**3. Research methodology**

### **3.1 Methodological aspects**

### *3.1.1 Data collection*

Two samples were taken from two reference populations, which are made up of 683 participating financial institutions and 2974 conventional financial institutions. The selection of banks is made in 30 countries,<sup>1</sup> whose banking systems include Islamic and conventional banks, over the period 2019–2022. However, we have

<sup>1</sup> Algeria (3,3), Bahrain (6,6), Bangladesh (4,4), Canada (1,1), Egypt (4,4), France (2,2), India (2,2), Indonesia (4,4), Jordan (4,4), Kazakhstan (3,3), Kuwait (6,6), Lebanon (2,2), Luxembourg (2,2), Malaysia (7,7), Nigeria (2,2), Oman (3,3), Pakistan (8,8), Qatar (6,6), Saudi Arabia (9,9), Senegal (3,3), Singapore (4,4), South Africa (1,1), Sri Lanka (1,1), Sudan (5,5), Thailand (1,1), Tunisia (2,2), Turkey (5,5), United Arab Emirates (5,5), United Kingdom (5,5), and USA (2,2).

*Impacts of Board Quality on Financial Performance in Conventional… DOI: http://dx.doi.org/10.5772/intechopen.112089*

excluded all specific financial institutions subject to specific regulations<sup>2</sup> . The observations chosen are all purely conventional or participatory banks. Moreover, due to difficulties in collecting information on FP and BOD, we excluded banks marked with missing data. We also ignored the mutated banks and conventional banks that added Islamic services. These restrictions led us to eliminate 571 participatory financial institutions and 2862 conventional financial institutions. Thereafter, we equalized the two samples on the basis of the qualitative and quantitative filtering criteria (equality of the samples, type of activity, similarity of the country of origin, and width of the bank) to finally obtain 112 banks in each sample.
