Finish to Finish/Start to Start Dependencies with Lag.

This tip explains Lag with Dependencies other than Finish to Start, like Finish to Finish and Start to Start, in Microsoft Project 2013.

First we create a simple project:

Nenad Trajkovski FF-SS figure 1

As you can see in the Predecessors field, Tasks 1 and 2 have a Finish To Finish (FF) relationship, and Tasks 3 and 4 have Start To Start (SS) Dependencies. Now, suppose that Task 2 and Task 4 have two days of lag:

Nenad Trajkovski FF-SS figure 2

You get:

Nenad Trajkovski FF-SS figure 3

Task 2 will have a finish date of August 4, 2015 and will start two days later, so its start date is postponed!

When we repeat this for Task 4 we get:

Nenad Trajkovski FF-SS figure 4

The same result! The point to remember is that, yes, you can have Lag (and Lead) in tasks with dependencies other than Finish to Start, but be aware of consequences!

Written by Nenad Trajkovski
Nenad Trajkovski, born in Zagreb in 1963, is an accomplished professional with a background in Electrical Engineering. With expertise in enterprise systems (ERP) development and implementation, he has served diverse sectors including banking, casinos, automotive, wholesale, and oil industries. Nenad excels in business process management, IT, and financial accounting. Currently, Nenad is a seasoned consultant and Project Manager, specializing in business systems implementation. He is also a respected trainer for Project Management and Risk Management at the Microsoft Innovation Center in Varaždin. Nenad's speaking engagements have earned him recognition, including being named the best speaker at WinDays08 and ranking among the top speakers at various Microsoft conferences. Nenad holds multiple certifications including Certified Accountant, PMP, PMI – RMP, MCP, MCTS – Microsoft Project 2010, and MCT.
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  1. I actually prefer to put lags on SS or FF type of dependencies instead of using a FS with a Lead. However. You need to make sure you have a dependency that controls both ends of your task or the Critical Path may not be correct. Especially if you only use a SS dependency and don’t control the end of the task.
    An issue I have found with using SS or FF dependencies, the Task Inspector doesn’t work the way it should. Have you also found this to be true?

    great article. Thanks,

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