diff --git a/DESCRIPTION b/DESCRIPTION
index 0626b99..6eb6293 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: MungeSumstats
 Type: Package
 Title: Standardise summary statistics from GWAS
-Version: 1.12.0
+Version: 1.12.1
 Authors@R:
     c(person(given = "Alan",
            family = "Murphy",
diff --git a/NEWS.md b/NEWS.md
index 394a403..63ffd86 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,11 @@
+## CHANGES IN VERSION 1.12.1
+
+### Bug fix
+* Bug fix for check 3 in infer effect column - previously A1 & A2 were swapped 
+when there were more matches for the ref genome in A1 rather than A2 which was 
+incorrect. Corrected now so it will only be flipped when A2 has more matches 
+to the reference genome.
+
 ## CHANGES IN VERSION 1.11.10
 
 ### New features
diff --git a/R/infer_effect_column.R b/R/infer_effect_column.R
index 524019b..d24f20b 100644
--- a/R/infer_effect_column.R
+++ b/R/infer_effect_column.R
@@ -11,7 +11,7 @@
 #' mentioned, if found then  we know the direction and should update A1/A2 
 #' naming so A2 is the effect column. We can look for such columns by getting 
 #' every combination of A1/A2 naming and effect/frq naming.
-#' 3. If note found in 2, a final check should be against the reference genome, 
+#' 3. If not found in 2, a final check should be against the reference genome, 
 #' whichever of A1 and A2 has more of a match with the reference genome should 
 #' be taken as **not** the effect allele. There is an assumption in this but is 
 #' still better than guessing the ambiguous allele naming.
@@ -49,13 +49,14 @@ infer_effect_column <-
       # vs those that are interpretable
       colnames(mapping_file) <- toupper(colnames(mapping_file))
       allele_mapping <- mapping_file[mapping_file$CORRECTED %in% c('A1','A2'),]
-      ambig_allele_map <- allele_mapping[grepl('1',allele_mapping$UNCORRECTED)|
-                                           grepl('2',allele_mapping$UNCORRECTED),]
+      ambig_allele_map <- 
+        allele_mapping[grepl('1',allele_mapping$UNCORRECTED)|
+                         grepl('2',allele_mapping$UNCORRECTED),]
       unambig_allele_map <- 
         allele_mapping[!(grepl('1',allele_mapping$UNCORRECTED)|
                            grepl('2',allele_mapping$UNCORRECTED)),]
-      #as long as the sumstats contains 1 unambiguous allele column MSS will work
-      #as expected
+      #as long as the sumstats contains 1 unambiguous allele column MSS will
+      #work as expected
       unambig_cols <- intersect(unambig_allele_map$UNCORRECTED,
                                 toupper(column_headers))
       ambig_cols <- intersect(ambig_allele_map$UNCORRECTED,
@@ -68,11 +69,11 @@ infer_effect_column <-
         #get corrected name for unambig 
         unambig_corrcted <- 
           unique(allele_mapping[allele_mapping$UNCORRECTED %in% unambig_cols,
-                                ]$CORRECTED)
+          ]$CORRECTED)
         #check if any ambig are to the same allele
         ambig_corrcted <- 
           unique(allele_mapping[allele_mapping$UNCORRECTED %in% ambig_cols,
-                                ]$CORRECTED)
+          ]$CORRECTED)
         #overlap?
         ambig_corrcted_rnme <- 
           ambig_corrcted[ambig_corrcted %in% unambig_corrcted]
@@ -81,13 +82,14 @@ infer_effect_column <-
           message("Renaming ambiguous allele columns so they won't be used")
           #get the related ambig naming and change there name so won't be used
           ambig_uncorrcted_rnme <- 
-            ambig_allele_map[ambig_allele_map$CORRECTED %in% ambig_corrcted_rnme,
-                             ]$UNCORRECTED
+            ambig_allele_map[ambig_allele_map$CORRECTED %in% 
+                               ambig_corrcted_rnme,]$UNCORRECTED
           #now rename any matches in sumstats
           chng_nmes <- column_headers[toupper(column_headers) %in% 
-                                       ambig_uncorrcted_rnme]
+                                        ambig_uncorrcted_rnme]
           for(chng_i in chng_nmes){
-            data.table::setnames(sumstats_dt, chng_i, paste0(chng_i,"_INPUTTED"))
+            data.table::setnames(sumstats_dt, chng_i, 
+                                 paste0(chng_i,"_INPUTTED"))
           }
         }
       } else if (length(unambig_cols)==0 && length(ambig_cols)>=2){
@@ -95,7 +97,7 @@ infer_effect_column <-
         #less than 2 in total means allele info is missing which MSS can try fill
         #in later
         message("Allele columns are ambiguous, attempting to infer direction")
-        #get names for allele mared eff/frq columns
+        #get names for allele marked eff/frq columns
         eff_frq_allele_matches <- get_eff_frq_allele_combns()
         #now look for matches in sumstats
         fnd_allele_indicator <- 
@@ -107,10 +109,10 @@ infer_effect_column <-
           a1_mtch <- sum(grepl("A1",fnd_allele_indicator))
           a2_mtch <- sum(grepl("A2",fnd_allele_indicator))
           if(a2_mtch>=a1_mtch){
-            message("Effect/frq column(s) relate to A2 in the inputted sumstats")
+            message("Effect/frq column(s) relate to A2 in the sumstats")
             #this is what MSS expects so no action required
           }else{#a2_mtch<a1_mtch
-            message("Effect/frq column(s) relate to A1 in the inputted sumstats")
+            message("Effect/frq column(s) relate to A1 in the sumstats")
             #this is the opposite to what MSS expects so switch A1/A2 naming
             #first get corrected names for allele columns then switch
             for (headerI in seq_len(nrow(mapping_file))) {
@@ -146,9 +148,9 @@ infer_effect_column <-
               ref_genome = ref_genome
             )
             if(is.logical(switch_req)){
-              message(paste0("Found direction from matchine reference genome - N",
-                             "OTE this assumes non-effect allele will macth the ",
-                             "reference genome"))
+              message(paste0("Found direction from matching reference genome -",
+                             " NOTE this assumes non-effect allele will match ",
+                             "the reference genome"))
               if(isTRUE(switch_req)){
                 #swap A1 and A2
                 #this is the opposite to what MSS expects so switch A1/A2 naming
@@ -184,4 +186,4 @@ infer_effect_column <-
     }else {
       return(sumstats_dt)
     }
-  }    
+  }    
\ No newline at end of file
diff --git a/longtests/testthat/test-infer_effect_column.R b/longtests/testthat/test-infer_effect_column.R
index 4508f4a..2541042 100644
--- a/longtests/testthat/test-infer_effect_column.R
+++ b/longtests/testthat/test-infer_effect_column.R
@@ -71,7 +71,7 @@ test_that("Test infer effect column function works", {
               "rs11689269","rs11690172")
     d <- copy(b)
     data.table::setnames(d,"BETA1","BETA")
-    d_for <- MungeSumstats::format_sumstats(d[SNP %in% snps,], return_data = TRUE, 
+    d_for <- MungeSumstats::format_sumstats(d[!SNP %in% snps,], return_data = TRUE, 
                                             on_ref_genome = TRUE,
                                             #all just make MSS run faster
                                             ref_genome = 'GRCh37',
@@ -82,7 +82,7 @@ test_that("Test infer effect column function works", {
     data.table::setkey(b_renamed_for,"SNP")
     data.table::setkey(d_for,"SNP")
     testthat::expect_equal(
-      all.equal(b_renamed_for[SNP %in% snps], d_for,
+      all.equal(b_renamed_for[!SNP %in% snps], d_for,
                 ignore.col.order = TRUE),
       TRUE
     )
diff --git a/man/infer_effect_column.Rd b/man/infer_effect_column.Rd
index a5a6142..5cd1444 100644
--- a/man/infer_effect_column.Rd
+++ b/man/infer_effect_column.Rd
@@ -64,7 +64,7 @@ tested (unambiguous so fine for MSS to handle as is).
 mentioned, if found then  we know the direction and should update A1/A2
 naming so A2 is the effect column. We can look for such columns by getting
 every combination of A1/A2 naming and effect/frq naming.
-\item If note found in 2, a final check should be against the reference genome,
+\item If not found in 2, a final check should be against the reference genome,
 whichever of A1 and A2 has more of a match with the reference genome should
 be taken as \strong{not} the effect allele. There is an assumption in this but is
 still better than guessing the ambiguous allele naming.