- We find a better way to do work that costs less money, takes less time or increases scope without affecting any of the other constraints. Great! Just do it and report the good results in the next status report.
- Tasks are not affected in duration, cost or scope, we simply determined a different way to do it or discovered a few more sub-tasks required. Your Gantt chart should be at the task, not the sub-task level so don't add anything here. The task owner can adjust their sub-task list which may be in their head or written down.
- Tasks are negatively affected by the change but the critical path and the project budget are not affected. You need to report this but add that the overall project constraints are not affected. As a Project Manager you have the authority to take steps to manage these changes within the constraints given you by the Project Sponsor. They gave you enough time and money to complete the given scope. So manage this within the team and report to the Project Steering Committee. Note how this is different to the next situation. Do make changes to your Gantt chart.
- Changes cause the Project Scope, Quality, Schedule or Cost to change negatively. This is where you have exceeded your authority. Hopefully you have a Change Management Process in place that you can use to deal with changes of this type. You need to get the team together and work the change through the change control system. Determine the options the management team can take and the effect each option has on the Cost, Schedule, Quality, Risk and Scope of the project. Determine the team's recommendation for change. Recommend that to the Steering Committee. The Steering Committee may or may not agree with your recommendation. That is their right. Your job is to stick to the authority given you. Change your Gantt chart to reflect the change the Steering Committee came up with. Click on this link to see what happened to the hero of my book when he forgot this basic point.