Large development projects require experienced managers. Percentage wise large projects fail much more than smaller counterparts. Large projects have complexity in every aspect which is difficult for many project managers to handle. Compelxity can be due to either technology, Project Size, Project domain, Project team size, location(s) of implementation etc. 

Why are Large Projects different.

• Scope is not granularly known like small projects.
• Strict contract terms ( Fixed price or SLA Penalties) 
• Multiple Vendors or Departments participate to deliver the scope, requires superior Project integration skills. 
• Unexpected Risks all along and inadequate risk responses. 
• Large projects need an experienced Project manager.
• Large projects need domain expert who can guide the team from functional and technical perspective.
• Large projects have long time line, hence there are people management related issues which are difficult to predict and resolve. 
• Large projects are usually part of some business transformation program within the organization. Hence one has to look at a large picture and not only at success of current project. 
• When there are changes, PM must ask “What customer wants” ., rather than be a roadblock in implementating the changes.
• In large projects issues get magified. For a PM who has only handled small projects , they may not be able to guage the intensity of the issues. 

What do we call Large ?

Large projects are comparative. If you are a PM who has handle 1 million USD project. A 5 million project would be considered as large  and you need to be willing to see the project in new light. If you handle a 5 million project the same way as 1 million project you are basically headed for disaster.  So lets say when size increases 3 to 5 times. The project would classify as a large project and PM will need to develop special skills to handle the project.

Top Issue or Risk in Large projects

As per the study done for various large projects in Information technology industry, the number 1 risk / issue is High Level Scope. 

Problem of High level Scope.

Problem of Scope change 

• Sponsor starts the project optimistically with low investment and neglects basic project management aspects. Sufficient investment is made eventually, but is too late. Bad decisions made at start are not retreated.
• Senior management fails to put appropriate governance, gives low attention at start, which is disastrous.
• Team skills are compromised at start, We put Junior resources to save cost.
• Instead of incremental roll-out , Big-bang rollouts are planned.

Client and Vendor are learning about the project. Client is learning about technology and vendor is learning about the project domain. Due to this the Project scope is bound to change. Any clarification from vendor can result in scope increase . Likewise cleint may not have been tech savvy enough and once they learn about the software capabilities they want to add more requirements to the scope. 

Solution 

• Client and vendor must understand that product scope is different from project scope. Estimation is done on project scope and both parties must be open to changes to scope, schedule and cost. 
• Give early prototype to the client so they can suggest changes early. Changes at later stage can mean huge rework cost. 
• Project manager must be strong enough to say NO to certain requirements. PM must focus on completing the project in given time and cost. Additional requirements must be pushed to later phase of the project. Project Manager's negotiation and influencing skills play a big role here.