diff --git a/taxcalc/tests/test_cpscsv.py b/taxcalc/tests/test_cpscsv.py
index d1aeb9b1f..3423336d6 100644
--- a/taxcalc/tests/test_cpscsv.py
+++ b/taxcalc/tests/test_cpscsv.py
@@ -51,12 +51,8 @@ def test_agg(tests_path, cps_fullsample):
         txt = expected_file.read()
     expected_results = txt.rstrip('\n\t ') + '\n'  # cleanup end of file txt
     # ensure actual and expected results have no nonsmall differences
-    if sys.version_info.major == 2:
-        small = 0.0  # tighter test for Python 2.7
-    else:
-        small = 0.1  # looser test for Python 3.6
     diffs = nonsmall_diffs(actual_results.splitlines(True),
-                           expected_results.splitlines(True), small)
+                           expected_results.splitlines(True))
     if diffs:
         new_filename = '{}{}'.format(aggres_path[:-10], 'actual.txt')
         with open(new_filename, 'w') as new_file:
diff --git a/taxcalc/tests/test_puf_var_stats.py b/taxcalc/tests/test_puf_var_stats.py
index cc95a3a3d..4b51f3d38 100644
--- a/taxcalc/tests/test_puf_var_stats.py
+++ b/taxcalc/tests/test_puf_var_stats.py
@@ -106,7 +106,7 @@ def calculate_mean_stats(calc, table, year):
     table[str(year)] = means
 
 
-def differences(new_filename, old_filename, stat_kind, small):
+def differences(new_filename, old_filename, stat_kind, small=0.0):
     """
     Return message string if there are differences at least as large as small;
     otherwise (i.e., if there are only small differences) return empty string.
@@ -176,17 +176,7 @@ def test_puf_var_stats(tests_path, puf_fullsample):
     table_corr.to_csv(corr_path, float_format='%8.2f',
                       columns=table_corr.index)
     # compare new and old CSV files for nonsmall differences
-    if sys.version_info.major == 2:
-        # tighter tests for Python 2.7
-        mean_msg = differences(mean_path, mean_path[:-4],
-                               'MEAN', small=0.0)
-        corr_msg = differences(corr_path, corr_path[:-4],
-                               'CORR', small=0.0)
-    else:
-        # looser tests for Python 3.6
-        mean_msg = differences(mean_path, mean_path[:-4],
-                               'MEAN', small=1.0)
-        corr_msg = differences(corr_path, corr_path[:-4],
-                               'CORR', small=0.01)
+    mean_msg = differences(mean_path, mean_path[:-4], 'MEAN')
+    corr_msg = differences(corr_path, corr_path[:-4], 'CORR')
     if mean_msg or corr_msg:
         raise ValueError(mean_msg + corr_msg)
diff --git a/taxcalc/tests/test_pufcsv.py b/taxcalc/tests/test_pufcsv.py
index 3f2c58744..0e10d840d 100644
--- a/taxcalc/tests/test_pufcsv.py
+++ b/taxcalc/tests/test_pufcsv.py
@@ -58,11 +58,7 @@ def test_agg(tests_path, puf_fullsample):
     expected_results = txt.rstrip('\n\t ') + '\n'  # cleanup end of file txt
     expect = expected_results.splitlines(True)
     # ensure actual and expect lines have differences no more than small value
-    if sys.version_info.major == 2:
-        small = 0.0  # tighter test for Python 2.7
-    else:
-        small = 0.1  # looser test for Python 3.6
-    diffs = nonsmall_diffs(actual, expect, small)
+    diffs = nonsmall_diffs(actual, expect)
     if diffs:
         new_filename = '{}{}'.format(aggres_path[:-10], 'actual.txt')
         with open(new_filename, 'w') as new_file:
diff --git a/taxcalc/utils.py b/taxcalc/utils.py
index 0b1440e94..0f0dd80af 100644
--- a/taxcalc/utils.py
+++ b/taxcalc/utils.py
@@ -1600,11 +1600,8 @@ def dec_graph_plot(data,
 def nonsmall_diffs(linelist1, linelist2, small=0.0):
     """
     Return True if line lists differ significantly; otherwise return False.
-    Significant difference means one or more numbers differ (between
-    linelist1 and linelist2) by more than the small amount.
-    NOTE: this function is meant to be used only in the unit tests to handle
-    small differences in floating point values generated by Python 2.7 and 3.6,
-    where a nonzero small amount is used only under Python 3.6.
+    Significant numerical difference means one or more numbers differ (between
+    linelist1 and linelist2) by more than the specified small amount.
     """
     # embedded function used only in nonsmall_diffs function
     def isfloat(value):