Lag is the amount of time a successor activity is delayed after the completion of its predecessor activity. It represents a waiting period intentionally added to the schedule to account for necessary delays between tasks.
Key Aspects of Lag
- Delays Task Start – Prevents a successor activity from beginning immediately after its predecessor.
- Common in Construction & Manufacturing – Used when tasks require curing, drying, or waiting periods.
- Impacts Project Timeline – Affects the critical path and scheduling dependencies.
- Defined in Dependency Relationships – Often seen in finish-to-start and other logical relationships.
Example Scenarios
Construction Project
- Use Case: Concrete pouring requires a curing period before further work.
- Lag Applied: A 3-day delay before starting flooring installation.
Software Development
- Use Case: Backend API development must be completed before frontend integration.
- Lag Applied: A 1-week buffer to allow testing before UI work begins.
Event Planning
- Use Case: Promotional materials need time for printing before distribution.
- Lag Applied: A 5-day delay for production before marketing activities begin.
Why Lag Matters
- Ensures Proper Sequencing – Allows for natural delays where necessary.
- Prevents Premature Task Start – Avoids issues caused by overlapping activities.
- Affects Project Scheduling – Helps accurately define time dependencies.
- Optimizes Resource Allocation – Prevents idle time by planning necessary delays.
See also: Lead, Critical Path, Schedule Dependencies, Project Scheduling.