Update README.md

README.md

@@ -31,7 +31,7 @@ The compiled `metal` executable will be installed into `build/bin` directory.
 - 2017-12-21
   - Correction for sample overlap in sample size weighted meta-analysis (developed by Sebanti Sengupta). First, METAL estimates the number of individuals that are common among two or more studies based on Z-statistics from each study. Then, METAL adjusts for sample overlap when calculating overall Z-statistics by correcting the weights with the estimated number of individuals in common. 
 
-    To enable correction for sample overlap in your sample size weighted meta-analysis, use `OVERLAP ON` command (valid only with `SCHEME SAMPLESIZE`). By default, METAL uses Z-statistics <1 for esimating the number of individuals that are common among studies. To change this threshold, use `ZCUTOFF [number]` command. The `N` column in the result file will store sample size corrected for overlap between studies.
+    To enable correction for sample overlap in your sample size weighted meta-analysis, use `OVERLAP ON` command (valid only with `SCHEME SAMPLESIZE`) before any `PROCESS` commands. By default, METAL uses Z-statistics <1 for esimating the number of individuals that are common among studies. To change this threshold, use `ZCUTOFF [number]` command. The `N` column in the result file will store sample size corrected for overlap between studies.
 
     More information on this specific method can be found on our wiki: https://genome.sph.umich.edu/wiki/METAL_Documentation#Sample_Overlap_Correction