Scheduling Fundamentals, Terminology, and Standards
This domain checks whether you can use scheduling terms precisely and place a schedule within recognized standards. CAPES questions often hinge on definitions that look interchangeable but are not: activity versus event, total versus free float, schedule level versus schedule class, and constraint versus logic. Precise use of these terms is the foundation for calculation, analysis, and reporting.
Terms you must define without hesitation
- An activity is a discrete, time-consuming scope item; an event is a zero-duration milestone. A milestone can be a start or finish milestone, but it is not work.
- Duration is the working time required, expressed in the activity calendar. Elapsed time can be longer when calendars differ.
- A logic tie is a dependency (FS, SS, FF, SF); a lag or lead is a time offset on that tie; a constraint is a date restriction imposed on an activity, not a dependency.
- Total float = LS − ES or LF − EF. Free float = ES of the earliest successor − EF of the activity. Free float can never exceed total float on the same activity.
- The critical path is the longest path through the network and has the least total float-often zero, but negative when a constraint is missed.
Standards and classification
AACE International Recommended Practices are the common reference set: schedule classification (Classes 1–5), schedule levels of detail (37R-06), schedule basis documentation (38R-06), and identifying critical activities (49R-06). Classification reflects maturity and intended use, not simply the number of activities. A Class 5 schedule may be milestone-level or analogous; a Class 1 schedule is execution-ready and fully logic-linked. Schedule levels describe the summary-to-detail hierarchy for different audiences. Class and quality are separate judgments.
Worked example
Activities: A (3 days), B (4 days), C (6 days), D (3 days). A precedes B and C; both precede D. Path A–B–D = 3+4+3 = 10 days; A–C–D = 3+6+3 = 12 days. The critical path is A–C–D. For B: ES = 3, EF = 7, LS = 5, LF = 9, so total float = 2 days. D's ES = 9, so B's free float = 9 − 7 = 2 days. If a finish-no-later-than-day-8 constraint is placed on B, its LF becomes 8 and total float becomes −1 day, exposing a real logic or duration problem rather than a constraint benefit.
Traps that cost marks
Assuming free float and total float are the same; treating a constraint as a logic tie; using calendar days when the activity calendar is 5-day; and calling a summary bar a critical path. Also, a schedule can be Class 3 for bidding and still be poorly logic-linked-class and quality are different assessments.