The reliability of the app refers to how much you can depend on its measures being trustworthy or accurate.
A common way to determine this, is to show that its measures are consistent over time. If you complete a BrainEye test on more than occasion you would expect to get the same results each time, unless of course, something had happened in the meantime to alter the way your brain functions. To measure the apps reliability, BrainEye conducted studies that tested the same group of people at two different timepoints and then determined the relationship between the two sets of results.
Using a well-known statistical tool, the intra-class correlation coefficient (ICC), BrainEye found that the ICC of its measures ranged from 0.7 to 0.9. This means that the app is very reliable and can be trusted to accurately measure movement of your eyes.