diff --git a/scidash/main/settings.py b/scidash/main/settings.py
index 9d0b0b9c..0fd219bc 100644
--- a/scidash/main/settings.py
+++ b/scidash/main/settings.py
@@ -249,3 +249,7 @@
 CELERY_RESULT_BACKEND = 'django-db'
 
 NO_IMPORT_TAG = 'unschedulable'
+
+# SCIDASH
+# Initial search number of quarters to search back in time.
+SCIDASH_INITIAL_SEARCH_QUARTERS = 12
diff --git a/scidash/sciunittests/migrations/0047_auto_20191219_1217.py b/scidash/sciunittests/migrations/0047_auto_20191219_1217.py
new file mode 100644
index 00000000..3d8f5f1b
--- /dev/null
+++ b/scidash/sciunittests/migrations/0047_auto_20191219_1217.py
@@ -0,0 +1,19 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.7 on 2019-12-19 12:17
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('sciunittests', '0046_auto_20190827_0221'),
+    ]
+
+    operations = [
+        migrations.AddIndex(
+            model_name='scoreinstance',
+            index=models.Index(fields=['-timestamp'], name='sciunittest_timesta_aa7614_idx'),
+        ),
+    ]
diff --git a/scidash/sciunittests/models.py b/scidash/sciunittests/models.py
index 2f17f852..f3094fb1 100644
--- a/scidash/sciunittests/models.py
+++ b/scidash/sciunittests/models.py
@@ -243,6 +243,9 @@ def prediction(self):
 
     class Meta:
         ordering = ['-timestamp']
+        indexes = [
+            models.Index(fields=['-timestamp',]),
+        ]
 
     def __str__(self):
         return "Score for {0} in {1} test instance".format(
diff --git a/scidash/sciunittests/views.py b/scidash/sciunittests/views.py
index 99e91b50..e3109d9d 100644
--- a/scidash/sciunittests/views.py
+++ b/scidash/sciunittests/views.py
@@ -9,7 +9,21 @@
 
 class DateRangeView(APIView):
     def get(self, request, *args, **kwargs):
-        three_month_period = datetime.timedelta(3 * 365 / 12)
+        """Returns the initial search period (acceptable_period).
+        for the first N (settings.ACCEPTABLE_SCORE_INSTANCES_AMOUNT) scores.
+
+        Parameters
+        ----------
+        -
+
+        Returns
+        -------
+        JSON object 
+        {
+            "current_date": "<yyyy-mm-ddThh:mi:ss>", 
+            "acceptable_period": "<yyyy-mm-ddThh:mi:ss>"
+        }
+        """
         current_date = datetime.date.today() + datetime.timedelta(days=1)
         current_date_iso = datetime.datetime(
             year=current_date.year,
@@ -17,20 +31,20 @@ def get(self, request, *args, **kwargs):
             day=current_date.day
         )
 
-        acceptable_period = None
-
-        for quarter in range(1, s.SCIDASH_INITIAL_SEARCH_QUARTERS + 1):
-            period = current_date_iso - quarter*three_month_period
-            count = ScoreInstance.objects.filter(
-                timestamp__gte=period, timestamp__lt=current_date_iso
-            ).count()
-
-            if count > s.ACCEPTABLE_SCORE_INSTANCES_AMOUNT:
-                acceptable_period = period
-                break
-
-        if acceptable_period is None:
-            acceptable_period = period
+        scores = ScoreInstance.objects.filter(
+            timestamp__lt=current_date_iso).order_by('-timestamp') \
+            [:s.ACCEPTABLE_SCORE_INSTANCES_AMOUNT]
+        if scores:
+            # found scores, acceptable period is scores last.timestamp
+            # because sorting is DESC timestamp
+            acceptable_period = scores.reverse()[0].timestamp
+        else:
+            # acceptable period defaults to current date - 1 year
+            acceptable_period = datetime.datetime(
+                year=current_date.year-1,
+                month=current_date.month,
+                day=current_date.day
+            )
 
         return Response(
             {