Memory Sheets Flashcards
Forward Pass
The Early Start (ES/top-left) of first task is 1.
The Early Finish (EF/top-right) is: ES+Duration (top middle)-1.
The ES of the next task is: Previous EF+1.
The EF for the next task is: ES+Duration-1.
The EF with the largest value is carried forward.
Backward Pass
This starts at the end of the PND.
The Late Finish (LF/bottom-right) for the last activity equals its EF value.
The Late Start (LS/bottom-left) is: LF-Duration+1.
The next predecessor’s LF equals: Successor LS-1
Calculate Float
Float/bottom-middle = [ES/top-left]-[LS/bottom-left]
Lag
Waiting time between activities (positive)
Lead
Activities are moved closer together or overlap (negative)
Crashing
Adding resources to reduce the project duration. Adds cost.
Fast tracking
Allows project phases to overlap to reduce the project duration. Adds risk.
Free float
The amount of time an activity can be delayed without delaying the next activity’s start date.
Total float
The amount of time an activity can be delayed without delaying the project’s end date.
Finish-to-start (FS)
The relationship means Task A must complete before Task B can begin. Most common.
Start-to-start (SS)
This relationship means Task A must start before Task B can start. This allows both activities to happen in tandem.
Finish-to-finish (FF)
This relationship means Task A must complete before Task B. Ideally, the two tasks must finish at exactly the same time.
Start-to-finish
Rarely used. It requires Task A to start so that Task B may finish. It is also known as JIT or Just In Time scheduling.
Planned Value (PV)
What the project should be worth.
Earned Value (EV)
What the project is worth.
EV = % Complete x BAC
Actual Cost (AC)
What the project has spent so far.
Budget at Completion (BAC)
What the project budget is.
Cost Variance (CV)
The difference between EV and AC.
CV = EV - AC
Positive is under budget.
Negative is over budget.
Schedule Variance (SV)
The difference between earned value and planned value.
SV = EV - PV
Positive is ahead of schedule.
Negative is behind schedule.
Variance at Completion (VAC)
Projection of being over or under budget based on current performance.
VAC = BAC - EAC
Positive is under budget.
Negative is over budget.
Cost Performance Index (CPI)
Shows overall cost efficiency on the project.
CPI = EV / AC
Greater than 1 is under budget.
Less than 1 is over budget.
Schedule Performance Index (SPI)
Shows overall schedule adherence.
SPI = EV / PV
Greater than 1 is ahead of schedule.
Less than 1 is behind schedule.
Estimate at Completion (EAC) - Standard
Forecasts final project costs based on current performance.
EAC = BAC / CPI
Estimate at Completion (EAC) - Future work at planned costs
Forecasts final project costs based on current performance.
EAC = AC + BAC - EV