# Sensory Panel Performance Evaluation--Comprehensive Review of Practical Approaches
## 4 Methods, Models and Frameworks in Sensory Panel Evaluation  
### Classification of Panel Performance Tools according to Sensory Method Types  
Panel performance evaluation approaches might vary depending on the type of sensory tests applied by the assessors. It can be a critical and controversial point in methodology, since the most detailed measuring systems were created for descriptive analysis methods, such as sensory profile or quantitative descriptive analysis (QDA) [41]. However, in industrial laboratories and in product competitions several other types of test methods are performed. For these methods, in some cases, the relevant international standards provide guidance through some practical examples and with a list of further references. It is notable that the ISO subcommittee for sensory analysis decided to create a working document (and later on hopefully a new ISO standard) for panel performance measurement, especially for those methods which are different from the traditional descriptive analysis. In the following sections, the authors go through the major types of sensory test methods, and the possible panel performance measuring tools. Difference tests seem to be rather easy and suitable methods for panelist evaluation, since due to the basic idea of difference testing in most cases there is a good (valid) and a wrong (invalid) answer. However, even these simply constructed procedures might be challenging to the practitioner if all relevant criteria should be met [42]. One of the standards is fully dedicated to the statistical analysis of the responses and their graphical representation [43]. The sequential analysis is a systematic procedure of plotting the panelists' correct responses versus the number of total tests performed. The idea of this approach is to create a graphical representation of the statistical truth behind the test outcome analysis [8]. If the laboratory is computerized, the panel leader is able to monitor the responses online, and has the possibility to end the test session (if a large number of good response are collected), or can decide to continue the session for a longer time. In case of triangle tests, the major focus is usually on the general outcome of the test (are the samples significantly different or not), but in some cases the individual performance is also measured. For almost all difference tests, the international standards (ISO) specify those procedures as suitable methods for panelist selection and panelist training. This recommendation is usually found in the scope section. These test methods are the following: 'A'--Not 'A' test, duo-trio test, triangle test, tetrad test, 2 out of 5 test and paired comparison test. Some of these methods are harmonized at a national level, e.g., the tetrad test is just a sub-section of ISO 6658, but a whole ASTM is dedicated to the description of it. Ranking tests are based on the relatively simple task to create an order among samples based on a single attribute. The complexity and difficulty of these tests comes from the relative similarity of the test samples (e.g., product re-formulation studies, sweetener replacement project, etc.). Panel leaders might apply ranking tests in order to test the ability of panelist to re-create a known order of the samples. If one sensory parameter (e.g., the amount of the applied sweetener) is given as an experimental factor, the panel leader will be able to present each panelist with a randomized sample set, and assessors will have to arrange those samples in the right order. Statistically, in this case the Page test is recommended, which measures the similarity of the rank order given by the panelists and the expected rank order. Page test results will give an insight into the overall performance of the panel at the pre-determined significance level. In this case, first the rank sums of the samples are calculated. Thereafter, each rank sum is multiplied with that value, where the sample is positioned in the theoretical order.