diff --git a/egs/wsj/s1/RESULTS b/egs/wsj/s1/RESULTS
index 23949745c..0d0d22d8f 100644
--- a/egs/wsj/s1/RESULTS
+++ b/egs/wsj/s1/RESULTS
@@ -110,7 +110,13 @@ Test set: | Eval92   |   Eval93  | Eval92   |  Eval93 |  Eval92   |   Eval93  |
 latrescore|   12.6       18.7      14.3       21.0        12.1         18.2
  [beam=15]|   12.5       18.7      14.3       20.9        11.7         18.2
 
-
+# Oracle lattice results:
+On Eval92 lattices generated with a bigram LM (from exp/decode_tri2a_bg_latgen_eval92)
+Lattices pruned with varying beam values:
+beam=0.01 %WER 16.13 [ 910 / 5641, 213 ins, 59 del, 638 sub ]
+beam=1    %WER 13.07 [ 737 / 5641, 171 ins, 46 del, 520 sub ]
+beam=5    %WER  6.38 [ 360 / 5641, 86 ins, 20 del, 254 sub ]
+beam=10   %WER  4.11 [ 232 / 5641, 53 ins, 9 del, 170 sub ]
 
 # Raw results:
 exp/decode_mono_tgpr_eval92/wer:%WER 31.38 [ 1770 / 5641, 108 ins, 386 del, 1276 sub ]
diff --git a/egs/wsj/s1/run.sh b/egs/wsj/s1/run.sh
index 1034b5592..2b9624aee 100644
--- a/egs/wsj/s1/run.sh
+++ b/egs/wsj/s1/run.sh
@@ -216,6 +216,7 @@ steps/train_tri2a.sh || exit 1;
  for year in 92 93; do
   scripts/decode.sh exp/decode_tri2a_bg_eval${year} exp/graph_tri2a_bg/HCLG.fst steps/decode_tri2a.sh data/eval_nov${year}.scp 
   scripts/decode.sh exp/decode_tri2a_bg_latgen_eval${year} exp/graph_tri2a_bg/HCLG.fst steps/decode_tri2a_latgen.sh data/eval_nov${year}.scp 
+  scripts/latoracle.sh exp/decode_tri2a_bg_latgen_eval${year} data/eval_nov${year}.txt exp/decode_tri2a_bg_latoracle_eval${year}
   scripts/latrescore.sh exp/decode_tri2a_bg_latgen_eval${year} data/G_bg.fst data/G_tg.fst data/eval_nov${year}.txt exp/decode_tri2a_bg_rescore_tg_eval${year} 
   scripts/latrescore.sh exp/decode_tri2a_bg_latgen_eval${year} data/G_bg.fst data/G_tg_pruned.fst data/eval_nov${year}.txt exp/decode_tri2a_bg_rescore_tg_pruned_eval${year} 
   scripts/latrescore.sh exp/decode_tri2a_bg_latgen_eval${year} data/G_bg.fst data/G_bg.fst data/eval_nov${year}.txt exp/decode_tri2a_bg_rescore_bg_eval${year} 
diff --git a/egs/wsj/s1/scripts/latoracle.sh b/egs/wsj/s1/scripts/latoracle.sh
new file mode 100755
index 000000000..67444ea2e
--- /dev/null
+++ b/egs/wsj/s1/scripts/latoracle.sh
@@ -0,0 +1,64 @@
+#!/bin/bash
+# Copyright 2011 Microsoft Corporation1 Gilles Boulianne
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+# THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+# WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
+# MERCHANTABLITY OR NON-INFRINGEMENT.
+# See the Apache 2 License for the specific language governing permissions and
+# limitations under the License.
+
+
+
+if [ $# != 3 ]; then
+   echo "Usage: scripts/latoracle.sh <input-decode-dir> <transcript-text-file> <output-decode-dir>"
+   exit 1;
+fi
+
+. path.sh || exit 1;
+
+
+inputdir=$1  # e.g. /pub/tmp/kaldi2011/dpovey/decode_tri1_latgen/
+transcript=$2 # e.g. data_prep/test_sep92_trans.txt
+dir=$3  #eg exp/decode_tri1_latgen
+
+mkdir -p $dir
+
+# Create reference transcriptions and lattices
+cat $transcript | sed 's:<NOISE>::g' |  sed 's:<SPOKEN_NOISE>::g' > $dir/test_trans.filt
+cat $dir/test_trans.filt | \
+  scripts/sym2int.pl --ignore-first-field data/words.txt | \
+  string-to-lattice "ark:$dir/test_trans.lats" 2>$dir/string-to-lattice.log
+
+# Symbols that don't count as errors
+echo "<s>"    > $dir/ignore.txt
+echo "</s>"  >> $dir/ignore.txt
+echo "<UNK>" >> $dir/ignore.txt
+
+# Loop over pruning beams
+inv_acwt=10
+acwt=`perl -e "print (1.0/$inv_acwt);"`
+for beam in 0.01 1 5 10; do
+
+  echo "Pruning $inputdir"'/*.lats.gz'" with invacwt=$inv_acwt and beam=$beam"
+  lattice-prune --acoustic-scale=$acwt --beam=$beam \
+    "ark:gunzip -c $inputdir/*.lats.gz|" "ark,t:|gzip -c>$dir/lats.pruned.gz" \
+       2>$dir/prune.$beam.log
+
+  echo "Computing oracle error rate w/r $transcript"
+  lattice-oracle --word-symbol-table=data/words.txt --wildcard-symbols-list=$dir/ignore.txt \
+     "ark:$dir/test_trans.lats" "ark:gunzip -c $dir/lats.pruned.gz|" "ark,t:$dir/oracle${beam}.tra" \
+       2>$dir/oracle.$beam.log
+  
+  cat $dir/oracle${beam}.tra | \
+   scripts/int2sym.pl --ignore-first-field data/words.txt | \
+   sed 's:<s>::' | sed 's:</s>::' | sed 's:<UNK>::g' | \
+    compute-wer --text --mode=present ark:$dir/test_trans.filt  ark,p:- | tee $dir/wer_${beam}
+done
+