This post found on pm4girls features an extract from Elizabeth Harrin's contribution to the book Project Pain Reliever by Dave Garrett. The extract focuses on a common problem in project planning: doing it all yourself. The problem, as Harrin explains, is that other people involved in the project will feel like you short changed the work they need to perform – and will create their own timetables to counteract your “closed door” project planning:
You have a great project plan, with lots of detail. It's properly documented and you have built a schedule that gets everything done by the date the Sponsor wants. However, now the team have started working on the project, it is clear that they are sticking to their own timescales and not paying any attention to your masterpiece. In fact, at the last team meeting they went as far as to tell you that your schedule is completely unrealistic. OK, you missed out the testing phase, but surely that won't take very long? Everyone is doing what they can, and the team is working long hours to get tasks completed on time, but they are starting to resent the fact that you signed them up to this. You don't know how long you can keep the project going when it's obvious that the team doesn't believe in the plan or the schedule. Harrin goes on to explain what warning signs you should be looking for (including concerns about the timescales, a lack of timely task completions, and long hours worked in office), and how to avoid schedule disbelief through not “planning in a vacuum”. By involving team members in your planning process you assure their buy in as well as their expertise!