**3. Methodological aspects**

Given the lack of an exhaustive and up-to-date database that integrates all conventional and Islamic banks' information worldwide and their FP evolution, the generalization of the impacts resulting from the comparative results remains a challenge. Moreover, there are no big data sets that contain BIG4s and non-BIG4s EA characteristics worldwide, nor is there an exhaustive list of their clients. Furthermore, the correlation between the EAC and the banks' FP is generally subject to regional and behavioral rules with no constant or compliant impacts since they are dependent on law systems that differ from one country to another as well as people's behaviors that differ from one person/stakeholder to another. Because of the scientific gap between the theoretical cumulation and the unfounded exceptions to the empirical reality,

*How to Successfully Select the Best-Performing Bank Based on the Best Auditor's… DOI: http://dx.doi.org/10.5772/intechopen.113201*

maximizing the bank's FP means the selection of a good EAC and the selection of a good bank type based on a good EAC in the case of comparative studies. This remains an open debate for arbitration. That is why we insisted on using a demonstrative approach. First, we present the data collection. Next, we describe the search variables. Finally, we show the models to be estimated.
