CS Time Management (Part 9) Bilgisayar Mühendisliği Bölümü – Bilkent Üniversitesi – Fall 2009 Dr.Çağatay ÜNDEĞER Instructor Bilkent University, Computer Engineering Middle East Technical University, Game Technologies & General Manager SimBT Inc.

CS Time Management Project Management Components (knowledge areas) –Project Integration Management –Project Scope Management –Project Time Management –Project Cost Management –Project Human Resource Management –Project Communication Management –Project Quality Management –Project Risk Management –Project Procurement Management

CS Time Management Introduction Activity Definition Activity Sequencing Activity Duration Estimation Schedule Development Schedule Control

CS Time Management (Introduction) Includes the process required to ensure timely completion of project. Follows a “divide and conquer” strategy of breaking down a project into components that can be managed and controlled more easily. Once components are determined, –A sequence for doing the work tasks (schedule) is established, –Resources are assigned to those tasks, –Durations of tasks are estimated.

CS Time Management (Introduction) A project schedule generally created early in the project, –During initiation and planning. However, –Schedules are used in execution phases to help development; and –They will force development team to met some timing constraints (milestones).

CS Time Management (Introduction) Schedules (except some milestones) may frequently need to be updated as the project progress. As project moves forward, –Estimations become more accurate. This is reffered as cone of uncertainty [Barry Boehm 1981].

CS Time Management (Introduction) Cone of uncertainty: –A progressively more detailed and accurate projection of project schedule and duration as project deliverables and activities are specified in more detail. FeasibilityConcept Operation Requirements Specification Product Design Detail Specification Accepted Software Cone of uncertainty from Boehm

CS Time Management (Introduction) According to PMI; –At very early phases: Magnitude estimates: +75% -25%. –After components are specified in more details, budget is estimated: Budgetary estimates: +25% -10%. –When project resources and activities are highly detailed: Definite estimates: +10% -5%.

CS Time Management (Major Phases) Activity Definition: –Identifying specific activities that must be performed to produce project deliverables. Activity Sequencing: –Identifying and documenting interactivity dependencies. Activity Duration Estimation: –Estimating the number of work periods required to complete individual activities. Schedule Development: –Analyzing activity sequences, activity durations, and resource requirements to create a schedule. Schedule Control: –Controlling changes to project schedule.

CS Time Management Introduction Activity Definition Activity Sequencing Activity Duration Estimation Schedule Development Schedule Control

CS Activity Definition (Introduction) Involves identifying and documenting specific activities that must be performed to produce deliverables and sub-deliverables in work breakdown structures.

CS Activity Definition (Introduction) Work breakdown structures: –Deliverable-Oriented: Deliverables are listed in WBS. –Task-Oriented: Tasks to produce deliverables are listed in WBS.

CS Activity Definition (Introduction) If WBS is deliverable-oriented, –Activity definition generates activities for creating deliverables defined in WBS. –So output is called the activity list. If WBS is task-oriented, –Activity definition is performed in coordination with scope definition to determine both deliverables and tasks in WBS.

CS Activity Definition (Inputs) Work breakdown structure Scope statement Historical information Constraints Assumptions Expert judgement

CS Activity Definition (Inputs) Work breakdown structure: –A deliverable-oriented WBS Scope statement: –Contains project objectives. Historical information: –Historical information collected in previous projects could be helpful for doing estimations.

CS Activity Definition (Inputs) Constraints: –Factors limiting development options. Assumptions: –Factors that are accepted as true. Expert judgement: –Experts could be very useful in clarifying inputs.

CS Activity Definition (Tools & Techniques) Templates Decomposition

CS Activity Definition (Tools & Techniques) Templates: –An activity list from a previous project can be used as a template for the new project. –These templates, may also include; Resource skills and Required hours of effort for common activities.

CS Activity Definition (Tools & Techniques) Decomposition: –Involves sub-dividing project work packages into smaller components. –Final outputs should be described as activities, not as deliverables.

CS Activity Definition (Tools & Techniques) Decomposition: –Decompose an activity until the activity; Can be performed by one person or a well-defined group; Has a single, clearly identifiable deliverable; Has a known method or technique; Has well-defined predecessor and successor steps; Is measurable so that level of completion can be determined.

CS Activity Definition (Tools & Techniques) Decomposition: –Rolling wave planning: Often, activities for the next few steps can be planned at a sufficient level of detail. In this case, rolling wave planning technique is used. Closest activities are planned at a detailed level; Activities farther in the future are planned only at a general level.

CS Activity Definition (Outputs) Activity list Supporting detail Work breakdown structure updates

CS Activity Definition (Outputs) Activity list: –Includes all activities that will be performed within the project. –Should be an extention to WBS if a delivery-oriented WBS is used. –Should be clear enough to let team members understand the content.

CS Activity Definition (Outputs) Supporting detail: –Includes all identified constraint and assumptions, and other related details. Work breakdown structure updates: –Any missing deliverable identified during the activity definition should be integrated to WBS.

CS Time Management Introduction Activity Definition Activity Sequencing Activity Duration Estimation Schedule Development Schedule Control

CS Activity Sequencing (Introduction) Involves identifying and documenting interactivity logical relationships. Activities must be sequenced accurately to support later development of realistic and achievable schedule. In this phase, a network diagram will be generated to identify sequence.

CS Activity Sequencing (Inputs) Activity list Product description Mandatory dependencies Discretionary dependencies External dependencies Milestones

CS Activity Sequencing (Inputs) Activity list: –List of activities for producing deliverables. Product description: –Product characteristics may affect sequencing, –So they should be reviewed to ensure accuracy.

CS Activity Sequencing (Inputs) Mandatory dependencies: –Those that are inherent in the nature of work being done. –For instance, implementation should be started before testing. –Also called hard logic.

CS Activity Sequencing (Inputs) Discretionary dependencies: –Those that are defined by the project management team. –Should be used with care, Since they may limit later scheduling options. –Also called; Soft logic, Preferred logic or Preferential logic.

CS Activity Sequencing (Inputs) External dependencies: –Those that involve a relationship between project activities and nonproject activities. –For instance, programming language software should be delivered before implementation starts.

CS Activity Sequencing (Inputs) Milestones: –Deadlines that are forced by the stakeholders’ requirements. –Milestone events need to be part of activity sequencing to assure that requirements for meeting milestones are met.

CS Activity Sequencing (Tools & Techniques) Precedence diagramming method (PDM) Arrow diagramming method (ADM) Conditional diagramming method Network templates

CS Activity Sequencing (Tools & Techniques) Precedence diagramming method (PDM): –A method of constructing a project network diagram; That uses boxes or rectangles (nodes) to represent activities, and Connects them with arrows that show dependencies. A D BE F End C Start G Dummy node

CS Activity Sequencing (Tools & Techniques) Precedence diagramming method (PDM): –Has the ability to illustrate four types of task dependencies among activities. –Types of dependencies: Finish-to-start Start-to-start Finish-to-finish Start-to-finish

CS Activity Sequencing (Tools & Techniques) Precedence diagramming method (PDM): –Finish-to-start: One activity cannot start until another activity has been completed. For instance, programmers cannot start programming until programming language has been chosen. The most commonly used logical relationship type. P.L. chosenProgramming

CS Activity Sequencing (Tools & Techniques) Precedence diagramming method (PDM): –Start-to-start: The start of sucessor depends on the start of predecessor. For instance, programming cannot start until some portion of program design is decided on. Designing Programming

CS Activity Sequencing (Tools & Techniques) Precedence diagramming method (PDM): –Finish-to-finish: Completion of successor activity depends on the completion of the predecessor. For instance, testing a system cannot be finished until programming is completed. Programming Testing

CS Activity Sequencing (Tools & Techniques) Precedence diagramming method (PDM): –Start-to-finish: Completion of the successor activity depends on the beginning of the predecessor. For instance, backuping first version of code segment cannot be completed until programming begins. Rarely used. Programming Backuping code

CS Activity Sequencing (Tools & Techniques) Arrow diagramming method (ADM): –Another network diagramming technique that represents project activities as arrows and connects them at nodes to show their dependencies A = 2 B = 3 F = 2 C = 1 D = 1 E = 5 H = 5 I = 3 J = 4 G = 2

CS Activity Sequencing (Tools & Techniques) Arrow diagramming method (ADM): –Uses only finish-to-start dependencies. –May require use of dummy activities to define all logical relationships correctly A B D C E F Dummy activity

CS Activity Sequencing (Tools & Techniques) Conditional diagramming method: –Used for defining nonsequential activities such as conditional branches and loops. Perform testing Implementation Completed? Perform implementation Start implementation End implementation Yes No

CS Activity Sequencing (Tools & Techniques) Network templates: –Standardized networks can be used to accelarate preparation of network diagrams. –Portions of networks are offen reffered to as subnets or fragnets.

CS Activity Sequencing (Outputs) Project network diagram Activity list updates

CS Activity Sequencing (Outputs) Project network diagram: –May include full project details or have summary activities. –Any unusual sequence should be fully described. Activity list updates: –Activity definition process may generate updates to activity lists.

CS Time Management Introduction Activity Definition Activity Sequencing Activity Duration Estimation Schedule Development Schedule Control

CS Activity Duration Estimation (Introduction) Process of taking information on project scope and resources, and –Then developing durations for input to schedules. Inputs for estimates of a duration typically originate from person or group on project team who is most familiar with the nature of a specific activity. Estimates are often progressively elaborated.

CS Activity Duration Estimation (Introduction) Estimating number of work periods required to complete an activity will often require consideration of elapsed time. –Weekends and holidays should be considered. –For instance, If a task requires 3 days of work, but first day begins on Friday, Then elapsed time will be 5 days because of weekend.

CS Activity Duration Estimation (Inputs) Activity list Constaints Assumptions Resource requirements Resource capabilities Historical information Identified risks

CS Activity Duration Estimation (Inputs) Activity list: –List of activities for producing deliverables. Constaints: –Factors limiting the development options. Assumptions: –Factors that are accepted as true.

CS Activity Duration Estimation (Inputs) Resource requirements: –Duration of most activities will be significantly influenced by the resources assigned to them. –For instance; Allocating two people to a task may halve the time required to complete the task. Allocating a half-time person to a task may double the time required to complete task.

CS Activity Duration Estimation (Inputs) Resource requirements: –Increasing number of personnel assigned to a task does not necessarily mean reducing the time linearly. –Because additional resources will increase communication overload. –Also some tasks may not be performed in parallel.

CS Activity Duration Estimation (Inputs) Resource capabilities: –Duration of most activities will be significantly affected by the capabilities of human and material resources assigned to them. –For instance, assigning an experienced person to a task will reduce the time required to complete the task.

CS Activity Duration Estimation (Inputs) Historical information: –Likely durations of activities can be estimated from historical information. –Possible sources: Project files Commercial duration estimation databases Project team knowledge

CS Activity Duration Estimation (Inputs) Historical information: –Possible sources: Project files: –Records of previous projects that the organizations in the current project were involved in.

CS Activity Duration Estimation (Inputs) Historical information: –Possible sources: Commercial duration estimation databases: –Some historical information that could be available commercially (e.g. How long a governmental agency usually takes to respond to certain types of requests).

CS Activity Duration Estimation (Inputs) Historical information: –Possible sources: Project team knowledge: –Individual members of team may »Remember previous actuals or estimates, and »Use their experience. –These estimations are generally less reliable than documented results.

CS Activity Duration Estimation (Inputs) Identified risks: –Project team should consider identified risks when producing duration estimates. –Since risks can have significant influence on durations. –Revise baseline duration estimations for activities having risks with high probability of impact.

CS Activity Duration Estimation (Tools & Techniques) Expert judgement Analogous estimating Quantitatively based durations Reserve time (contingency)

CS Activity Duration Estimation (Tools & Techniques) Expert judgement: –Durations are often difficult to estimate Because of number of factors that can influence them. –Expert judgement should be used if possible, else it would be risky.

CS Activity Duration Estimation (Tools & Techniques) Analogous estimating: –Means using actual duration of a previous, similar activity as the basis for estimating duration of a future activity. –Also called top-down estimating. –A form of expert judgement.

CS Activity Duration Estimation (Tools & Techniques) Quantitatively based durations: –Quantities to be performed for each work category, when multiplied by productivity unit rate, can be used to estimate activity durations ( Quantity x Productivity ) –Quantities: e.g. number of drawings, number of functions. –Productivity unit rate: e.g. hours per drawing, hours per function.

CS Activity Duration Estimation (Tools & Techniques) Reserve time (contingency): –To reduce risks, Project team may add some extra time frame to risky activity durations or elsewhere in schedule. –This extra time is called; Time reserve, Contingency or Buffer. –Can be either in percentage or a fixed amount.

CS Activity Duration Estimation (Outputs) Activity duration estimates Basis of estimates Activity list updates

CS Activity Duration Estimation (Outputs) Activity duration estimates: –Should always include some indication of range of possible results. –For instance, With high probability, activity will take 2 weeks ±2 days.

CS Activity Duration Estimation (Outputs) Basis of estimates: –Assumptions made in developing estimates must be documented. Activity list updates: –Process may generate updates to activity lists.

CS Time Management Introduction Activity Definition Activity Sequencing Activity Duration Estimation Schedule Development Schedule Control

CS Schedule Development (Introduction) Means determining start and finish dates for project activities. Schedule development process must often be iterated a number of times prior to determination of final project schedule.

CS Schedule Development (Inputs) Project network diagram Activity duration estimations Resource requirements Resource pool description Calenders Constraints Assumptions Leads and lags Risk management plan Activity attributes

CS Schedule Development (Inputs) Project network diagram: –Shows activity sequencing. Activity duration estimations: –Shows number of work periods required for each activity. Resource requirements: –Include number of resources assigned to tasks.

CS Schedule Development (Inputs) Resource pool description: –Stores knowledge of what resources will be available at what times and in what patterns. –For instance, a shared or critical resources can be difficult to schedule Since their availability may be highly variable.

CS Schedule Development (Inputs) Resource pool description: –Amount of detail may vary in time. –For instance, For preliminary schedule, –One may only need to know number of consultants required. For final schedule, –One may need to know which specific consultants are required.

CS Schedule Development (Inputs) Calenders: –Project and resource calenders identify periods when work is allowed. –Project calenders affect all resources (e.g. 5 day work in a week). –Resource calenders affect a specific resource or a category of resources (e.g. A staff may be on vacation, a half-time staff).

CS Schedule Development (Inputs) Constraints: –Factors that will limit the development options. –Major time constraints: Imposed dates Key events or milestones

CS Schedule Development (Inputs) Constraints: –Major time constraints: Imposed dates: –Restrics activities as to; »Start no earlier than a specific date or »Finish no later than a specific date.

CS Schedule Development (Inputs) Constraints: –Major time constraints: Key events or milestones: –Completion of certain deliverables by a specific date may be requested »By customer, sponsor or Other stakeholders. –Once scheduled, »These days become expected, and »Often may be moved with great difficulty.

CS Schedule Development (Inputs) Assumptions: –Factors that are accepted as true.

CS Schedule Development (Inputs) Lead time: –Time required by one task before another task can begin. –For instance, in start-to-start relation, Testing can only be started after some portion of code is implemented. Implementation Testing Lead time Development Quality Inspection Lead time

CS Schedule Development (Inputs) Lag time: –Time delay between completion of one task and start of its successor. –For instance, in finish-to-start relation, Testing can only be started after implemention and compiling code are completed. Implementation Testing Lag time (Compiling)

CS Schedule Development (Inputs) Risk management plan: –A plan for detecting, monitoring risks and minimizing their impacts. Activity attributes: –Attributes of activities including; Responsibility (who), Geographic area or building (where), WBS classification (which branch), Activity type (other details),

CS Schedule Development (Tools & Techniques) Matematical analysis Duration compression Simulation Resource leveling Project management software Coding structure

CS Schedule Development (Tools & Techniques) Matematical analysis: –Involves calculating; Theoretical early and late start and finish dates for all project activities –Without regard for any resource pool limitations. –Result is not a schedule, But indicate time periods within which activity could be scheduled –Given resource limits and other known constraints.

CS Schedule Development (Tools & Techniques) Matematical analysis: –Most widely known techniques: Critical path method (CPM) Graphical evaluation and review technique (GERT) Program Evaluation and Review Technique (PERT)

CS Schedule Development (Tools & Techniques) Matematical analysis: –Critical path method (CPM): Calculates a single, deterministic early and late start and finish date for each activity; Based on deterministic network logic and duration estimates Early start D = 1 Late start Early finish Late finish

CS Schedule Development (Tools & Techniques) Matematical analysis: –Graphical evaluation and review technique (GERT): A network analysis technique that allows probabilistic network logic and duration estimates. Nowadays, not considered as a generally accepted and used scheduling technique.

CS Schedule Development (Tools & Techniques) Matematical analysis: –Program Evaluation and Review Technique (PERT): Uses a weighted average duration estimate to calculate activity durations. Nowadays, seldomly used.

CS Schedule Development (Tools & Techniques) Matematical analysis: –Program Evaluation and Review Technique (PERT): Optimistic, most likely and pessimistic durations are used.

CS Schedule Development (Tools & Techniques) Duration compression: –A special case of mathematical analysis; That looks for ways to shorten project schedule. –Techniques: Crashing Fast tracking

CS Schedule Development (Tools & Techniques) Duration compression: –Crashing: Dedicating extra resources to an activity in an attempt to finish activity sooner than its normal schedule. For example, hiring an extra personnel for an activity.

CS Schedule Development (Tools & Techniques) Duration compression: –Fast tracking: Means performing activities in parallel that would normally be done in sequence. For instance, –Starting to write code before design is completed. Often results in rework and usually increases risks.

CS Schedule Development (Tools & Techniques) Simulation: –A process of calculating different scenarios and their effects on the project schedule. –Scenarios, Project and activity durations, are generated using different assumptions, constraints and resource allocations.

CS Schedule Development (Tools & Techniques) Simulation: –Common used types are: Monte Carlo simulations What-if analysis.

CS Schedule Development (Tools & Techniques) Simulation: –Monte Carlo simulations: Probabilistic analysis used to calculate a distribution of likely results. In our case, we analyze likely task and project durations.

CS Schedule Development (Tools & Techniques) Simulation: –What-if analysis: A process of evaluating alternative scenarios –By observing how changes to selected factors affect other factors and outcomes. For instance, asks “what if a major component for a system is delayed”.

CS Schedule Development (Tools & Techniques) Simulation: –What-if analysis: Tries to assess the feasibility of schedule under unsuitable conditions. Helps preparing contingency/response plans for risks.

CS Schedule Development (Tools & Techniques) Resource leveling: –Any form of network analysis where resource management issues drive scheduling decisions.

CS Schedule Development (Tools & Techniques) Resource leveling: –Matematical analysis produce early-start schedules, But these schedules may not be feasible during some periods of time because of high resource requirements that exceeded available amount within the project. –Resource leveling techniques reschedule activites in order to reduce resource requirements.

CS Schedule Development (Tools & Techniques) Resource leveling: –For instance, If we have one person and two tasks that were scheduled at the same time, Resource leveling may push one of the tasks further in the future. Implementing A Implementing B Implementing A Implementing B Initial scheduleResource leveled schedule

CS Schedule Development (Tools & Techniques) Resource leveling: –Allocate scare resource to critical path activities first approach can be applied; To develop a schedule that reflects such contraints. –Often results in a project duration longer than the preliminary schedule.

CS Schedule Development (Tools & Techniques) Project management software: –Widely used to assist with schedule development. –These products automate calculation of matematical analysis and resource leveling, –Therefore allow rapid consideration of schedule alternatives.

CS Schedule Development (Tools & Techniques) Coding structure: –Use coding structures to help identifying, sorting, categorizing activities. –For instance, Code: –Project phase, –Activity responsibility, –Schedule level, etc.

CS Schedule Development (Outputs) Project schedule Supporting detail Schedule management plan Resource requirement updates

CS Schedule Development (Outputs) Project schedule: –Includes at least planned start and expected finish dates for each activity. –Remains preliminary until resource assignments are confirmed.

CS Schedule Development (Outputs) Supporting detail: –Includes at least documentation of all identified constraints and assumptions. –For instance; Resource histograms Alternative schedules Schedule contingency reserves

CS Schedule Development (Outputs) Schedule management plan: –Defines how changes to schedule will be managed. Resource requirement updates: –Resource leveling may have significant effects on resource requiements.

CS Time Management Introduction Activity Definition Activity Sequencing Activity Duration Estimation Schedule Development Schedule Control

CS Schedule Control (Introduction) Influencing factors that create schedule changes to ensure that changes are agreed upon. Determining that schedule has changed. Managining actual changes when and as they occur. Should be integrated with other control processes (e.g. integration change control, scope change control...).

CS Schedule Control (Inputs) Project schedule Performance reports Change requests Schedule management plan

CS Schedule Control (Inputs) Project schedule: –The approved project schedule is called the schedule baseline. –Basis for measuring and reporting project performance. Performance reports: –Provide information on schedule performance. –For instance, which dates have been met and which have not.

CS Schedule Control (Inputs) Change requests: –May occur in many forms –May require extending schedule or –May allow accelerating it. Schedule management plan: –Defines how changes to schedule will be managed.

CS Schedule Control (Tools & Techniques) Schedule change control system Performance measurement Additional planning Project management software Variance analysis

CS Schedule Control (Tools & Techniques) Schedule change control system: –A system that defines procedures by which project schedule may be changed. –Includes tracking systems, paperwork... Performance measurement: –Any technique to asses magnitude of variations that occur. –Helps to decide if schedule variations requires corrective actions.

CS Schedule Control (Tools & Techniques) Additional planning: –If any changes are required on schedule, Includes revising activity durations, activity sequences, and alternative schedules.

CS Schedule Control (Tools & Techniques) Project management software: –Very useful for; Tracking planned dates versus actual dates, Forecasting effects of schedule changes.

CS Schedule Control (Tools & Techniques) Variance analysis: –During schedule monitoring, regularly performing variance analysis is important. –Includes comparison of planned and actual or forcast start and finish dates In order to see affects of variations. –Particular attention should be given to critical and sub-critical activities.

CS Schedule Control (Outputs) Schedule updates Corrective actions Lessons learned

CS Schedule Control (Outputs) Schedule updates: –Any modification to schedule information. –Approved schedule updates are called revisions. Corrective actions: –Anything done to bring expected future performance in line with baseline schedule.

CS Schedule Control (Outputs) Lessons learned: –Causes of variances, –Reasoning behind corrective actions, –Other types of lessons learned should be documented for the future use.