diff --git a/scrunch/datasets.py b/scrunch/datasets.py
index 8ab11750..f4d889ed 100644
--- a/scrunch/datasets.py
+++ b/scrunch/datasets.py
@@ -696,6 +696,17 @@ class DatasetVariablesMixin(Mapping):
     Handles dataset variable iteration in a dict-like way
     """
 
+    create_material_variables = True
+    """New variables created by methods of this class are usually defined by
+    an expression which is evaluated on the server. If create_material_variables
+    is True (the default), such an expression is evaluated eagerly, and its
+    output at that moment is stored as a "material" variable: part of the schema.
+    Changes to any of the input variables will not update the material variable.
+    If False, the expression itself is stored instead and re-evaluated on each
+    read; the resulting "derived" variable is an artifact rather than part of
+    the schema, and will change if any of its inputs change.
+    """
+
     def __getitem__(self, item):
         """
         Returns a Variable() instance, `item` can be either a variable alias,
@@ -744,11 +755,13 @@ def order(self):
             self._order = DatasetVariablesOrder(self._catalog, order)
         return self._order
 
-    def _var_create_reload_return(self, payload):
+    def _var_create_reload_return(self, entity_body):
         """
         helper function for POSTing to variables, reload
         the catalog of variables and return newly created var
         """
+        entity_body.setdefault("derived", not self.create_material_variables)
+        payload = shoji_entity_wrapper(entity_body)
         new_var = self.resource.variables.create(payload)
         # needed to update the variables collection
         self._reload_variables()
@@ -1166,13 +1179,13 @@ def create_fill_values(self, variables, name, alias, description=''):
                 {"map": fill_map}
             ]
         }
-        payload = shoji_entity_wrapper({
+        body = {
             "alias": alias,
             "name": name,
             "description": description,
             "derivation": fill_expr
-        })
-        return self._var_create_reload_return(payload)
+        }
+        return self._var_create_reload_return(body)
 
     def create_single_response(self, categories, name, alias, description='',
         missing=True, notes=''):
@@ -1223,13 +1236,13 @@ def create_single_response(self, categories, name, alias, description='',
 
         expr = dict(function='case', args=args + more_args)
 
-        payload = shoji_entity_wrapper(dict(
+        body = dict(
             alias=alias,
             name=name,
-            expr=expr,
+            derivation=expr,
             description=description,
-            notes=notes))
-        return self._var_create_reload_return(payload)
+            notes=notes)
+        return self._var_create_reload_return(body)
 
     def rollup(self, variable_alias, name, alias, resolution, description='',
         notes=''):
@@ -1249,27 +1262,17 @@ def rollup(self, variable_alias, name, alias, resolution, description='',
         expr = {
             'function': 'rollup',
             'args': [
-                {
-                    'variable': self[variable_alias].url
-                },
-                {
-                    'value': resolution
-                }
+                {'variable': self[variable_alias].url},
+                {'value': resolution}
             ]
         }
-
-        payload = shoji_entity_wrapper(dict(
+        body = dict(
             alias=alias,
             name=name,
-            expr=expr,
+            derivation=expr,
             description=description,
-            notes=notes))
-
-        new_var = self.resource.variables.create(payload)
-        # needed to update the variables collection
-        self._reload_variables()
-        # return the variable instance
-        return self[new_var['body']['alias']]
+            notes=notes)
+        return self._var_create_reload_return(body)
 
     def derive_multiple_response(self, categories, subvariables, name, alias,
         description='', notes='', uniform_basis=False):
@@ -1320,7 +1323,7 @@ def derive_multiple_response(self, categories, subvariables, name, alias,
                 categories=categories
             )
 
-        payload = shoji_entity_wrapper({
+        body = {
             'name': name,
             'alias': alias,
             'description': description,
@@ -1336,8 +1339,8 @@ def derive_multiple_response(self, categories, subvariables, name, alias,
                     ]
                 }]
             }
-        })
-        return self._var_create_reload_return(payload)
+        }
+        return self._var_create_reload_return(body)
 
     def create_multiple_response(self, responses, name, alias, description='',
         notes=''):
@@ -1359,7 +1362,7 @@ def create_multiple_response(self, responses, name, alias, description='',
                 alias='%s_%d' % (alias, resp['id'])
             )
 
-        payload = shoji_entity_wrapper({
+        body = {
             'name': name,
             'alias': alias,
             'description': description,
@@ -1374,8 +1377,8 @@ def create_multiple_response(self, responses, name, alias, description='',
                     ]
                 }]
             }
-        })
-        return self._var_create_reload_return(payload)
+        }
+        return self._var_create_reload_return(body)
 
     def variable_aliases(self, include_subvariables=False):
         existing_aliases = set()
@@ -1445,14 +1448,14 @@ def bind_categorical_array(self, name, alias, subvariables, description='',
                 "subreferences": subreferences
             }
         }
-        payload = shoji_entity_wrapper({
+        body = {
             'name': name,
             'alias': alias,
             'description': description,
             'notes': notes,
             'derivation': expression
-        })
-        return self._var_create_reload_return(payload)
+        }
+        return self._var_create_reload_return(body)
 
     def create_numeric(self, alias, name, derivation, description='', notes=''):
         """
@@ -1464,14 +1467,14 @@ def create_numeric(self, alias, name, derivation, description='', notes=''):
         if not hasattr(self.resource, 'variables'):
             self.resource.refresh()
 
-        payload = shoji_entity_wrapper(dict(
+        body = dict(
             alias=alias,
             name=name,
             derivation=expr,
             description=description,
             notes=notes
-        ))
-        return self._var_create_reload_return(payload)
+        )
+        return self._var_create_reload_return(body)
 
     def create_categorical(self, categories, alias, name, multiple, description='',
         notes='', missing_case=None, uniform_basis=False):
@@ -1690,33 +1693,33 @@ def create_variable(self, var_type, name, alias=None, description='',
             values = [1,4,5,2,1,3,1]
         """
         self._validate_vartypes(var_type, resolution, subvariables, categories)
-        payload = {
+        body = {
             'type': var_type,
             'name': name,
             'description': description,
         }
         if alias:
-            payload['alias'] = alias
+            body['alias'] = alias
         if resolution:
-            payload['resolution'] = resolution
+            body['resolution'] = resolution
         if var_type == 'multiple_response' and categories is None:
-            payload['categories'] = [
+            body['categories'] = [
                 {'name': 'Not selected', 'id': NOT_SELECTED_ID, 'numeric_value': 2, 'missing': False},
                 {'name': 'Selected', 'id': SELECTED_ID, 'numeric_value': 1, 'missing': False, 'selected': True},
             ]
         if categories:
-            payload['categories'] = categories
+            body['categories'] = categories
         if subvariables:
-            payload['subreferences'] = []
+            body['subreferences'] = []
             for item in subvariables:
                 subrefs = {'name': item['name']}
                 if item.get('alias'):
                     subrefs['alias'] = item['alias']
-                payload['subreferences'].append(subrefs)
+                body['subreferences'].append(subrefs)
         if values:
-            payload['values'] = values
+            body['values'] = values
 
-        self._var_create_reload_return(shoji_entity_wrapper(payload))
+        self._var_create_reload_return(body)
 
     def copy_variable(self, variable, name, alias, derived=None, subvariable_codes=None):
         """
@@ -1760,17 +1763,14 @@ def subrefs(_variable, _alias):
             derivation = abs_url(variable.resource.body['derivation'],
                                  variable.resource.self)
             derivation.pop('references', None)
-            payload = shoji_entity_wrapper({
-                'name': name,
-                'alias': alias,
-                'derivation': derivation})
+            body = {'name': name, 'alias': alias, 'derivation': derivation}
 
             if variable.type == _MR_TYPE:
                 # We are re-executing a multiple_response derivation.
                 # We need to update the complex `array` function expression
                 # to contain the new suffixed aliases. Given that the map is
                 # unordered, we have to iterated and find a name match.
-                _ob = payload['body']['derivation']['args'][0]['args'][0]
+                _ob = body['derivation']['args'][0]['args'][0]
                 subvars = _ob['map']
                 subreferences = subrefs(variable, alias)
                 for subref in subreferences:
@@ -1782,15 +1782,9 @@ def subrefs(_variable, _alias):
         else:
             derivation = {
                 'function': 'copy_variable',
-                'args': [{
-                    'variable': variable_resource.self
-                }]
+                'args': [{'variable': variable_resource.self}]
             }
-            payload = shoji_entity_wrapper({
-                'name': name,
-                'alias': alias,
-                'derivation': derivation
-            })
+            body = {'name': name, 'alias': alias, 'derivation': derivation}
 
         if "subvariables" in variable_resource.body:
             api_subreferences = variable_resource.body["subreferences"]
@@ -1814,9 +1808,9 @@ def subrefs(_variable, _alias):
             derivation["references"] = {"subreferences": subreferences}
 
         if derived is False or derived:
-            payload['body']['derived'] = derived
+            body['derived'] = derived
 
-        return self._var_create_reload_return(payload)
+        return self._var_create_reload_return(body)
 
     def combine_categories(self, variable, map, categories, missing=None,
         default=None, name='', alias='', description=''):
@@ -1857,14 +1851,14 @@ def combine_categorical(self, variable, map, categories=None, missing=None,
         # TODO: Implement `default` parameter in Crunch API
         combinations = combinations_from_map(
             map, categories or {}, missing or [])
-        payload = shoji_entity_wrapper({
+        body = {
             'name': name,
             'alias': alias,
             'description': description,
             'derivation': combine_categories_expr(
                 variable.resource.self, combinations)
-        })
-        return self._var_create_reload_return(payload)
+        }
+        return self._var_create_reload_return(body)
 
     def combine_multiple_response(self, variable, map, categories=None, default=None,
         name='', alias='', description=''):
@@ -1889,14 +1883,14 @@ def combine_multiple_response(self, variable, map, categories=None, default=None
         # TODO: Implement `default` parameter in Crunch API
         responses = responses_from_map(variable, map, categories or {}, alias,
                                        parent_alias)
-        payload = shoji_entity_wrapper({
+        body = {
             'name': name,
             'alias': alias,
             'description': description,
             'derivation': combine_responses_expr(
                 variable.resource.self, responses)
-        })
-        return self._var_create_reload_return(payload)
+        }
+        return self._var_create_reload_return(body)
 
     def cast_summary(self, variable, cast_type):
         """
@@ -2778,7 +2772,7 @@ def derive_weight(self, targets, alias, name, description=''):
                     'targets': list(map(list, val.items()))
                 })
 
-        payload = shoji_entity_wrapper({
+        body = {
             'name': name,
             'alias': alias,
             'description': description,
@@ -2786,8 +2780,8 @@ def derive_weight(self, targets, alias, name, description=''):
                 'function': 'rake',
                 'args': _targets
             }
-        })
-        return self._var_create_reload_return(payload)
+        }
+        return self._var_create_reload_return(body)
 
     @property
     def is_view(self):
@@ -3041,7 +3035,7 @@ def edit_categorical(self, categories, rules):
         more_args = process_expr(more_args, self.dataset)
         # epression value building
         expr = dict(function='case', args=args + more_args)
-        payload = shoji_entity_wrapper(dict(expr=expr))
+        payload = shoji_entity_wrapper(dict(derivation=expr))
         # patch the variable with the new payload
         resp = self.resource.patch(payload)
         self._reload_variables()
diff --git a/scrunch/tests/test_datasets.py b/scrunch/tests/test_datasets.py
index 63782aa4..46b7102f 100644
--- a/scrunch/tests/test_datasets.py
+++ b/scrunch/tests/test_datasets.py
@@ -357,6 +357,7 @@ def test_create_numeric(self, mocked_process):
                 'body': {
                     'alias': 'monthly_rent',
                     'name': 'Monthly rent',
+                    "derived": False,
                     'derivation': {
                         'function': '/',
                         'args': [
@@ -398,7 +399,8 @@ def test_rollup(self, mocked_process):
                 'body': {
                     'alias': 'new_rolledup_var',
                     'name': 'new_rolledup_var',
-                    'expr': {
+                    "derived": False,
+                    'derivation': {
                         'function': 'rollup',
                         'args': [
                             {'variable': 'https://test.crunch.io/api/datasets/123456/variables/001/'},
@@ -1483,7 +1485,7 @@ def getitem(key):
         assert not var_tuple.entity.edit.called
 
         # check we call `edit` for derived variables
-        body['derived'] = True
+        body["derived"] = True
         var.integrate()
         var_tuple.entity.edit.assert_called_once_with(derived=False)
 
@@ -2150,6 +2152,7 @@ def test_recode_w_fill(self):
             "element": "shoji:entity",
             "body": {
                 "alias": "filled",
+                "derived": False,
                 "derivation": fill_expr,
                 "name": "Filled var",
                 "description": ""
@@ -2208,6 +2211,7 @@ def test_else_code(self):
             "element": "shoji:entity",
             "body": {
                 "alias": "filled",
+                "derived": False,
                 "derivation": fill_expr,
                 "name": "Filled var",
                 "description": ""
@@ -2266,6 +2270,7 @@ def test_else_var(self):
             "element": "shoji:entity",
             "body": {
                 "alias": "filled",
+                "derived": False,
                 "derivation": fill_expr,
                 "name": "Filled var",
                 "description": ""
@@ -2332,7 +2337,8 @@ def test_recode_single_categorical(self):
                 'notes': '',
                 'alias': 'cat',
                 'name': 'My cat',
-                'expr': {
+                "derived": False,
+                'derivation': {
                     'function': 'case',
                     'args': [{
                         'column': [1, 2, 3, -1],
@@ -2452,6 +2458,7 @@ def test_recode_multiple_response(self):
                 'description': '',
                 'notes': '',
                 'name': 'my mr',
+                "derived": False,
                 'derivation': {
                     'function': 'array',
                     'args': [{
@@ -2625,7 +2632,8 @@ def test_create_categorical_else_case(self):
             "body": {
                 "alias": "agerange",
                 "name": "Age Range",
-                "expr": {
+                "derived": False,
+                "derivation": {
                     "function": "case",
                     "args": [
                         {
@@ -2777,12 +2785,13 @@ def test_create_2_multiple_response_else_case(self):
             }
         }
         ds.resource.variables.create.assert_called_with({
-           "element": "shoji:entity",
+            "element": "shoji:entity",
             "body": {
                 "name": "Age range multi",
                 "alias": "agerange_multi",
                 "description": "",
                 "notes": "",
+                "derived": False,
                 "derivation": {
                     "function": "array",
                     "args": [
@@ -2970,6 +2979,7 @@ def test_create_3_multiple_response_else_case(self):
                 "description": "",
                 "notes": "",
                 "uniform_basis": False,
+                "derived": False,
                 "derivation": {
                     "function": "array",
                     "args": [
@@ -3351,6 +3361,7 @@ def test_create_categorical_missing_case(self):
                 "description": "",
                 "notes": "",
                 "uniform_basis": False,
+                "derived": False,
                 "derivation": {
                     "function": "array",
                     "args": [
@@ -3595,6 +3606,7 @@ def test_derive_multiple_response(self):
                 'description': '',
                 'notes': '',
                 'uniform_basis': False,
+                "derived": False,
                 'derivation': {
                     'function': 'array',
                     'args': [{
@@ -3691,7 +3703,7 @@ def test_base_variable(self):
         var_res.entity.body = {'type': 'numeric'}
 
         def getitem(key):
-            if key == 'derived':
+            if key == "derived":
                 return False
         var_res.__getitem__.side_effect = getitem
         var_res.entity.self = '/variable/url/'
@@ -3703,6 +3715,7 @@ def getitem(key):
             'body': {
                 'alias': 'copy',
                 'name': 'copy',
+                "derived": False,
                 'derivation': {
                     'function': 'copy_variable',
                     'args': [{'variable': '/variable/url/'}]
@@ -3715,7 +3728,7 @@ def test_derived_variable(self):
         var_res = mock.MagicMock()
 
         def getitem(key):
-            if key == 'derived':
+            if key == "derived":
                 return True
         var_res.__getitem__.side_effect = getitem
         var_res.entity.body = {
@@ -3745,6 +3758,7 @@ def getitem(key):
             'body': {
                 'alias': 'copy',
                 'name': 'copy',
+                "derived": False,
                 'derivation': {
                     'function': 'array',
                     'args': [{
@@ -6694,7 +6708,7 @@ class TestHeadingSubtotals(TestDatasetBase):
             'categories': TEST_CATEGORIES(),
             'is_subvar': False,
             'view': {},
-            'derived': False,
+            "derived": False,
         },
     }
 
@@ -6899,14 +6913,11 @@ def test_bind_categorical_array_without_codes(self):
             "references": {"subreferences": subreferences}
         }
         assert args == [{
-            "element": "shoji:entity",
-            "body": {
-                "name": "My Array",
-                "alias": "my_array",
-                "notes": "",
-                "description": "",
-                "derivation": expression,
-            }
+            "name": "My Array",
+            "alias": "my_array",
+            "notes": "",
+            "description": "",
+            "derivation": expression,
         }]
 
     def test_bind_categorical_array_with_codes(self):
@@ -6935,14 +6946,11 @@ def test_bind_categorical_array_with_codes(self):
             "references": {"subreferences": subreferences}
         }
         assert args == [{
-            "element": "shoji:entity",
-            "body": {
-                "name": "My Array",
-                "alias": "my_array",
-                "notes": "",
-                "description": "",
-                "derivation": expression,
-            }
+            "name": "My Array",
+            "alias": "my_array",
+            "notes": "",
+            "description": "",
+            "derivation": expression,
         }]
 
     def test_copy_variable_no_codes(self):
@@ -6998,12 +7006,9 @@ def test_copy_variable_no_codes(self):
             "references": {"subreferences": subreferences}
         }
         assert args == [{
-            "element": "shoji:entity",
-            "body": {
-                "name": "copied",
-                "alias": "copied",
-                "derivation": expression,
-            }
+            "name": "copied",
+            "alias": "copied",
+            "derivation": expression,
         }]
 
     def test_copy_variable_with_codes(self):
@@ -7061,11 +7066,7 @@ def test_copy_variable_with_codes(self):
             "references": {"subreferences": subreferences}
         }
         assert args == [{
-            "element": "shoji:entity",
-            "body": {
-                "name": "copied",
-                "alias": "copied",
-                "derivation": expression,
-            }
+            "name": "copied",
+            "alias": "copied",
+            "derivation": expression,
         }]
-
diff --git a/scrunch/tests/test_recodes.py b/scrunch/tests/test_recodes.py
index e1189d99..acf3ce92 100644
--- a/scrunch/tests/test_recodes.py
+++ b/scrunch/tests/test_recodes.py
@@ -55,6 +55,7 @@ def mr_in(mr_self, mr_alias, groups, parent_subvariables):
     'element': 'shoji:entity',
     'body': {
         'alias': 'alias',
+        "derived": False,
         'derivation': {
             'function': 'combine_categories',
             'args': [
@@ -76,6 +77,7 @@ def mr_in(mr_self, mr_alias, groups, parent_subvariables):
         'name': 'name',
         'description': '',
         'alias': 'alias',
+        "derived": False,
         'derivation': {
             'function': 'combine_responses',
             'args': [
@@ -351,7 +353,8 @@ def test_recode_categoricals(self, get_dataset_mock):
                 'alias': 'sexuality2',
                 'description': '',
                 'notes': '',
-                'expr': {
+                "derived": False,
+                'derivation': {
                     'function': 'case',
                     'args': [{
                         'column': [1, 2, -1],
@@ -491,6 +494,7 @@ def test_recode_multiple_responses(self, get_dataset_mock):
                 'description': '',
                 'notes': '',
                 'alias': 'Q1_recoded',
+                "derived": False,
                 'derivation': {
                     'function': 'array',
                     'args': [{