How do you define and manage lag and lead time in dependency-driven scheduling

Question

When you’re setting up schedules with task dependencies, how do you usually define and manage lag and lead time so the plan stays realistic?

Answer 1

Lag and lead are time differences between dependent tasks that affect their start and end relationships. They are used to model real-world timing restrictions in scheduling logic.

• Lag Time – The delay between dependent tasks

  • Added when there is a required gap following a predecessor job

  • Example: FS+2 signifies successor starts 2 days after predecessor stops

  • Frequently used in building, manufacturing, and phased processes

• Lead Time – Acceleration or overlap between tasks

  • Allows a successor to begin before the predecessor ends

  • For example, FS-3 indicates that the successor begins three days before the predecessor finishes

  • Effective for Agile, design-development overlaps, or content-approval loops

• Managing Lag and Leading in Scheduling Tools

  • In tools like MS Project, Primavera, and Smartsheet, add lag/lead using dependency fields

  • Clearly define the rationale for lag/lead in WBS notes or task descriptions

  • Use these cautiously, as large or arbitrary leads/lags diminish schedule clarity and flexibility

Lead and lag help model realistic time gaps or overlaps and should be applied deliberately.