**3.1 Data collection**

From two financial institutions populations (3822 conventional financial institutions and 794 Islamic financial institutions), we chose two samples of banks that are located in 56 countries<sup>1</sup> whose banking systems integrate conventional as well as Islamic banks during the period (2010–2022). Based on qualitative and quantitative filtration criteria, we excluded specific, mutated, non-banking institutions and banks for which data is not available and added non-purely conventional or Islamic banks. Afterward, we filtered the remaining banks for each type until each CB had its Islamic counterpart in the same country. Therefore, we obtained two smaller sample sizes than those of the original populations. The cited conditions led us to eliminate 3642 conventional financial institutions and 514 Islamic financial institutions to end up with two equal samples, made up of 180 banks each.
