Lags l Schedule Model
Critical Path Method (CPM) l 要徑法是規劃專案時程的必備技術及知識，是 由美國杜邦公司發展出來的。 n The longest duration through a network diagram n The shortest time to complete the project n Forward pass: calculates the early start and finish dates for all schedule activities. n Backward pass: calculates the late stare and finish dates for all schedule activities n Critical paths have either a zero or negative total float n A critical path can run over a dummy n There can be more than one critical path n More critical paths increase the project risk
Float l 浮時是要徑法最在意的掌控元素。 n Also called slack n Calculated using the CPM n Provides the schedule flexibility n Free float: the amount of time that a schedule activity can be delayed without delay the early start of any immediately successor schedule activity n Total float: the total amount of time that a schedule activity may be delay from its early start without delaying the project finish date
Schedule Compression l 壓縮時程有趕工及快速跟併兩種方法，各有利弊，須明辨。 n Includes Crash and Fast Tracking n Crash l A schedule compression technique l Results in increased cost n Fast Tracking l A schedule compression technique l Phases or activities that normally would be done in sequence are performed in parallel l Result in rework and increased risk
Monte Carlo Analysis l 蒙地卡羅分析是一種模擬分析技術，亦可分析風險。 n A technique of simulation n A distribution of possible activity durations is defined for each schedule activity n Calculates a distribution of possible outcomes for the total project n Gets an indication of the risk involved in the project
Resource Leveling l 資源撫平是考慮資源的限制及有效利用，而對要徑法產出的時程所作的調整。 n Also called resource based method n Applied to a schedule model that has already been analyzed by the critical path method n Keeps selected resource usage at a constant level during specific time periods n Results in a longer schedule n Resource reallocation from non-critical to critical activities to bring the project back on track n Produces a resource-limited schedule, some timed called resource-constrained schedule
Critical Chain Method l 關鍵鏈是 Eliyahu M. Goldratt 所提出的時程規劃方法，也是其所著企管小說的書名。 n Modifies the project schedule to account for limited resource n Uses non-conservative estimates for activity durations n Adds duration buffers that are non-work schedule activities n Focuses on managing the buffer activity durations and the resources applied to planned schedule activities
Project Schedule l 專案時程可用三種述圖表來表現， 應視其需要來選用。 n Formats include l Project Schedule Network Diagrams: To show interdependencies between tasks l Bar Charts (Gantt Chart): To track progress, report to the team l Milestone Charts: To report to senior management; there is no duration of a milestone
Schedule Control l 專案進度的量測、 變異的分析、時程的掌控、變更的管制。 n Controls changes to the project schedule n Monitoring & Controlling Process Group
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