diff --git a/DESCRIPTION b/DESCRIPTION
index 5676796..b70950f 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: MungeSumstats
 Type: Package
 Title: Standardise summary statistics from GWAS
-Version: 1.13.2
+Version: 1.13.3
 Authors@R:
     c(person(given = "Alan",
            family = "Murphy",
diff --git a/NEWS.md b/NEWS.md
index 3ee7a90..7d1c822 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,11 @@
+## CHANGES IN VERSION 1.13.3
+
+### 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 1.13.2
 
 ### New features
diff --git a/R/check_allele_flip.R b/R/check_allele_flip.R
index 86cf1da..0914423 100644
--- a/R/check_allele_flip.R
+++ b/R/check_allele_flip.R
@@ -96,6 +96,7 @@ check_allele_flip <- function(sumstats_dt, path,
         sumstats_dt[is.na(ref_gen_allele), match_type := TRUE]
         sumstats_dt[A1 == ref_gen_allele, match_type := TRUE]
         sumstats_dt[A2 == ref_gen_allele, match_type := FALSE]
+        print(sumstats_dt)
         # drop cases that don't match either
         if (allele_flip_drop &&
             nrow(sumstats_dt[A1 != ref_gen_allele &
diff --git a/R/format_sumstats.R b/R/format_sumstats.R
index 4a6a619..1310bb7 100644
--- a/R/format_sumstats.R
+++ b/R/format_sumstats.R
@@ -486,7 +486,7 @@ format_sumstats <- function(path,
         #### Check 40:Check for log10 p instead of p ####
         sumstats_return <-
           read_log_pval(sumstats_dt = sumstats_return$sumstats_dt)
-
+ 
         #### Check 2:Check for effect direction ####
         sumstats_return <-
           infer_effect_column(
diff --git a/R/get_genome_build.R b/R/get_genome_build.R
index 3011b60..e2b6a36 100644
--- a/R/get_genome_build.R
+++ b/R/get_genome_build.R
@@ -181,6 +181,7 @@ get_genome_build <- function(sumstats,
                                on = c("SNP"="SNP","pos"="BP","seqnames"="CHR"),
                                nomatch = FALSE
           ])
+        
         if (num_37 > num_38) {
           ref_gen_num <- num_37
           ref_genome <- "GRCH37"
@@ -221,11 +222,12 @@ get_genome_build <- function(sumstats,
                                  "ref_allele"="A2","alt_alleles"="A1"),
                           nomatch = FALSE
         ])
-      if(num_a2>=num_a1){
+
+      if(num_a1>=num_a2){
         message("Effect/frq column(s) relate to A2 in the inputted sumstats")
         #this is what MSS expects so no action required
         switch_req <- FALSE
-      }else{#num_a2<num_a1
+      }else{#num_a1<num_a2
         message("Effect/frq column(s) relate to A1 in the inputted sumstats")
         switch_req <- TRUE
       }
diff --git a/R/infer_effect_column.R b/R/infer_effect_column.R
index 524019b..2529769 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,
@@ -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]
           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
diff --git a/longtests/testthat/test-infer_effect_column.R b/longtests/testthat/test-infer_effect_column.R
index 4508f4a..c88ca61 100644
--- a/longtests/testthat/test-infer_effect_column.R
+++ b/longtests/testthat/test-infer_effect_column.R
@@ -63,15 +63,15 @@ test_that("Test infer effect column function works", {
     )
     
     
-    #finally check if the ref genome can be used to infer rather than being told in 
-    #eff/frq cols - just subset for speed
+    #finally check if the ref genome can be used to infer rather than being 
+    #told in eff/frq cols - just subset for speed
     snps <- c("rs11210860","rs34305371","rs1008078","rs11588857","rs1777827",
               "rs76076331","rs2457660","rs10496091","rs4851251","rs12987662",
               "rs10930008","rs301800","rs2568955","rs61787263","rs2992632",
               "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.