Scheduling 101: how a construction schedule works, from the beginning

You can run a job without any of this

Plenty of good work gets run off a bar chart on the wall and a printed two-week list. Those are pictures of a plan, and there is nothing wrong with them. Reading a schedule the way the person who built it reads one is a different skill, and it is a smaller one than it looks.

Why it matters — nobody is born knowing what float is. It is a word with a plain meaning, and somebody has to say it out loud.

Twelve lessons, in an order

The order is not decoration. A new scheduling word is explained on the lesson that introduces it, and after that a lesson only borrows words earlier ones have already given you — so no scheduling word arrives undefined. Each lesson is also a page on its own: if you came here for a single word, take that one and leave.

The twelve lessons

The first five say what a schedule is and what it is made of. The next two say where its dates come from. The two after that say what it is telling you, and the last three say how to keep it true.

1. 01What is a construction schedule?What a schedule is a model of, and what that lets it answer that a drawing of one cannot.
2. 02What is an activity in a schedule?The pieces a schedule is built from, and what a duration is a statement about.
3. 03Why is five days not five days?Five working days is not always five calendar days — the non-working days on your job's calendar can move the finish.
4. 04What is a predecessor?The four ways two pieces of work can be tied together, and what a lag adds to one.
5. 05How do you read a Gantt chart?The bars, the arrows between them, and the shaded days the calendar does not count.
6. 06How does a schedule work out its dates?Forwards from a start date to find the soonest each piece can go, then back from the finish to find the latest it may run.
7. 07What is a constraint in a schedule?How to bound when work may start or finish, and when that bound overrides what the logic worked out.
8. 08What is float in a construction schedule?How much room a piece of work has before something else slips, the two things that room is measured against, and what a number below zero means.
9. 09What is the critical path?Why your finish date is computed rather than typed, which chain is driving it, and what driving means link by link.
10. 10What is a data date?What advancing it does, what "as of" means, and what happens when you enter a finish that has already passed.
11. 11Remaining duration or percent complete?Why Brikt asks the field for working days left, and how the percent you see is derived from it rather than typed.
12. 12What is a baseline schedule?Freezing a copy of the plan, so that how far the work has moved from it is a measurement rather than a feeling.

Where to start

If somebody handed you a schedule and asked you a question about it, start at the top. If you already read bar charts every week and want to know what the arrows between them mean, lesson five turns the picture you know into something you can read line by line. Either way you can stop and come back.

What is not in it

It teaches scheduling rather than this product. Where a lesson shows a Brikt screen it says so, and the idea is still the point. It also stops short of what a specialist needs: the shorthand for typing links, schedule quality checks and delay documentation are all real subjects, and none of them is here.

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What to remember

• Twelve short lessons, in an order, and each one also stands on its own.
• A new scheduling word is explained where it first appears, and after that a lesson only borrows backwards.
• The first five say what a schedule is and what it is made of; the next two, where its dates come from.
• The last five say what it is telling you, and how to keep it true.
• It teaches scheduling — where a lesson shows a Brikt screen, it says so.