It indicates that when you knock out the gene, the cell line grows faster. For example, TP53 has a positive score in most p53-wt cell lines. However, considerable caution should be used interpreting positive scores. We’ve found that many outgrowths in CRISPR data appear to be random. For example, in some cases outgrowth occurs for only one guide in one replicate, or occurs for unexpressed genes. Any event that grants a fitness advantage can cause clonal outgrowth and may have nothing to do with the targeted gene.