What is the difference between a look-ahead and the master schedule?

Horizon and detail. The master schedule, built with the Critical Path Method, covers the whole project and is the contractual reference for dates and the critical path. It is too coarse to run a crew day to day. A look-ahead takes just the next few weeks of that master schedule and breaks the activities down to the level work is actually assigned, so a single master activity like "level 3 MEP rough-in" becomes the specific runs, rooms, and crews involved. The look-ahead does not replace the master schedule or change its logic; it is a working window pulled from it, refreshed every week, that turns the plan into something the field can execute.

Why three weeks, and when is six used?

Three weeks is the common horizon because it is long enough to see constraints coming while short enough that the detail is reliable. The near week is what the crews execute now, and the following two give time to remove constraints, order materials, chase an RFI answer, sequence a predecessor, before the work is due. Six-week look-aheads are used on larger or more complex jobs, or where long-lead materials and multiple trades need more runway to coordinate. The right horizon is the one that gives enough lead time to clear constraints without forecasting detail so far out that it is guesswork. Many teams run both: a six-week view for procurement and coordination and a three-week view for the work plan.

What is a constraint in look-ahead planning?

A constraint is anything that must be in place before an activity can start, and the whole point of the look-ahead is to find and clear them early. Typical constraints are materials on site, an approved submittal, an answered RFI, completed prerequisite work, available crew or equipment, permits, and safe access. In the planning meeting the team walks each upcoming activity and asks whether it is ready to go; an activity with an open constraint is not released to the weekly work plan until the constraint is removed. This practice, central to the Last Planner System, is why look-aheads reduce the stop-start churn of crews showing up to work they cannot actually do.

Construction Glossary · Scheduling

The Look-AheadSchedule

Crews do not build to a thousand-line master schedule. They build to the next three weeks of it, broken into real tasks with the constraints cleared.

Definition

A look-ahead schedule is a short-interval extract of the master schedule, usually three or six weeks, that shows the activities about to start or finish in the detail crews actually work to. It is the bridge between the CPM master schedule and the weekly work plan: in the planning meeting the team walks the near-term activities and confirms their constraints (materials, information, prerequisite work) are removed before an activity is allowed to start.

A window that slides every week

The look-ahead is a rolling window pulled from the master schedule. The activities inside it are broken down to crew-level tasks, and each is cleared of constraints before it is released to the weekly work plan.

From plan to work plan

The look-ahead sits between the contractual master schedule and the week the crews actually execute. Each horizon has a different job.

View	Horizon	Purpose
Master schedule (CPM)	Whole project	Dates, logic, the critical path
Six-week look-ahead	Six weeks	Procurement and trade coordination runway
Three-week look-ahead	Three weeks	Clear constraints before work is due
Weekly work plan	One week	Committed, constraint-free tasks for crews

How POD supports the near-term plan

POD reads the master schedule you import and renders a near-term look-ahead of the activities due to start or finish, so the next weeks are visible alongside the rest of the project record rather than buried in a scheduling file few people open. That lets the planning meeting work from a schedule everyone can see next to the field status. POD does not run the meeting, generate your look-ahead for you, or track constraint removal on its own; it surfaces the near-term window from the schedule the scheduling tool produced.

Construction scheduling software guide

Frequently asked questions

The window is punctuated by milestones

Inside every look-ahead are the checkpoints that mark real progress, the milestones the whole plan is sequenced around.

Milestone Back to the Glossary