From:

http://hbr.org/2002/11/the-flaw-of-averages/ar/1

Show Me the Number

• Executives’ desire to work with “a number,” to plug in an average figure, is legendary. But whenever an average is used to represent an uncertain quantity, it ends up distorting the results because it ignores the impact of the inevitable variations. Averages routinely gum up accounting, investments, sales, production planning, even weather forecasting. Even the Generally Accepted Accounting Principles sanction the “flaw,” requiring that uncertainties such as bad debt be entered a s single numbers.

Insisting on using averages to determine if a schedule is good or bad is flawed theory,  not even a probabilistic distribution would do it, projects are different and unique.

http://www.ronwinterconsulting.com/DCMA_14-Point_Assessment.pdf

I do not see there the basic requirement that in order for a schedule to be of value in complex projects it must be continuously monitored by in-house personnel at the jobsite, not at a remote location.  On the contrary I have seen specifications mandating the use a so called outside expert,  yes outside, some flight by night scheduler when in-house would be much better.  The outside expert should be used only if needed to assist the in-house personnel but not as a substitute. 

Beware of the false prophets, there is no such thing as a magic bullet that will cure all ailments. I do not believe a doctor would prescribe the same medicine to all patients, what might cure the statistical majority might kill a particular patient. 

I would say Construction Sector and Defence are different animals.  Scheduling tools might be similar but how and when is another thing. 

About how:

At times it is not the size of the job but the complexity, we have managed mutistorey buildings with simple Gantt up to 20 stories on a single page including S Curve superimposed, it is repetitive and once the tempo is established is easy to control.  Each bar would represent a trade/subcontract and would display all floor levels timescaled within the same bar.  On the other hand for jobs such as Municipal Waste Water Treatment Plant I cannot imagine without the CPM schedule. 

For the Construction Sector we have several tools such as unit-job-costing that is a better fit than Earned Value to the extent at home I know no-one in the Construction Business that uses EVM in substitution to unit-job-costing that provides extra information.   Unit-job-costing along with the CPM gives us more information than EVM that is embedded in most software.   Ideally it would be desirable for software integrate unit costing with the CPM but the tendency to require different software for every other job makes it impractical in our business.

For defence development programs although I have never done work for development jobs I suspect EVM is a must have even for small development jobs.  Here unit-job-costing might not be applicable. Perhaps IT is similar to Defence sector in this regard, perhaps not always as creative work might be difficult to plan and control.

At the moment I do not use EVM and probably will never use it.  Earned Schedule is supposed to be an improvement over traditional EVM and if so I hope it will be adopted on the industries that have a need for it.

About when:

From:

http://www.ricardo-vargas.com/articles/earnedvaluecontrol/

• - "According to prior quotations, we can also see that in all three cases, there was an active participation of the planning departments of the business unit. However, this participation was different in each construction site. We can imply that the success of construction site 1, concerning the implantation of the tool, is directly linked to a strong presence of the professionals of planning department."

I would say it is not enough to start early but also to have strong presence of the professionals of planning department.  I provide scheduling services to various contractors but it is a mere document of not much value if there is no in-house presence at the jobsite that use it. 

Keep in mind this is an article related to the Construction Sector.