A descriptible analysis of the characteristics of the studies and statistical methods used was carried out. This is a descriptive check and all results are shown as a percentage. The data was analyzed with SPSS 15.0 software. Another way to conduct reliability tests is the use of the intraclass correlation coefficient (CCI).  There are several types, and one is defined as “the percentage of variance of an observation because of the variability between subjects in actual values.”  The ICC area can be between 0.0 and 1.0 (an early definition of CCI could be between 1 and 1). CCI will be high if there are few differences between the partitions that are given to each item by the advisors, z.B. if all advisors give values identical or similar to each of the elements. CCI is an improvement over Pearsons r`displaystyle r` and Spearmans `displaystyle `rho`, as it takes into account differences in evaluations for different segments, as well as the correlation between Denern. Very often, contract studies are an indirect attempt to validate a new system or evaluation instrument. In other words, in the absence of a final criterion variable or a “gold standard,” the accuracy of a scale or instrument is assessed by comparing its results when used by different advisors.
Here, we can use methods that address the problem of real anxiety – to what extent do ratings reflect the true property we want to measure? Total 117 items (56%) a unique method used to evaluate the agreement, while 93 articles (44%) (two or more) methods used. The most popular statistical methods used to assess compliance in the 210 controlled and specialty articles are summarized in Table 1 and Table 2. Most articles (178 articles or 85%) The Bland-Altman (Limits of Agreement) method used to measure the equipment agreement. Out of 178 articles, 99 (56%) Bland-Altman method used alone to evaluate the agreement, while the rest (79 or 44%) combine the Bland-Altman method with another method. This study finds that the Bland-Altman method is the most popular method used in contract research. In some studies, there are still inappropriate applications of statistical methods. It is important for a physician or medical researcher to be aware of this problem, as misleading findings from inappropriate analyses compromise the quality of evidence, which will affect the quality of patient care in the future. Cohens Kappa measures the agreement between two advisors who classify each of the N elements into exclusion categories C. The definition of “Textstyle” is: Cohens Kappa- Coefficient () is a statistic used to measure reliability between advisors (and also the reliability of inter-raters) for qualitative (categorical) elements. It is generally accepted that this is a more robust indicator than a simple percentage of the agreement calculation, since the possibility of a random agreement is taken into account. There are controversies around Cohens Kappa because of the difficulty of interpreting the indications of the agreement. Some researchers have suggested that it is easier, conceptually, to assess differences of opinion between objects.  For more details, see Restrictions.