When a project begins, there are expectations of it going according to plan.  Unfortunately, projects often take on a life of their own.  There are many points where it is best to stop, take a deep breath, determine where you are and where you want to be, and how best to get there.

A project plan, at best, is an estimate and a road map that you desire to follow.  If your mindset is that you cannot veer from it, then you'll likely be disappointed.  In the real world, this map does not take key factors into account that can and will affect your project.  Also keep in mind that scope changes, unexpected organizational changes and testing can influence your plan.

What are some of the key factors you ask?  Let's look at a few of them.

1)      Resources:  When dealing with resources, there are foreseeable and unforeseeable things that can happen.  A foreseeable thing is that your resource has a full time job and now you want them to focus on a project that may require 25% to 80% of their attention, depending on the phase of the project.  Realistically, something will have to give one way or another.  An unforeseeable item is if you have a key resource that you are counting on and they hand in their resignation to you halfway through the project.  In both these cases, you end up with resource constraints that could negatively impact your project plan.  Your budget should always reflect a reserve to add additional resources if needed.

2)      Data:  You find that your data has issues that you knew nothing about because somebody was manually manipulating it to make it work.  Data issues play a primary role in project success or failure, and you can run through your project budget very quickly dealing with them.  Unfortunately, most are not identified until the implementation is under way.  Anticipate their occurrence and work through your data issues as they are identified.

3)      Testing:  The testing phase determines if the system is functioning, and if it functions to the user's requirements.  Many times, the testing process will take longer than anticipated.  It is reasonable to expect user acceptance testing to take four to six weeks, but I have seen it run much longer.  Setting realistic expectations of what is involved in the testing process can aid in success.  Expecting actuals to match 100% to expected results is unrealistic.  Why you ask?  Because there is always some exception that must be processed that was not taken into consideration for your implementation.  It is not realistic to expect all exceptions to be programmable or implemented in the new system.  Be aware of resource constraints and ensure resources can be available to focus on the project or add additional resources to assist with the implementation.

Your project plan is, at best, an estimate of your road map.  Keep in mind that implementations are not set in stone, and as you proceed through your plan, you may find you need to make adjustments.  Don't be afraid to stop, take a breath and revisit what you are doing, where you are, and adjust to get where you want to be.  I believe it better to be proactive and determine that it's necessary to change the plan, than to proceed and have to explain later why it was not achievable.