I am new to current company. After reviewed the old project history, I found all projects have L1 project start date, L1 project end date, L2 project start date ... etc
After talk with a senior PM, he said L1 is referring to "planned date" before charter submit. L2 refer to the date in charter. L3 refer to the actual date (update after project close).
I never heard L1,L2,L3 in my project management study. Is this concept come from some well-known PM regulation or just this company's policy?
This is probably Company Policy.
For project schedules, Levels L1 to ~L6 normally refer to the levels of detail of contemporaneous schedules. These are defined (with some variations) in a few different sources. The only "PM Regulation" that springs to mind is the AACE International Recommended Practice (though it's not a formal standard). L1 may be a short table of milestones corresponding to "Top Management Summary," while L2 may be a 1-page Gantt chart "Project Management Summary." A level of detail of at least L3/L4 is normally required to obtain a valid critical path (i.e. logic-driven schedule), while L6 may correspond to a detailed deliverable register of a particular contractor during contract execution. Progressive development of project scope leads to the development of additional schedule detail levels after project initiation, though ALL levels are normally updated for use by different stakeholders.
It appears this company has taken to leaving the higher levels behind (not updated, frozen like a baseline) as progressive levels of detail are defined. There are worse practices.
I've never heard of L1, L2, L3... convention, and I suspect it is peculiar to that company - it is the kind of thing that ought to show up in the company's Organizational Process Assets.
The closest thing that come to my mind is that in the capital investment control system (ECPIC), the US Government records three dates for every event.
On the other hand, ECPIC largely ignores charters, while the system you're describing (L1, L2,...) seems oddly rooted on charter date. Given that the charter is at the open end of the cone of uncertainty, I'm not convinced of the value of tracking schedule variance at that granularity that early in the project. I'm not skeptical - I've seen some studies that assert that you have a 60% confidence in project success at roughly the charter milestone, and that might align with the system you describe. But I'm not yet convinced.
