diff --git a/src/resp_ode/config.py b/src/resp_ode/config.py
index 9950eac..c52391e 100644
--- a/src/resp_ode/config.py
+++ b/src/resp_ode/config.py
@@ -107,14 +107,31 @@ def assert_valid_configuration(self):
                 validator_funcs = make_list_if_not(validator_funcs)
                 vals = [getattr(self, k) for k in key]
                 # val_func() throws assert errors if incongruence arrises
-                [
-                    (
-                        val_func(key[0], vals[0])
-                        if len(key) == 1  # convert back to floats if needed
-                        else val_func(key, vals)
-                    )
-                    for val_func in validator_funcs
-                ]
+                try:
+                    [
+                        (
+                            val_func(key[0], vals[0])
+                            if len(key)
+                            == 1  # convert back to floats if needed
+                            else val_func(key, vals)
+                        )
+                        for val_func in validator_funcs
+                    ]
+                except Exception as e:
+                    if len(key) > 1:
+                        err_text = """There was an issue validating your Config object.
+                        The error was caused by the intersection of the following parameters: %s.
+                        %s""" % (
+                            key,
+                            e,
+                        )
+                    else:
+                        err_text = """The following error occured while validating the %s
+                        parameter in your configuration file: %s""" % (
+                            key[0],
+                            e,
+                        )
+                    raise ConfigValidationError(err_text)
 
 
 def make_list_if_not(obj):
@@ -291,6 +308,16 @@ def test_positive(key, value):
         )
 
 
+def test_enum_len(key, enum, expected_len):
+    assert (
+        len(enum) == expected_len
+    ), "Expected %s to have %s entries, got %s" % (
+        key,
+        expected_len,
+        len(enum),
+    )
+
+
 def test_not_negative(key, value):
     """
     checks if a value is not negative.
@@ -654,6 +681,13 @@ class is accepted to modify/create the downstream parameters.
             key, [(vals[0], 2 ** vals[0]), vals[1]]
         ),
     },
+    {
+        "name": ["NUM_STRAINS", "STRAIN_IDX"],
+        # check that len(STRAIN_IDX)==NUM_STRAINS
+        "validate": lambda keys, vals: test_enum_len(
+            keys[1], vals[1], vals[0]
+        ),
+    },
     {
         "name": "MAX_VACCINATION_COUNT",
         "validate": test_not_negative,
@@ -852,4 +886,14 @@ class is accepted to modify/create the downstream parameters.
 
 
 class ConfigParserError(Exception):
+    """A basic class meant to denote when the Config
+    class is having an issue parsing a configuration file"""
+
+    pass
+
+
+class ConfigValidationError(Exception):
+    """A basic class meant to denote when the Config
+    class is having an issue validating a configuration file"""
+
     pass
diff --git a/tests/test_config.py b/tests/test_config.py
index 6ab94c7..7134f5f 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -7,7 +7,7 @@
 import numpyro.distributions as dist
 import pytest
 
-from resp_ode.config import Config, ConfigParserError
+from resp_ode.config import Config, ConfigParserError, ConfigValidationError
 
 GLOBAL_TEST_CONFIG = "tests/test_config_global.json"
 PATH_VARIABLES = [
@@ -38,7 +38,7 @@ def test_valid_path_variables():
 def test_invalid_type_path_variables():
     for path_var in PATH_VARIABLES:
         example_input_json = """{"%s":%d}""" % (path_var, 10)
-        with pytest.raises(AssertionError):
+        with pytest.raises(ConfigValidationError):
             Config(example_input_json)
     for path_var in PATH_VARIABLES:
         example_input_json = """{"%s":"%s"}""" % (
@@ -46,55 +46,55 @@ def test_invalid_type_path_variables():
             "some_random_incorrect_path.json",
         )
         print(example_input_json)
-        with pytest.raises(AssertionError):
+        with pytest.raises(ConfigValidationError):
             Config(example_input_json)
 
 
 def test_non_ascending_age_limits():
     input_json = """{"AGE_LIMITS": [10, 1, 50, 60]}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_out_of_bounds_age_limits():
     input_json = """{"AGE_LIMITS": [0, 18, 50, 64, 95]}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_negative_age_limits():
     input_json = """{"AGE_LIMITS": [-10, 18, 50, 64]}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_float_ages():
     input_json = """{"AGE_LIMITS": [0, 5.5, 18, 50, 64]}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_invalid_seasonality_amplitude_type():
     input_json = """{"SEASONALITY_AMPLITUDE": [0]}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_invalid_seasonality_amplitude_val():
     input_json = """{"SEASONALITY_AMPLITUDE": 4.0}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_invalid_vax_age_coefs_type():
     input_json = """{"AGE_DOSE_SPECIFIC_VAX_COEF": "blah"}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_invalid_vax_path():
     input_json = """{"VACCINATION_MODEL_DATA": "blah"}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -105,7 +105,7 @@ def test_invalid_vax_age_coefs_vals():
                     "NUM_AGE_GROUPS":3,
                     "MAX_VACCINATION_COUNT": 2
                         }"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -123,7 +123,7 @@ def test_valid_vax_age_coefs():
 
 def test_invalid_seasonality_amplitude_val_negative():
     input_json = """{"SEASONALITY_AMPLITUDE": -4.0}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -135,7 +135,7 @@ def test_invalid_seasonality_amplitude_dist():
             "loc": 0
         }
     }}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -157,19 +157,19 @@ def test_valid_seasonality_amplitude_dist():
 
 def test_invalid_seasonality_second_wave_type():
     input_json = """{"SEASONALITY_SECOND_WAVE": [0]}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_invalid_seasonality_second_wave_val():
     input_json = """{"SEASONALITY_SECOND_WAVE": 1.5}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_invalid_seasonality_second_wave_val_negative():
     input_json = """{"SEASONALITY_SECOND_WAVE": -1.5}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -181,7 +181,7 @@ def test_invalid_seasonalit_second_wave_dist():
             "loc": 0
         }
     }}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -203,19 +203,19 @@ def test_valid_seasonality_second_wave_dist():
 
 def test_invalid_seasonality_shift_type():
     input_json = """{"SEASONALITY_SHIFT": [0]}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_invalid_seasonality_shift_val():
     input_json = """{"SEASONALITY_SHIFT": 183}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_invalid_seasonality_shift_val_negative():
     input_json = """{"SEASONALITY_SHIFT": -183}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -227,7 +227,7 @@ def test_invalid_seasonalit_shift_dist():
             "loc": 0
         }
     }}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -254,13 +254,13 @@ def test_valid_seasonality_shift_dist():
 
 def test_invalid_introduction_perc_type():
     input_json = """{"INTRODUCTION_PCTS": 0.1}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_invalid_introduction_perc_val():
     input_json = """{"INTRODUCTION_PCTS":[-1]}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -271,13 +271,13 @@ def test_valid_introduction_perc():
 
 def test_invalid_introduction_times_type():
     input_json = """{"INTRODUCTION_TIMES": 0}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_invalid_introduction_times_val():
     input_json = """{"INTRODUCTION_TIMES": [-1]}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -288,13 +288,13 @@ def test_valid_introduction_times_val():
 
 def test_invalid_introduction_scale_type():
     input_json = """{"INTRODUCTION_SCALES": 5}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_invalid_introduction_scale_val():
     input_json = """{"INTRODUCTION_SCALES": [-1]}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -310,13 +310,13 @@ def test_valid_age_limits():
 
 def test_negative_population_size():
     input_json = """{"POP_SIZE": -1}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_str_population_size():
     input_json = """{"POP_SIZE": "5"}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -327,31 +327,31 @@ def test_valid_population_size():
 
 def test_negative_initial_infections():
     input_json = """{"INITIAL_INFECTIONS": -5}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_negative_initial_infections_scale():
     input_json = """{"INITIAL_INFECTIONS_SCALE": -1.2}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_negative_tree_depth():
     input_json = """{"MAX_TREE_DEPTH": -1}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_zero_tree_depth():
     input_json = """{"MAX_TREE_DEPTH": 0}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_float_tree_depth():
     input_json = """{"MAX_TREE_DEPTH": 1.2}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -362,7 +362,7 @@ def test_valid_tree_depth():
 
 def test_str_initial_infections():
     input_json = """{"INITIAL_INFECTIONS": "5"}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -378,10 +378,28 @@ def test_valid_initial_infections_float():
 
 def test_init_infections_greater_than_pop_size():
     input_json = """{"POP_SIZE": 1, "INITIAL_INFECTIONS": 5}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
+def test_strain_idx_shorter_than_num_strains():
+    input_json = """{"NUM_STRAINS": 3, "STRAIN_IDX": ["x", "y"]}"""
+    with pytest.raises(ConfigValidationError):
+        Config(input_json)
+
+
+def test_strain_idx_longer_than_num_strains():
+    input_json = """{"NUM_STRAINS": 2, "STRAIN_IDX": ["x", "y", "z"]}"""
+    with pytest.raises(ConfigValidationError):
+        Config(input_json)
+
+
+def test_strain_idx_equal_to_num_strains():
+    input_json = """{"NUM_STRAINS": 2, "STRAIN_IDX": ["x", "y"]}"""
+    c = Config(input_json)
+    assert c.NUM_STRAINS == 2 and len(c.STRAIN_IDX) == 2
+
+
 def test_init_infections_less_than_pop_size():
     input_json = """{"POP_SIZE": 5, "INITIAL_INFECTIONS": 1}"""
     c = Config(input_json)
@@ -396,13 +414,13 @@ def test_valid_infectious_period():
 
 def test_negative_infectious_period():
     input_json = """{"INFECTIOUS_PERIOD": -5}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
 def test_invalid_support_infectious_period():
     input_json = """{"INFECTIOUS_PERIOD": {"distribution": "Normal", "params": {"loc": 0, "scale":1}}}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -414,7 +432,7 @@ def test_valid_support_infectious_period():
 
 def test_invalid_step_size():
     input_json = """{"CONSTANT_STEP_SIZE": -1.0}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)
 
 
@@ -515,7 +533,7 @@ def test_invalid_support_nested_distribution_infectious_period():
                 }
             }
         }}"""
-    with pytest.raises(AssertionError):
+    with pytest.raises(ConfigValidationError):
         Config(input_json)