While the project is ongoing and we cannot look back upon history to guide us through an impact analysis we must estimate the impact to future project events. Many years ago the Corps of Engineers realized this and durived a process called Time-Impact Analysis. This analysis starts with the datadate of the current schedule (just prior to the impact) as the baseline and impacts the events based on best estimates of the outcome from the known impact.

If your current schedule is not correct or your short period look ahead has not been reviewed for latest knowledge then the Time-Impact Analysis is less that the accuracy you would normally desire in an estimate.

SEEK THE HELP OF A PROFESSIONAL