Activity Relations

[Vishwadeep Khatri]

Q 515. In Project Management, there are 4 types of relationships possible between 2 activities - Finish to Start, Finish to Finish, Start to Finish, Start to Start. Highlight the differences in these 4 relationships. Provide clear examples to support your answer.

 

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[Gulshan Kumar]

Projects are a set of activities or tasks that must be completed in some pre-defined sequence by individuals or groups of individuals, within a certain timeframe, and using a specific set of resources or domain knowledge. There are a set of relationships that can exist between the start and end points of these activities/processes in their execution.

There are four possible activity relationships, which are defined in the Project Management Institute's “Project Management Body of Knowledge (PMBOK).”

These relationships are Finish-to-Start, Start-to-Start, Finish-to-Finish and Start-to-Finish.

FINISH –to- START

The Finish-to-Start relationship means that one activity (predecessor) must be fully complete before any following (successor) activities may begin. It happens to be the most common activity relationship in project management.

Example: -  Newspaper Writing. The writing and editing processes share a finish-to-start relationship because the editor can't start the editing process until the writer has completed their work on an initial draft formation.

Example: -  Film Making .
START-to-START
The next relationship is Start-to-Start. In this phase, an activity cannot start until and unless another activity also starts. Example: -  Painting an apartment/home. Each room needs a coating of primer and painting. The priming and painting share a start-to-start dependency because the homeowner must apply the primer coat before they can apply paint . Although paint can only begin after the primer, as the homeowner awaits one room's primer to dry, they can apply primer to the rest of the rooms they wish to paint.
FINISH-TO-FINISH
This phase of relationship exists where two or more activities can only be considered completed if and when both are completed. Example:- Computer Manufacturing. Employees in each department are involved in creating memory chips and assembling motherboards. The creation of memory chips and assembling motherboards share a Finish to Finish dependency.
START-to-FINISH
And finally, we come to the Start-to-Finish relationship. It is rarely found in real-life projects. In start-to-finish relationships, as soon as the predecessor activity starts, the successor activity will get finished. Company manufactures products and sells them directly to consumers for consumption/usage.  For delivering a product, the company requires both warehouse and shipping operations in tandem. The warehouse and shipping departments share a Start–to-Finish relationship for each product they send out for delivery.
Benefits of Activity Relationship in Project Management
 

Activity relationship in Project Management helps in identification of :-

·        Project deliverables that meets stakeholder expectations and business objectives.

·        Timely and expedited delivery.

·        Project deliverables with minimum or zero defects.

·        Enhanced cost control.

·        Increased quality of product delivery.

·        Reduced rework .

·        Reduced customer complaints and grievances.

·        Integration of Supply Chain & Logistics.

·        Improved productivity.

·        Increased team morale and satisfaction, motivation.

·        Strong service delivery.

·        Improved decision making.

·        Continuous improvement of process.

 

[Rahul.Arora2]

At the simplest level, projects are about a set of activities or tasks that must be completed in some defined sequence. There are a defined set of relationships that exist between the start & end points of the activities. These are Finish to Start, Start to Start, Finish to Finish & Start to Finish. Let us explore these four kinds of relationships along with relevant examples.

 

Finish to Start :

 

Finish to Start is a logical relationship in which a Successor Activity cannot start until a Predecessor Activity is finished i.e. the starting event of a Successor Activity is dependent on the finishing event of a Predecessor Activity. Here the predecessor activity must be fully complete before any successor activity has begun. It is the most common relationship amongst all four relationships.

 

The Finish to Start relationship can be represented on the Gantt Chart & Project Network Diagram as shown below with A as the predecessor activity taking 3 days & B as the successor activity taking 1 day:-

 

 

Let us take the example of Setting up a router to showcase the Finish to Start relationship. In this case, one must finish deciding where to install the router before one can start the next step i.e. plugging in the router. Another scenario can be configuring a wireless router gateway, before starting to connect it to the router.

 

Start to Start :

 

Finish to Start is a logical relationship in which a Successor Activity cannot start until its Predecessor Activity has started i.e. the starting event of the Successor Activity is dependent on the starting event of the Predecessor Activity. 

 

The Start to Start relationship can be represented on the Gantt Chart & Project Network Diagram with Activity A having duration 3 days, Activity B having duration of 1 day as shown below:-

 

 

Let us again take the same example of router set up with some tweaks. Let’s say that we have multiple, rack-mounted routers & we need to slot them in & then connect them to the internet. Here slotting in the routers is the predecessor activity & connecting them to the internet is a successor activity. Here as soon as we start to slot the routers into the rack, we can also start to make the internet connections. Thus we don’t need to start to make the internet connections immediately, but the first one must have begun ti plug the routers into their rack slot.

 

Finish to Finish :

 

Finish to Finish is a logical relationship in which a Successor Activity cannot finish until its Predecessor Activity has finished i.e. the finishing event of a Successor Activity is dependent on the finishing event of a Predecessor Activity. This relationship exists where two or more activities can only be considered completed when both are completed.

 

The Finish to Finish relationship can be represented on the Gantt Chart & Project Network Diagram with Activity A having duration 3 days, Activity B having duration of 1 day as shown below:-

 

 

Let us again take the router example, now we are bringing a new server online. You need to load & configure the server operating system & you must also connect the sever to the router. Here configuration of the server operating system cannot be considered complete until the server is connected through the router to the network. Here in this case both activities can begin independently, however to ensure a fully functioning server on the network, both activities need to be completed.

 

Start to Finish :

 

Start to Finish is a logical relationship in which a successor activity cannot finish until its predecessor activity has started i.e. in which the finishing event of the successor activity is dependent on the starting event of a predecessor activity. This kind of relationship is rarely found in real life projects, as soon as the predecessor activity starts, the successor activity will finish.

 

The Start to Finish relationship can be represented on the Gantt Chart & Project Network Diagram with Activity A having duration 3 days, Activity B having duration of 1 day as shown below:-

 

 

The best example to explain this kind of relationship is let’s say, we are installing a new router to replace the old one. One can’t finish disconnecting the old router until the new router is up & running i.e. starting the go-live activity for the new router is the trigger to finish the disconnect activity for the old one.

[M V Ramana]

Projects are a set of activities or tasks and completed in a defined sequence by individuals or groups of individuals, within certain timeframes, and using a specific set of resources.

The start and end points of these activities there are a defined set of relationships that can exist

Activities have two types of relationships i.e., a workflow relationship or a data relationship. Data relationships are further divided into two types

1.                Insert data or reference data and are these are inter dependencies

There are four types of activity relation which are explained below

1. Finish-to-Start

The Finish-to-Start relationship means that one activity before any following successor activities the predecessor must be fully complete may begin.

In project management, Finish-to-Start is the most common activity relationship.

Example: finishing configuration of a wireless router gateway by a certified network admin, before starting to connect it to the router.

 

2. Start-to-Start

The next relationship is Start-to-Start.

Until and unless another activity starts this activity cannot start.

Example: multiple rack-mounted routers slotted them in and then connect them to the internet. The routers slotting in is the predecessor activity and routers connected to the internet is the successor.

 

3.      Finish-to-Finish

In this relationship two or more activities exists and can only be considered as the activity completed when both are completed.

Example: We need to load and configure the server operating system and also must connect the server to the router. Which are the examples of finish-to-finish activities.

 

4. Start-to-Finish

Start-to-Finish relationship is the last. In real-life projects this relationship is rarely found. In start-to-finish relationships, the successor activity will finish as soon as the predecessor activity starts.

Example: like in a cut-over to a new system. The best example would be if migrating to a new system.

 

[Dimple Tiwari]

4 Types of logical Relationships or Dependencies in a Project Schedule

In simple words –
After identification of conditioning, we dissect them if any connections live between those. However, it's better to show them to maintain the design schedule more, If connections live.
The relationship exists between the two conditioning. Let’s take two conditioning for understanding the conception and name the exertion A and B.

Then, exertion A is a predecessor, and exertion B is the successor activity. However, it impacts the successor conditioning, If commodity happens to the predecessor exertion. In this way, successor exertion B is a dependent exertion on the predecessor exertion A. So, you can see then – A is an independent exertion. exertion A logically comes ahead exertion B in the schedule. The connections between A and B exertion are either of four types
•    Finish- to- Start (FS)
•    Finish- to- Finish ( FF)
•    Start- to- Start ( SS)
•    Start- to- Finish ( SF)
We define these four relations by two exemptions (XX) using F or S.
We link the predecessor (exertion A) with the first character. It defines the state of processor exertion. And, in the same way, we link successor ( exertion with the alternate character. The character defines the rule which we've to apply on the successor exertion. 

 

Let’s discuss these four relationships one by one:

Finish-to-start (FS)

“A logical connection in which a successor venture cannot start until a predecessor activity has finished.”
 

Still, Finish to launch is the most generally used logical relationship, If you have a question – which is the most generally used logical relationship? Yes.

You can see, this relation constraint doesn't impact the independent exertion. It only affects the dependent, so in our case, it's exertion B.

Then the coming question is – what does FS mean in design operation?

 

From this FS relationship, F shows the finish state of exertion A, and at this state, exertion B can be started. The alternate character ‘ S ’ is the rule on a successor to make it dependent on the Finish state of the successor exertion.

Let’s take an illustration –

You can not start development until you finish the design. Then, development is the dependent exertion on the design exertion. Design is the precursor exertion, and its finish state can only start the development exertion.

 Start-to-start (SS)
“A logical relationship in which a successor activity cannot start until a predecessor activity has started”
So if exertion B is bound to this relation, this means it can not start till the precursor( independent) exertion A is started. The precursor exertion B launch is dependent on the launch state of successor exertion A. The launch of exertion A drives the launch of exertion.

 

Let’s take an illustration –
The exertion of marketing folder medication can not start until stoner attestation has begun. In this way, after the inception of exertion A, both A and B can go in parallel.
If you're curious to know in what could be the practical cases to make exertion B dependent on the launch state of exertion A –

Finish-to-finish (FF)
“A logical connection in which a successor activity cannot finish until a predecessor activity has started.”
 

So if exertion B is bound with this relation it means it can not finish till the precursor( independent) exertion A is finished. So, B needs to finish its deliverable and keep working with A till the time A isn't done.

Like, the broadcast of a football match can not finish until the match is finished. So the match isn't depended in broadcast, but the broadcast is. If the match takes longer than the originally estimated time broadcast will also continue till that time.

It could be possible that the broadcast is continued indeed after the match is finished. The broadcast could be continued to bandy highlights and other effects. It means it'll end after successor conditioning but inescapably incontinently.

 

Start-to-finish (SF)

So if exertion B is bound to this relation in which it can not finish till the independent exertion A starts. It looks confusing because in typical cases, precursor exertion gets performed before the successor exertion. But, in this case, the successor is passing first. But indeed if the successor is passing first, the precursor isn't at each confined by successor exertion. It's independent. But the successors( exertion can not finish till the precursor starts( exertion A starts)
A logical connection in which a successor activity cannot finish until a predecessor activity
has started.

It's pivotal to understand the introductory generalities underpinning these four logical connections or dependences between design conditioning. So, make sure you work on them right from the launch and bandy all the tasks and record them consequently.
 

[Godwin Thomas]

When a logical relationship exists between two activities needed as part of a project, then a Precedence Diagram Method (PDM) is used to represent the relationship between the two activities. This technique is widely adopted for scheduling activities in project management. 

 

In PDM, there are four different types of logical relationships that are possible between two activities. They are a) Finish to Start b) Finish to Finish c) Start to Start d) Start to Finish. To understand the four logical relationships better, we need to first understand what a predecessor or a successor activity means. In a schedule, predecessor activity is an activity that comes before a dependent activity and successor activity is a dependent activity that comes after another activity. 

 

a) Finish to Start: In this relationship, the successor activity cannot start unless the predecessor activity is finished. This is the most widely used relationship visible commonly across many workflows / processes. For example, you cannot proceed with payment for your ecart unless you have added all the items to your cart when using an ecommerce platform. In this example, payment initiation, which is the successor activity cannot start unless the predecessor activity, which is, adding items to cart is completed. Similarly, you cannot upload the ITR form (successor) unless you have filled-in all the mandatory pre-requisite fields (predecessor).

 

b) Finish to Finish: In this relationship, a successor activity cannot finish unless the predecessor activity has finished. For example, the security guard cannot finish his activity of closing the shop (successor) unless all the customers have finished shopping and left the shop (predecessor). If a document has to be peer reviewed by an approver before it can be published, then the activity of document closure by publishing (successor) cannot finish unless the approver has finished his/her review and approvals (predecessor)

 

c) Start to Start: In this relationship, the successor activity cannot start unless the predecessor activity has started. In other words, the start of successor activity is dependent on the start of the predecessor activity. For example, you cannot start the activity to load the cake into an oven (successor) unless the oven preheat activity has started (predecessor). For a reliability test of a spring, you cannot start the activity to measure the spring stress (successor) unless the spring loading activity (predecessor) has started.

 

d) Start to Finish: In this relationship, the successor cannot finish unless the predecessor has started. For example, in case of product delivery, a project/program management team cannot finish or cease to support (successor) unless the operations teams starts the takeover (predecessor).  

 

 

 

[Anuj Bhatnagar]

Four types of activity relationships in Project Management

There are 4 types of relationships in Project Management between any 2 activities, namely Finish to Start (FS), Finish to Finish (FF), Start to Finish (SF), Start to Start (SS).

Before getting into the details, first let us consider 2 activities A and B. Activity A precedes activity B, hence A is an independent activity while B depends on A. Also, A can be referred as predecessor activity while B can be referred as successor activity. The direction of the arrow depicts the direction (dependency) in the precedence diagram.

The types of relationships that can exist between these two activities, A & B are based on the dependencies of start and finish times of these 2 activities. Hence, 4 combinations are possible based on start & finish times for A and start & finish times for B.

Now let us take a closer look at these 4 relationships.

Finish to Start (FS) – This is the most common type of relationship in project management. Here, activity B i.e., the dependent or successor activity cannot be started until the independent or predecessor activity A is completed.

 

A typical waterfall model approach for software development is a classic example. Design cannot be started until requirements are complete, development cannot be started until design is done, testing cannot be started till development is complete and so on.

Finish to Finish (FF) – In this relationship, activity B i.e., the dependent or successor activity cannot be finished until the independent or predecessor activity A is also completed. Note there is no dependency on starting activity B on completion of activity A though. At some point of time both the activities can be in progress, but A must finish first only then B can be completed.

 

Live telecast of a cricket match is one such example. The live telecast is dependent on the match itself and can end only after the match has ended. However, the telecast can start irrespective of the match’s start and may continue even after the match ends, but it ends only after the match ends.

Start to Finish (SF) – Here, activity B i.e., the dependent or successor activity cannot be finished until the independent or predecessor activity A is started. However, there is no dependency of finishing activity B on completion of activity A.

A typical example from software world is migration to a new system and decommissioning of old system. Availability of the new system up & and running is a pre-requisite for the old system to be decommissioned.
Start to Start (SS) – In this relationship, activity B i.e., the dependent or successor activity cannot be started until the independent or predecessor activity A is also started. Activity B has no relation with finishing of activity A though.

Referring to the field of software again, in general all the review activities fall under this category. Incremental review & validation activities are dependent on the corresponding tasks like writing code is needed to start reviewing the code, user manual or documentation review has a pre-requisite to start creating the documentation itself.  

 

[Mayank Gupta]

While all published answers are correct and with relevant examples, Gulshan's answer also highlights the benefits of identifying the relations in project management. Hence his answer has been selected as the winning answer.