7.4.1.3 Determination of activities sequence

and dependencies

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Once the Activities have been identified and broken down to smaller components, they must be related to each other to determine the activity sequencing (order in which the activities should be undertaken) and dependencies (which activity must be completed before the start up of another activity).

This can best be described with an example. Implementing training in the Public Procurement Best Practice Guide to 100 main purchasers from the Cypriot Contracting Authorities has as prerequisites the following: Completion of the compilation of the Best Practice Guide, Formulation of the Training strategy, Development of the Training Programme and Preparation of the training material. The sequence dictates that the preparation of training programme and training material comes before the training delivery; while dependencies include the fact that training cannot start until the Contracting Authority approves the training material. Dependencies may also occur between activities that will be undertaken by the same person (i.e. a trainer who is assigned to provide training both to future trainers and to main purchasers may not be able to complete both tasks at the same time).

Dependencies can be distinguished in the following types:

Mandatory dependencies: Mandatory are those dependencies that are inherent in the nature of the work (e.g. on a construction project, the walls can not be built and plastered until after the foundation has been laid)
Discretionary dependencies: Discretionary dependencies are those defined by the Project Management Team. Normally the Project Management Team has a good knowledge of the thematic area in which the project refers and besides is aware of any unusual aspect of the project that oblige the application of a certain implementation sequence
External dependencies: External dependencies are those derived by non-project activities (e.g. software testing depends on the delivery of the hardware by an external supplier).

 

Any schematic display of the logical relationships of project activities is called Project Network Diagram. There is more than one technique to construct a Project Network Diagram (Precedence Diagramming Method, Arrow Diagramming Method and Conditional Diagramming Methods). Besides, it may be produced manually or automatically by using specialised computer software. In the following paragraph the Precedence Diagramming Method is presented, since is the one used by most of the project management software packages (e.g MS Project, Primavera Planner).

According to this method, the Activities are presented as boxes and their dependencies as arrows. There are four types of dependencies but only one is the most commonly used, the Finish to Start. More specifically, the types of dependencies are:

Finish to Start (FS): In this case the work of the successor can not start until when the work of the predecessor has finished
Finish to Finish (FF): In this case the completion of the work of the successor depends on the completion of the work of the predecessor
Start to Start (SS): In this case the initiation of the work of the successor depends on the initiation of the work of the predecessor
Start to Finish (SF): In this case (it is rarely used) the completion of the work of the successor depends on the initiation of the predecessor.

A typical diagram drawn using the Precedence Diagramming Method is presented in the following scheme:

 

Figure 7-7: Project Network Diagram using the Precedence Diagramming Method.

 

It should be noted that nowadays such types of diagrams are prepared quite automatically by using specialized software. All types of dependencies between the activities are being “declared” when producing the time schedule and they are automatically presented as connecting arrows on the Gantt chart. In this perspective, the Project Network Diagram itself is not something compulsory, but the activities’ sequence and dependencies must be identified, since they are necessary for the activities scheduling.

 

Example 7-5: Activities sequence and dependencies for the Project “Improving the implementing capacity of the Cypriot Authorities”

Project: “Improving the implementing capacity of the Cypriot Authorities”.

Following the identification of the Project Activities (refer to 7.4.1.2) their sequence and dependencies must also be identified.

The Development of the Web based solution for the Public Procurement Best Practice Guide should not start until when the compilation of all the Chapters of the Guide has been completed
The preparation of Training material should not start until when the compilation of all the Chapters of the Guide has been completed
The training delivery should not start until when the compilation of all the Chapters of the Guide has been completed and until when the training material has been prepared.
The training of main purchasers and other staff involved in public procurement should not start until when the future trainers have been trained.

In case that you would like to present the above mentioned dependencies in a diagram form, you should conclude to a diagram like this:

 

 

 

 

 

 

 

 

 


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