However, a 2000 Thomas Miles document did not reveal any impact on total employment, but found that acceptance of the implied exception of the contract had the effect of increasing the use of temporary work by up to 15%.  David Author`s subsequent work in the mid-2000s identified several errors in the Miles methodology, found that the implied exemption from the contract reduced total employment from 0.8 to 1.6%, and confirmed the outsourcing phenomenon identified by Miles, but also found that At-Will`s unauthorized exceptions had no statistically significant influence.  The author and colleagues found later in 2007 that the good faith exception has the effect of reducing workflows and increasing labour productivity, but that overall factor productivity is decreasing.  In other words, employers forced to find “good faith” to lay off an employee tend to automate operations to avoid hiring new employees, but also to suffer from overall productivity due to increasing difficulties in laying off unproductive employees. Eleven U.S. states have recognized a violation of a tacit confederation for fair faith and fair trade as an exception to all-you-can-eat employment.   States are: Implicit contracts: employers are prohibited from dismissing an employee if a tacit contract is entered into between them, whether or not there is a legal document. It can be difficult to prove the validity of such an agreement and the burden on the worker is difficult. Your employer`s guideline book or Recruitment Manual may indicate that employees are not at will and can only be fired for a good cause. The doctrine of will work may be abrogated by an explicit contract or a status of the civil service (in the case of state agents). 34% of all American workers appear to have the protection of some kind of “just cause” or objectively reasonable obligation to dismiss, which excludes them from the pure “all-you-can-eat” category, including the 7.5% of non-union workers in the private sector, the 0.8% of non-union workers in the private sector protected by union contracts, the 15% of non-union workers in the private sector with individual express employment contracts , and the 16% of total employment that, as public service employees, enjoy protection in the public service.
 Be careful if you sign employment contracts at your convenience, if you rely on your employer`s comments on the permanent job guaranteed to accept the job. For example, if you have an interview and the employer promises to give you a full year to learn the ropes, and you cannot be fired this year.