True Lies - Project Estimation

According to the latest results of the famous study by The Standish Group about the failures of projects (Chaos Report), "44% of projects were challenged which are late, over budget, and/or with less than the required features and functions and 24% failed which are cancelled prior to completion or delivered and never used".

True Lies, copyright by 20th Century Fox Universal Pictures

But based on my wild guess (a very personal view), there are other "intended" reasons for the challenges/failures and I called these as "True Lies":

1. The project manger do knows the actual cost (at least, he/she knows the reliable estimate) of the project. But just because if he/she provides the actual estimate, he/she will never get the project approved (or he/she will be out of the job immediately). The only way is, therefore, provides an "acceptable" estimate (acceptable means the figures closed to the management expectation, no matter it is reasonable or not).
2. No matter what kind of project planning methodologies such as COCOMO, Function Points Analysis, Delphi techniques, and etc, all such methods are ballpark figures only (similar to sales forecast). The larger and the more complex the project, the higher the uncertainty (i.e. the degree of deviation). An estimate can only be accurate when the project is completed (or if there is same past project portfolios for reference). In reality, the project manager has only very limited resources to conduct proper planning (in terms of sufficient time, adequate resources and relevant past project portfolio reference). As a result, the degree of deviation (the error rate) should be inevitably higher.
3. For service providers, if they (salespersons, of course) quote the "true and realistic" estimates of project such as "half-year project timeline vs. the customer expectation of two months" for a tender, they won't have a chance to get the contract. In this case, other than the "budget" part (which affect the sales bonus/commission), the salesperson would only provide the "true lies" estimates (scope, quality, schedule and etc.) according to the customer's expectation, no matter they are achievable or not. The goal is to "get it first, fix it later", a kind of undesirable but inevitable ideology generated by the so-called "open market".

So when a project is kicked-off based on "true lies" estimates, it is another topic (or another big topic for a textbook) of the way of handling/managing it.