**1. Introduction**

In natural sciences, the standardization of operation procedures, aiming at methodologies and the reliability as well as the validity of resulting data, is most important.

Thinking of test settings in sensory science, especially to control and monitor panelist and panel performance during the panel work in defined test settings is necessary. In the context of sensory evaluation of olive oil specifically, several official requirements do exist—on the one hand the EEC regulation 2568/91 [1], as amended, as well as several underlying documents and guidelines from the International Olive Council (IOC) [2–4] and moreover the general EN ISO/IEC 17025 regulations for any kind of testing laboratories [5].

Data quality must be the overriding objective in natural sciences and therefore is indispensable. Assuring a high data quality during data collection and assessment requires a clear focus on "data reliability" (high precision → same/similar results) and "data validity" (high accuracy → correct results). Well known is that one can gain high precision in measuring something, but at the same time can miss the target meaning that results are precise, but not correct. So, overall high data quality can only be achieved, if data are on the one hand precise (reliable) and at the same time as well accurate (valid).


Factors that might have a negative impact on data quality in sensory science are manifold. They can be related to the execution of the general procedure (test methodology), to the handling of test samples (blinding, distribution, temperature), to training and monitoring aspects of panelists and panels, to statistical analysis and data management as well as to the test infrastructure.

All above-named regulations and guidelines have in common to standardize and control procedures and finally to minimize "noise" in resulting data. This is helpful and valuable, but nevertheless, not all possible and focused so-called "influencing factors" cause a similar or even a relevant impact on data quality—some of them, presupposing a specific framework of instructions and settings, even have none.
