The Look-Ahead is the bridge between the master schedule and the work week. It is where the plan stops being theory and becomes concrete field commitments. We explain how to implement it, what information to capture and how to use it in site meetings so that the delay does not catch you by surprise.
What is Look-Ahead Planning?
The Look-Ahead, or intermediate planning, is a rolling window of 3 to 6 weeks that branches off from the master schedule. While the master schedule lives in months and milestones, the Look-Ahead drills down to the detail of what is coming up "now": the activities of the next few weeks, their requirements and their constraints.
It is part of the Last Planner System, the Lean Construction planning methodology. Its logic is simple and powerful: you can only promise to do what is free of constraints. The Look-Ahead is the mechanism to identify and release those constraints before the activity has to start.
| Level | Horizon | Question |
|---|---|---|
| Master Plan | The whole project | What should happen? |
| Look-Ahead | 3 to 6 weeks | What can happen (free of constraints)? |
| Weekly Work Plan (WWP) | 1 week | What are we going to do (committed)? |
The central idea: the master schedule says what should be done. The Look-Ahead filters that through reality (do I have the material, the approved drawing, the released work front, the crew?) and only lets through to the weekly plan what truly can be executed. This is how you protect the workflow from empty promises.
Constraints: the heart of the method
A constraint is anything that prevents an activity from being able to start. The typical categories on site:
- Design: an unapproved drawing, a pending construction detail, an unanswered RFI.
- Materials: steel, formwork or equipment that has not yet arrived on site.
- Labor: a crew that is not available or does not have the required specialty.
- Work front / prerequisite: the preceding activity has not finished and released the work front.
- Permits / external: a municipal permit, an inspection, client authorization.
Each Look-Ahead activity is analyzed against this list. If it has constraints, an owner and a deadline are assigned to release them. That list of constraints with an owner and a date is the true deliverable of the Look-Ahead.
How to implement it step by step
Explode the master schedule into the window
Take the schedule activities that fall in the next 3 to 6 weeks and break them down to an executable level of detail (by work front, by crew, by daily task if needed).
Analyze the constraints of each activity
For each task in the window, review the constraint categories. Mark what is missing. An activity with no constraints is "ready" (sound) to enter the weekly plan.
Assign an owner and a date to each constraint
"The detail drawing for the diaphragm wall is missing → owner: technical office → deadline: Friday." Without an owner and a date, an identified constraint does not release itself.
Follow up weekly in the meeting
Each week, the window advances one week: new activities enter at the back and those already being executed drop out. The status of the constraints is reviewed and only what is "sound" passes to the weekly commitment.
Look-Ahead and the PPC indicator
The Look-Ahead feeds the weekly plan, and the weekly plan is measured with the PPC (Percent Plan Complete): of what you promised to do this week, how much did you deliver? When the Look-Ahead works and filters constraints well, the PPC rises, because you only commit to what you could truly do. A chronically low PPC almost always means that work is being committed with constraints that have not been released.
Practical tip: measure and publish the "reasons for non-completion" each week. If 60% of the failures come from "material not available", the problem is not in the crew: it is in logistics and procurement. The Look-Ahead doesn't just anticipate: it tells you where the real leak is.
The most common mistake
Treating the Look-Ahead as just a more detailed schedule and nothing more. The detail is worthless if there is no constraint analysis with owners and follow-up. A Look-Ahead without constraint management is just a pretty list of tasks that will fall behind anyway. The value is in releasing constraints, not in scheduling with more decimals.