Learn · Scheduling 101
What a schedule is: a model of the work, not a list of dates
After this subject you can say what a schedule models, why the order of the work is the part a model can reason over, and what a model can answer that a printed plan cannot.
You already have a plan. This is what a schedule adds
Most jobs run off a plan somebody drew: a wall chart, a printed sheet, a spreadsheet of dates. It says when things are meant to happen. What it cannot do is answer a question — move one thing and the sheet does not tell you what else moves, because paper does not work anything out.
So what is a schedule, exactly?
A schedule is a model of the work: the pieces, how long each one takes, and the order they have to happen in. That is the difference. A printed plan records an answer; a model holds enough of the reasoning behind that answer to be asked for a new one.
Why it matters — everything else in this course is a piece of that model. This is the sentence the rest hangs on.
Some of it cannot move
Some work cannot start until other work is done. A slab is poured before a wall stands on it; a wall closes before it is painted. Written down once, that ordering is the part a model can reason over — together with the other things the next lessons add.
The question a drawing cannot answer
Tell a printed sheet the steel is two weeks late and it says nothing back — it is a picture of one answer. Put the same two weeks into the model, work it out again, and it tells you what that delay reaches, which is sometimes less than you feared.
Why it matters — this is the return on writing the order down, and it is the one you feel on a bad week.
The questions a model lets you ask
Ask
What is this waiting on?
Instead of
When is this supposed to start?
Ask
If this runs two weeks late, what else moves?
Instead of
Are we still on for the end of the month?
Ask
What has to be true for that date to hold?
Instead of
Can we hit that date?
What the model asks of you in return
A model is only as good as what goes into it. It starts with the pieces of work named, an honest estimate of how long each one takes, and the order they have to happen in. The lessons after this one add what else the dates depend on. Each piece is plain enough; keeping the whole thing honest takes care.
Why it matters — you reason it out once. After that, every time you tell it something has changed, it can do the arithmetic again for you.
What to remember
- A schedule is a model of the work, not a picture of one answer.
- Some work cannot start until other work is done, and writing that down is what makes the rest possible.
- A printed plan records dates; a model can be asked what happens when one of them moves, and worked out again.
- It starts with three things — the pieces named, how long each takes, the order they go in — and the next lessons add the rest.
Write down what one week is waiting on
Take one week of work off the plan you are running now and, beside each piece, write what it is waiting on — and "nothing" where nothing is holding it, which is a real answer too. That short list is the beginning of a model, and everything the rest of Scheduling 101 adds is built on it. If you would rather see it done on a real job first, bring your plan to a demo and we will build the first week together.