- 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)
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.
- 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)