I liked this WiggleChart and the annotation “resources reallocated.”
This before-the-fact warning system indicated to this team that they had a negative trend. Resources had been gradually sucked off of this project and placed on other projects that where determined to be higher priority. The result was the slip that started when resources left the project (see red arrow). It took about 6 weeks of trend information to alert the team that the loss of resources were impacting the schedule.
Green means you have a chance of hitting your target (i.e. a pull-in of one day per week is needed to hit the target date), yellow means 1-2 days a week need to be pulled-in each week, red indicates that more than two days are needed. There is still time to pull-back the lost time before the target, which is way to the right. What would have happened had the early warning system not been in place?