Schedule Review Based on Statistics

I always joke about phenomena in the planning profession.  There are two kinds of schedulers.  One is a guy creating a schedule, the other one is the guy reviewing the schedule.  However, there is no one using the schedule.  The one reviewing the schedule always think the other is to fool him and the schedule is not good.  On the other hand, the one creating the schedule always needs more time to finish the schedule to satisfy the reviewers instead of the users.

I think that some guys just get things way too complicated.  I don’t think any rule of thumbs can replace any knowledge about the scope of the work you are planning.  A professional Scheduler is like a superintendent with a specialty on analyzing the scheduling risk.  For example, if you work on a building project, you have to know the scope of work and plan a realistic schedule.  One the other hand, if you are to review the submitted schedule from contractor, you should know even more about the scope and contractor’s plan.  In my opinion, the statistics of the data from a schedule serves no relevance to the feasibility of a schedule.  A schedule can have a “reasonable’ data, however, it can reflect no realistic planning and wrong critical path.

However, I think that some percentage (statistics) requirements for the critical path in the spec are used to discourage the contractor from submitting a claim oriented schedule.  Normally, those percentages are set at a very conservative level such as 30%.  If a schedule really has high percentage numbers of activities on the critical path, it means the contractor is using too many “soft logics” in the schedule, which should be taken out or carefully justified.  In this case, the Scheduler’s knowledge about the scope is even more important.

On the other hand, this will serve a two edge sword.  Contractor’s delay will have the same impacts to the schedule also.  Honestly, I don’t think most contractors will try to do that based on my experiences.  As you know, contractors definitely will carry more schedule risk than owners.

Note: Soft logics are logics connected by preference, not inherent logics such as hard logics.