Start to Finish Relationship – Definition, Examples & Explanation

Start to Finish Relationship in Project Management

start to finish

In this article, I have defined and explained Start To Finish Logical Relationship with the help of Project Network Diagrams, Gantt Charts & Examples. Start to Finish (SF) is one of the four relationships described in Precedence Diagramming Method (PDM). The other three are:

  1. Finish to Start (FS)
  2. Start to Start (SS)
  3. Finish to Finish (FF)

These are used to represent and analyze project schedule. This concept originated with PDM. However, by using modern scheduling tools like MS Project and Primavera, you can pictorially represent them on Gantt Charts as well. These relationships are sometimes referred to as project dependencies but former is a better term.

 

The Definition

Start To Finish is a Logical Relationship in which a Successor Activity cannot finish until a Predecessor Activity has started.

PMBOK Guide 5th Edition

In simple words we can say that, the Finish of a Successor Activity is Dependent on Start of the Predecessor Activity.

The most common and natural relationship is Finish to Start (FS). Some authors (incorrectly) claim that FS and SF are essentially same. However, it is not true. Even though it is mathematically possible to transform SF to FS to achieve the same result, one should not modify and tamper with natural logic. In real world, SF is very rarely used. You can read FS vs. SF for more details.

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

 

Representations

Project Network Diagram Representation

Let us consider two activities A and B.

  • Duration of A – 3 days
  • Duration of B – 1 day
  • B has a SF relationship with A
  • B’s Finish is dependent on A’s Start – B can Finish (F) as soon as A Starts (S).

 
start to finish
 
In the above example, the Project Team would need a total of 4 days to complete these activities.

 

Gantt Chart Representation

start to finish
 

Mathematical Representation And Formulas

If you are using 0 method

B(F) = A(S)

Or, if you are using 1 method

B(F) = A(S) – 1

 

Start To Finish Examples

  • A – Duty of Evening Guard (E), B – Duty of Morning Guard (M). M cannot Finish her/his duty till E Starts. M cannot abandon the post.
  • A – Start using New Software System (N), B – Phase out Old Software System (O). It is assumed that N & O cannot be used in parallel.

 

Over To You

SF is not a very difficult concept to understand. But it is somewhat confusing because of the FS. After reading this article, do you still have a question(s)?

Do you think it is useful in real projects? Or, have you ever used it in you project(s)?

Please leave a comment.

 

PMP Exam Formulas

I have also compiled a PMP Formulas Cheat Sheet. It will help you in your exam prep. You can read more about it and directly download it free by joining PMP prep linkedin group. It is the best and most comprehensive cheat sheet based on the PMBOK Guide 5th Edition.

 

 

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.

 

Related Articles

What are Project Dependencies

4 Types of Project Dependencies

Lead vs Lag

FAQs on Lead and Lag

o and 1 Method To Solve Network Diagrams

Praveen Malik, PMP is a certified Project Management Professional (PMP®) with a rich 20+ years of experience. He is a leading Project Management Instructor and Consultant. He regularly conducts Project Management workshops in India & abroad.

4 thoughts on “Start to Finish Relationship – Definition, Examples & Explanation

  1. Good article, but one instance that you hadn’t considered in your explanation which is more often used in my arena: When you develop a project schedule with a Finish Date in mind (customer defined requirement for Launch Date). In “working backwards from the end date” planning, the SF dependency is used quite a bit.

    If you have a better suggestion than SF dependencies in this scenario, I’d like to hear about it.

    • Hi Bob,

      The relationships do not change whether you “Schedule From Start Date” or “Schedule From Finish Date”. I suspect most of your relationships would be FS. Plese note that these are Logical relationships and not mathematical relationships.

      I think you may want to read more about constraints like “As soon as possible” and “As late as possible” if you using a tool like MS Project.

      You should also read more about the network diagrams. You can start with:
      Need for a SF relationship – https://www.pmbypm.com/need-start-to-finish-relationship/
      Project Network Dagram explaned – https://www.pmbypm.com/project-network-diagram/

      BR
      Praveen.

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