I'm new to this forum and also not too well versed in statistics. We are working on an algorithm to predict the most likely causal gene from a group of genes of size n that only contains one true positive. If we rank all the genes in this group, we have X% probability of predicting the true causal gene in the top 10% of the ranked genes. In this situation where there is only one known true positive, how do we consider false positive rate? Or is there another metric we should consider using?