Constraints and dates

Sometimes a date is a fact: a delivery, a contract. Here is how to tell the engine, and how not to.

Calendar and constraints holds an activity's dates: a primary constraint, its date, and a secondary one. Nine kinds. Most are a floor or a ceiling on a start or a finish; two are mandates.

Start on or after: the steel waits for its delivery. Type the date as month, day, year. A secondary constraint closes the other side: a floor and a ceiling on one activity.

In the grid, the Constraint and Constraint date columns show it: day, month name, year. Press F9: the engine honours the floor. Fabricate steel moves, the finish follows, and Driver says why.

Handover: Finish on or before the contract date. A ceiling, so the finish does not move. Instead: negative float. The chain is five days late against the target, and Late finds it.

Under Project, Must finish by is one target for the whole schedule. Run past it, float goes negative. As late as possible slides Order fit-out to its late date: handy for orders and payments, little else.

Mandatory start overrides logic: the steel goes up before the footings are poured. The schedule lies. First, draw the logic. A delivery is a milestone and a link, not a constraint.

Second, few constraints, and targets rather than mandates. One ceiling on the handover is enough. A date can carry a time: type it after the date. Schedule options sets how it displays.

That was constraints. Next in the Guide: the four scenarios, starting with a Microsoft Project file in Simple mode.

Taken from the video’s English captions.