Schedule Maintenance and Control
Maintaining a live schedule
Schedule maintenance keeps the model a truthful forecast, and schedule control uses it to detect and respond to deviation. Concepts: baseline schedule versus current schedule; data date; update cycle; actual start and finish dates; remaining duration; physical percent complete versus duration percent complete; out-of-sequence progress; change control and re-baselining criteria; look-ahead schedules; and variance reporting against the baseline.
Traps: moving the baseline to hide variance; recording progress by elapsed duration instead of earned physical progress; leaving logic that no longer reflects how work is executing; updating without advancing the data date; and accepting out-of-sequence updates that create artificial float or false critical paths. Another frequent trap is confusing a revised schedule, where logic and remaining work are updated, with a re-baseline, which requires approved scope or time change.
Worked example: a 10-day activity is 8 days into execution but only 40 percent physically complete. Remaining duration is not 2 days; it is (1 minus 0.40) times 10 = 6 days, pushing the forecast finish 4 days beyond plan. Reporting the duration-based figure understates the slip.
Rule of thumb: every update should answer four questions - where are we (data date), what is done (actuals), what remains (remaining duration), and does the logic still describe the work? Check the change log before accepting any date movement not explained by progress.