In many cases we may have several approaches to realise a precision measurement. It is very important to decide on an optimal measurement approach or plan in order to obtain effectively high-fidelity results. A measurement process may involve many kinds of error factors which vary in different measurement plans. This would make the selection of the most appropriate approach difficult. Currently, prior knowledge of the relationship between measured variables and error factors, and statistical methods are typically used for such selection. In many cases, however, the relationship may not be clear, due to non-quantitative factors being involved. To solve the problem, a new method that is based on fuzzy set theory is proposed. In this method, membership grades are established and grades to the quasi-perfect plan are maximised. Mathematical models are established and the concept of a quasi-perfect measurement plan is proposed. Experimental testing is presented in order to demonstrate the effectiveness of the proposed method.