Wednesday, January 14, 2015

Time Management - Tools and Techniques

Network diagrams:

  • Precedence diagramming method (PDM)
  • Arrow diagramming method (ADM)
  • Graphical Evaluation and Review Technique (GERT)
PDM is also known as Activity-On-Node (AON)


Four types of logical relationship between activities:

Finish to Start [FS] : Activity must finish before the successor can start.
Start to Start [SS] : An activity must start before the successor can start.
Finish to Finish [FF] : An activity must finish before the successor can finish.
Start to Finish [SF] : An activity must start before the successor can finish.  (rarely used)


Graphical Evaluation Review Technique [GERT]

Types of dependencies:
    Mandatory dependency (Hard logic)
    Discretionary dependency (preferred or soft logic)
    External dependency
Leads and Lags : Lead may be used to indicate that an activity can start before its predecessor activity is completed.   
Lag is inserted waiting time between activities.
Estimation   (important points)
  • Should be based on WBS
  • Should be done by the person doing work
  • Historical info 
  • Schedule, cost and scope baselines
  • Project schedule and budget
  • may periodically recalculate the estimate to complete (ETC)
Padding:  Guessing extra time or cost added to an estimate because of not enough info. (should not be followed)
Estimate Activity Resources:  Resources include equipment and materials as well as people
Estimate Activity Durations:
  •   Analogous estimating
  •   Parametric estimating
  •   Three-point estimating [PERT Analysis] : Optimistic(O), Pessimistic(P) and Most Likely (M)
    •     Expected activity duration (Beta distribution) = (P+4M+O)/6
    •     Expected activity duration (Triangular distribution) = (P+M+O)/3
    •     Activity Standard deviation = (P-O)/6
    •     Activity Variance = [(P-O)/6]^2
  •   Reserve Analysis : Contingency reserve & Management reserve
  •   One-point estimating
  •   Regression analysis : [Scatter diagram]
  •   Heuristics means rule of thumb
  •   80/20 rule : 80% of quality problems are caused by 20% of potential source problem.
Develop Schedule:
  • Compress the schedule by crashing, fast tracking and re-estimating
    • Crashing - if time must change, what option will cause the least impact on cost.  Crashing by definition, always results in increased costs.  
  • Simulate the project using Monte Carlo analysis to determine the likelihood of completing the project as scheduled
  • Level Resources if necessary
  • Schedule Network Analysis
    • Critical Path Method
    • Schedule compression
    • What-if scenario analysis
      • Monte-Carlo analysis uses computer software to simulate the outcome of a project, based on three point estimate.  Monte-Carlo analysis can help deal with "path convergence".  Monte-Carlo analysis also used as a risk management tool to quantitatively analyze risks.
    • Resource leveling - Leveling lengthens the  schedule & increase cost in order to deal with a limited amount of resources, availability and other constraints.
    • Critical chain method - take into account both activity and resource dependencies
Float (slack) : 3 types of float are :
Total float (slack):  Amount of time an activity can be delayed without delaying the project end date or an intermediary milestone.
Float & slack means the same thing.
Free Float (Slack) : Amount of time an activity can be delayed without delaying the early start date of its successor.
Project float (slack) : Amount of time a project can be delayed without delaying the externally important project completion date.

Activities on the critical path have zero float.

Float = Late Start(LS) - Early Start (ES)
Float = Late Finish (LF) - Early Finish (EF)


No comments:

Post a Comment