finish to finish [FF] relationship (dependency) examples in project management

Finish To Finish is a logical relationship (or dependency) in which a successor activity cannot finish until its predecessor activity has finished.

Finish to Finish (FF) is one of the four activity relationships of project management. These are used while preparing project schedule. The other three relationships are:

  1. Finish to Start (FS) relationship
  2. Start to Start (SS) relationship
  3. Start to Finish (SF) relationship

Let us understand FF relationship in greater depth by using examples, Gantt Chart, Network Diagram, and Mathematical formulas.

Finish to Finish Relationship (Dependency) in Project Management

As per the PMBOK Guide “Finish to Finish is a Logical Relationship in which a Successor Activity cannot finish until a Predecessor Activity has finished”.

However a better definition is, “Finish to Finish is a Logical Relationship in which finishing event of a Successor Activity is dependent on the finishing event of a Predecessor Activity”.

To understand the above definition, let us look at the events of an activity and not the whole activity. The two distinct events of any activity are:

  1. Start Event (S)
  2. Finish Event (F)

In FF relationship, the Finish event of the Second Activity is dependent on the Finish event of First Activity. The Second Activity is called the Successor and the First Activity is called the Predecessor.

You can also look at Max Wideman’s Glossary for a complete set of PDM definitions.

Note: An activity or task relationship is loosely termed as project management dependency. However, these two terms are different. A relationship between two activities can be established only if one activity is dependent on the other. Just like relationships, there are four type of project management dependencies.

Finish To Finish Examples

Let us consider two activities X and Y. X and Y are predecessor and successor activities respectively. The following examples show FF relationship between X and Y:

  • X – Write Code for S/W Module Alpha, Y – Unit Test S/W Module Alpha
  • X – Lay Electrical Wires, Y – Inspect Electrical Wires

Representation of Finish To Finish

Gantt Chart

An FF relationship can be visually depicted using using Time Scaled Bar Charts, which are popularly known as Gantt Charts.

Let us consider two activities A and B.

  • Duration of A is 3 days.
  • Duration of B is 1 day.
  • B has a FF relationship with A

The Gantt Chart below shows FF relationship between A and B.

As per the above diagram B’s Finish is dependent on A’s Finish, which means that B can Finish(F) as soon as A finishes(F).

In the above example, A and B together are scheduled to be completed in 3 days.

Project Network Diagram

An FF relationship can also be drawn by using Precedence Diagramming Method (PDM), which can be visually depicted by Project Management Network Diagrams.

Let us again consider the above two activities A and B. The Network Diagram below shows FF relationship between A and B.

finish to finish

Mathematical Formulas

Again considering the above two activities A and B, we can mathematically represent the relationship between A and B as:

B(F) = A(F)

The formula will remain same whether we use 0 method or 1 method

Finish to Finish with Lead and Lag

FF relationships can be further modified by introducing project management Leads and Lags modifiers.

The following Lead and Lag examples use 0 method representation.

Two activities J and K having FF relationship with 1 day of Lead:

K(F) = J(F) – 1 day

Two activities L and M having FF relationship with 2 days of Lag:

M(F) = L(F) + 2 days

Over to You

PDM Relationships can be represented by using mathematical equations. However, not all mathematical relationships represent the natural logic. While making a project schedule, you should ensure that all dependencies follow the natural logic and are true in the real world.

Do you think FF relationship is useful in real projects? Have you ever used it in you project(s)? Or have you seen it being used?

I would love to hear from you.

PMP Exam Formulas

I have also compiled a PMP Formulas Cheat Sheet. It contains 45 formulas and 57 abbrviations. It will help you in your exam prep. It is the best and most comprehensive cheat sheet based on the PMBOK Guide 6th edition. You can download it free of cost for your studies.

If you are looking beyond a cheat sheet, then I would suggest you to buy detailed PMP Exam Formula Study Guide by Cornelius Fichtner. It contains detailed explanations of all the formulas along with examples and 105 practice questions.

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  1. the guard example is not a good one for this relationship. The start of the successor is dependent on the finish of a predecessor not vice versa. The morning guard can’t start until the night guard has finished. The morning can finish if the night guard has started does not make sense

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