QuickPRS is an approximate version of MegaPRS. When running MegaPRS with SNP-based summary statistics, the first step is to use the reference panel to compute SNP-SNP correlations. QuickPRS skips this step and instead uses pre-computed SNP-SNP correlations. As a result, QuickPRS should be faster and easier to use than MegaPRS.
QuickPRS can be more accurate than MegaPRS. This reflects that the pre-computed correlations were generated using reference panels containing thousands of individuals, and should therefore be superior to correlations generated using smaller reference panels (e.g., constructed from the 1000 Genome Project data).
On the other hand, QuickPRS is less flexible than MegaPRS, because it can only be used with SNP-based data for human traits, and the user has limited choice over which SNPs to use. Note that we only recommend using QuickPRS when you have (valid) summary statistics for the majority of SNPs present in the pre-computed correlations. If you are missing statistics for a substantial proportion (e.g., more than 20%), you should consider switching to MegaPRS.
