diff --git a/do-it.sh b/do-it.sh
index 84b384c..0d0b9fe 100755
--- a/do-it.sh
+++ b/do-it.sh
@@ -8,6 +8,13 @@ function DEBUG() {
 # enable/disable debugging output
 GITDM_DEBUG=${GITDM_DEBUG:-"off"}
 
+# determine if a given parameter is a date matching the format YYYY-MM-DD, 
+# i.e. 2013-09-13   This is used to decide if git should specify a start
+# date with '--since YYYY-MM-DD' rather than use an absolute changeset id
+function IS_DATE() {
+    [[ $1 =~ ^[0-9][0-9][0-9][0-9]\-[0-9][0-9]\-[0-9][0-9]$ ]]
+}
+
 GITBASE=${GITBASE:-~/git/openstack}
 RELEASE=${RELEASE:-havana}
 BASEDIR=$(pwd)
@@ -23,6 +30,9 @@ LP_STATS=${LP_STATS:-n}
 QUERY_LP=${QUERY_LP:-y}
 GERRIT_STATS=${GERRIT_STATS:-y}
 REMOVE_TEMPDIR=${REMOVE_TEMPDIR:-y}
+TIMESTAMP=`date`
+# brief header to prepend to all of the analysis results
+OUTPUT_HEADER="Statistics generated at ${TIMESTAMP}"
 
 if [ ! -d .venv ]; then
     echo "Creating a virtualenv"
@@ -53,6 +63,13 @@ if [ "$GIT_STATS" = "y" ] ; then
         while read project revisions excludes x; do
             DEBUG "Generating git commit log for ${project}"
             cd ${GITBASE}/${project}
+            # match possible dates of the format YYYY-MM-DD to use in 
+            # supplying git with a '--since DATE' paramter instead of a 
+            # range of changeset ids
+            if IS_DATE $revisions; then
+                DEBUG "Matched a git --since date of '${revisions}'"
+                revisions="--since ${revisions}"
+            fi
             git log ${GITLOGARGS} ${revisions} > "${TEMPDIR}/${project}-commits.log"
             if [ -n "$excludes" ]; then
                 awk "/^commit /{ok=1} /^commit ${excludes}/{ok=0} {if(ok) {print}}" \
@@ -66,9 +83,11 @@ if [ "$GIT_STATS" = "y" ] ; then
     grep -v '^#' ${CONFIGDIR}/${RELEASE} |
         while read project x; do
             DEBUG "Generating git stats for ${project}"
-            python gitdm -l 20 -n < "${TEMPDIR}/${project}-commits.log" > "${TEMPDIR}/${project}-git-stats.txt"
+            echo "${OUTPUT_HEADER}" > "${TEMPDIR}/${project}-git-stats.txt"
+            python gitdm -l 20 -n < "${TEMPDIR}/${project}-commits.log" >> "${TEMPDIR}/${project}-git-stats.txt"
             # also create a full dump with csv for further downstream processing
-            python gitdm -n -y -z -x "${TEMPDIR}/${project}-git-stats.csv" < "${TEMPDIR}/${project}-commits.log" > "${TEMPDIR}/${project}-git-stats-all.txt"
+            echo "${OUTPUT_HEADER}" > "${TEMPDIR}/${project}-git-stats.csv"
+            python gitdm -n -y -z -x "${TEMPDIR}/${project}-git-stats.csv" < "${TEMPDIR}/${project}-commits.log" >> "${TEMPDIR}/${project}-git-stats-all.txt"
         done
 
     DEBUG "Generating aggregate git stats for all projects"
@@ -76,7 +95,8 @@ if [ "$GIT_STATS" = "y" ] ; then
         while read project x; do
             cat "${TEMPDIR}/${project}-commits.log" >> "${TEMPDIR}/git-commits.log"
         done
-    python gitdm  -n -y -z -x "${TEMPDIR}/git-stats.csv" < "${TEMPDIR}/git-commits.log" > "${TEMPDIR}/git-stats.txt"
+    echo "${OUTPUT_HEADER}" > "${TEMPDIR}/git-stats.txt"
+    python gitdm  -n -y -z -x "${TEMPDIR}/git-stats.csv" < "${TEMPDIR}/git-commits.log" >> "${TEMPDIR}/git-stats.txt"
 fi
 
 if [ "$LP_STATS" = "y" ] ; then
@@ -97,11 +117,12 @@ if [ "$LP_STATS" = "y" ] ; then
 
     echo "Generating launchpad statistics"
     cd ${BASEDIR}
+    echo "${OUTPUT_HEADER}" > "${TEMPDIR}/${project}-lp-stats.txt"
     grep -v '^#' ${CONFIGDIR}/${RELEASE} |
         while read project x; do
             DEBUG "Generating launchpad stats for ${project}"
             grep -v '<unknown>' "${TEMPDIR}/${project}-bugs.log" |
-                python lpdm -l 20 > "${TEMPDIR}/${project}-lp-stats.txt"
+                python lpdm -l 20 >> "${TEMPDIR}/${project}-lp-stats.txt"
         done
 
     DEBUG "Generating aggregate launchpad stats for all projects"
@@ -110,8 +131,9 @@ if [ "$LP_STATS" = "y" ] ; then
         while read project x; do
             grep -v '<unknown>' "${TEMPDIR}/${project}-bugs.log" >> "${TEMPDIR}/lp-bugs.log"
         done
+    echo "${OUTPUT_HEADER}" > "${TEMPDIR}/lp-stats.txt"
     grep -v '<unknown>' "${TEMPDIR}/lp-bugs.log" |
-        python lpdm -l 20 > "${TEMPDIR}/lp-stats.txt"
+        python lpdm -l 20 >> "${TEMPDIR}/lp-stats.txt"
 fi
 
 if [ "$GERRIT_STATS" = "y" ] ; then
@@ -119,6 +141,13 @@ if [ "$GERRIT_STATS" = "y" ] ; then
     grep -v '^#' ${CONFIGDIR}/${RELEASE} |
         while read project revisions x; do
             cd "${GITBASE}/${project}"
+            # match possible dates of the format YYYY-MM-DD to use in 
+            # supplying git with a '--since DATE' paramter instead of a 
+            # range of changeset ids
+            if IS_DATE $revisions; then
+                DEBUG "Matched a git --since date of '${revisions}'"
+                revisions="--since ${revisions}"
+            fi
             git log ${revisions} |
                 awk '/^    Change-Id: / { print $2 }' |
                 split -l 100 -d - "${TEMPDIR}/${project}-${RELEASE}-change-ids-"
@@ -142,6 +171,13 @@ if [ "$GERRIT_STATS" = "y" ] ; then
         while read project revisions x; do
             DEBUG "Generating a list of commit IDs for ${project}"
             cd "${GITBASE}/${project}"
+            # match possible dates of the format YYYY-MM-DD to use in 
+            # supplying git with a '--since DATE' paramter instead of a 
+            # range of changeset ids
+            if IS_DATE $revisions; then
+                DEBUG "Matched a git --since date of '${revisions}'"
+                revisions="--since ${revisions}"
+            fi
             git log --pretty=format:%H $revisions > \
                 "${TEMPDIR}/${project}-${RELEASE}-commit-ids.txt"
         done
@@ -160,15 +196,17 @@ if [ "$GERRIT_STATS" = "y" ] ; then
 
     echo "Generating gerrit statistics"
     cd ${BASEDIR}
+    echo "${OUTPUT_HEADER}" > "${TEMPDIR}/${project}-gerrit-stats.txt"
+    echo "${OUTPUT_HEADER}" > "${TEMPDIR}/${project}-gerrit-stats-all.txt"
     grep -v '^#' ${CONFIGDIR}/${RELEASE} |
         while read project x; do
             DEBUG "Generating gerrit statistics for ${project}"
             python gerritdm -l 20 \
                 < "${TEMPDIR}/${project}-${RELEASE}-reviewers.txt" \
-                > "${TEMPDIR}/${project}-gerrit-stats.txt"
+                >> "${TEMPDIR}/${project}-gerrit-stats.txt"
             python gerritdm -z \
                 < "${TEMPDIR}/${project}-${RELEASE}-reviewers.txt" \
-                > "${TEMPDIR}/${project}-gerrit-stats-all.txt"
+                >> "${TEMPDIR}/${project}-gerrit-stats-all.txt"
         done
 
     DEBUG "Generating aggregate gerrit statistics for all projects"
@@ -177,8 +215,10 @@ if [ "$GERRIT_STATS" = "y" ] ; then
         while read project x; do
             cat "${TEMPDIR}/${project}-${RELEASE}-reviewers.txt" >> "${TEMPDIR}/gerrit-reviewers.txt"
         done
-    python gerritdm -l 20 < "${TEMPDIR}/gerrit-reviewers.txt" > "${TEMPDIR}/gerrit-stats.txt"
-    python gerritdm -z < "${TEMPDIR}/gerrit-reviewers.txt" > "${TEMPDIR}/gerrit-stats-all.txt"
+    echo "${OUTPUT_HEADER}" > "${TEMPDIR}/gerrit-stats.txt"
+    echo "${OUTPUT_HEADER}" > "${TEMPDIR}/gerrit-stats-all.txt"
+    python gerritdm -l 20 < "${TEMPDIR}/gerrit-reviewers.txt" >> "${TEMPDIR}/gerrit-stats.txt"
+    python gerritdm -z < "${TEMPDIR}/gerrit-reviewers.txt" >> "${TEMPDIR}/gerrit-stats-all.txt"
 fi
 
 DEBUG "Cleaning up"