diff --git a/.github/workflows/schemacode_ci.yml b/.github/workflows/schemacode_ci.yml
index 46c437826c..db6e77700a 100644
--- a/.github/workflows/schemacode_ci.yml
+++ b/.github/workflows/schemacode_ci.yml
@@ -33,7 +33,7 @@ jobs:
       - name: "Install build dependencies"
         run: pip install --upgrade build twine
       - name: "Install test dependencies on tag"
-        run: pip install --upgrade tools/schemacode[tests]
+        run: pip install --upgrade tools/schemacode[all]
         if: ${{ startsWith(github.ref, 'refs/tags/schema-') }}
       - name: "Build archive on tag"
         run: pytest tools/schemacode/bidsschematools -k make_archive
diff --git a/src/appendices/qmri.md b/src/appendices/qmri.md
index d0991be72e..d5367cfcdd 100644
--- a/src/appendices/qmri.md
+++ b/src/appendices/qmri.md
@@ -133,10 +133,13 @@ A guide for using macros can be found at
 
 Please visit the [file collections appendix](./file-collections.md#magnetic-resonance-imaging) to see the list of currently supported qMRI applications.
 
-### Quantitative maps are derivatives
+### Outputs are quantitative maps
 
-Regardless of how they are obtained (pre- or post-generated), qMRI maps are stored in the `derivatives` directory.
-For example a `T1map` can be generated from an `MP2RAGE` file collection using either options.
+qMRI maps are stored differently depending on the process that generated them.
+Pre-generated qMRI maps MAY be stored as part of a raw BIDS dataset,
+whereas they MUST be stored in a derivative BIDS dataset if they were post-generated.
+
+See the example below of a `T1map` generated from an `MP2RAGE` file collection using either option.
 
 If the map is post-generated:
 
@@ -151,15 +154,25 @@ A guide for using macros can be found at
             "qMRI-software-name": {
                 "sub-01": {
                     "anat": {
-                        "sub-01_T1map.nii.gz": "",
+                        "sub-01_T1map.nii.gz": " # --> T1 map in a derivative dataset",
                         "sub-01_T1map.json": "",
-                        "sub-01_UNIT1.nii.gz": "",
+                        "sub-01_UNIT1.nii.gz": " # --> UNI T1 in a derivative dataset",
                         "sub-01_UNIT1.json": "",
-                        },
                     },
                 },
             },
         },
+        "sub-01": {
+            "anat": {
+                "sub-01_inv-1_part-mag_MP2RAGE.nii.gz":"",
+                "sub-01_inv-1_part-phase_MP2RAGE.nii.gz":"",
+                "sub-01_inv-1_MP2RAGE.json":"",
+                "sub-01_inv-2_part-mag_MP2RAGE.nii.gz":"",
+                "sub-01_inv-2_part-phase_MP2RAGE.nii.gz":"",
+                "sub-01_inv-2_MP2RAGE.json":"",
+            },
+        },
+    },
    }
 ) }}
 
@@ -172,25 +185,30 @@ A guide for using macros can be found at
 {{ MACROS___make_filetree_example(
    {
     "ds-example": {
-        "derivatives": {
-            "Siemens": {
-                "sub-01": {
-                    "anat": {
-                        "sub-01_T1map.nii.gz": "",
-                        "sub-01_T1map.json": "",
-                        "sub-01_UNIT1.nii.gz": "",
-                        "sub-01_UNIT1.json": "",
-                        },
-                    },
-                },
+        "sub-01": {
+            "anat": {
+                "sub-01_inv-1_part-mag_MP2RAGE.nii.gz":"",
+                "sub-01_inv-1_part-phase_MP2RAGE.nii.gz":"",
+                "sub-01_inv-1_MP2RAGE.json":"",
+                "sub-01_inv-2_part-mag_MP2RAGE.nii.gz":"",
+                "sub-01_inv-2_part-phase_MP2RAGE.nii.gz":"",
+                "sub-01_inv-2_MP2RAGE.json":"",
+                "sub-01_T1map.nii.gz": " # --> T1 map in a raw dataset",
+                "sub-01_T1map.json": "",
+                "sub-01_UNIT1.nii.gz": " # --> UNI T1 in a raw dataset",
+                "sub-01_UNIT1.json": "",
             },
         },
+    }
    }
 ) }}
 
-Note: Even though the process from which pre-generated qMRI maps are obtained (vendor pipelines) is not known,
-vendors generally allow exporting of the corresponding input data.
-It is RECOMMENDED to share them along with the vendor outputs, whenever possible for a qMRI method supported by BIDS.
+!!! note "Sharing of vendor outputs"
+
+    Even though the process from which pre-generated qMRI maps are obtained (vendor pipelines) is not known,
+    vendors generally allow exporting of the corresponding input data.
+    It is RECOMMENDED to share them along with the vendor outputs,
+    whenever possible for a qMRI method supported by BIDS.
 
 ### Example datasets
 
@@ -326,7 +344,7 @@ A guide for using macros can be found at
 
 `dataset_description.json`:
 
-```text
+```json
 {
   "Name": "qMRLab Outputs",
   "BIDSVersion": "1.5.0",
@@ -526,12 +544,13 @@ as an input to offline calculation of a `T1map` using a dictionary lookup approa
 provided by the stock sequence. Instead, the `magnitude` and `phase` images are exported. Please
 see the relevant discussion at [qMRLab issue #255](https://github.com/qMRLab/qMRLab/issues/255).
 
-Therefore, the `UNIT1` image provided by the scanner is RECOMMENDED to be stored under the `anat`
-raw dataset directory along with the `MP2RAGE` file collection and to be used as the primary input
-for quantifying a `T1map`.
+Therefore, the `UNIT1` image provided by the scanner
+SHOULD be stored under the `anat` in a raw BIDS dataset
+along with the `MP2RAGE` file collection
+and to be used as the primary input for quantifying a `T1map`.
 
-If an additional `UNIT1` image is calculated offline, then the output is to be stored in the
-`derivatives` directory with necessary provenance information.
+If an additional `UNIT1` image is calculated offline,
+then the output MUST be stored in a derivative BIDS dataset with necessary provenance information.
 
 ##### `NumberShots` metadata field
 
diff --git a/src/modality-specific-files/magnetic-resonance-imaging-data.md b/src/modality-specific-files/magnetic-resonance-imaging-data.md
index fc1424d102..9a6fd23927 100644
--- a/src/modality-specific-files/magnetic-resonance-imaging-data.md
+++ b/src/modality-specific-files/magnetic-resonance-imaging-data.md
@@ -166,7 +166,7 @@ A guide for using macros can be found at
    ])
 }}
 
-#### Tissue description
+### Tissue description
 
 <!-- This block generates a metadata table.
 These tables are defined in
@@ -178,6 +178,31 @@ A guide for using macros can be found at
 -->
 {{ MACROS___make_sidecar_table("mri.MRISample") }}
 
+### Deidentification information
+
+Describes the mechanism or method used to modify or remove metadata
+and/or pixel data to protect the patient or participant's identity.
+
+<!-- This block generates a metadata table.
+These tables are defined in
+  src/schema/rules/sidecars
+The definitions of the fields specified in these tables may be found in
+  src/schema/objects/metadata.yaml
+A guide for using macros can be found at
+ https://github.com/bids-standard/bids-specification/blob/master/macros_doc.md
+-->
+{{ MACROS___make_sidecar_table("mri.DeidentificationMethod") }}
+
+Each object in the `DeidentificationMethodCodeSequence` array includes the following RECOMMENDED keys:
+
+<!-- This block generates a table describing subfields within a metadata field.
+The definitions of these fields can be found in
+  src/schema/objects/metadata.yaml
+and a guide for using macros can be found at
+ https://github.com/bids-standard/bids-specification/blob/master/macros_doc.md
+-->
+{{ MACROS___make_subobject_table("metadata.DeidentificationMethodCodeSequence.items") }}
+
 ## Anatomy imaging data
 
 Anatomy MRI sequences measure static, structural features of the brain.
diff --git a/src/modality-specific-files/magnetic-resonance-spectroscopy.md b/src/modality-specific-files/magnetic-resonance-spectroscopy.md
index 22ec6540e0..1b9b26b22b 100644
--- a/src/modality-specific-files/magnetic-resonance-spectroscopy.md
+++ b/src/modality-specific-files/magnetic-resonance-spectroscopy.md
@@ -8,9 +8,8 @@ context of the academic literature.
 
 !!! example "Example datasets"
 
-    Several [example MRS datasets](https://github.com/bids-standard/bids-examples/pull/425) have
-    been formatted using this specification and can be used for practical guidance when curating a new
-    dataset.
+    Several [example MRS datasets](https://github.com/bids-standard/bids-examples?tab=readme-ov-file#mrs) have
+    been formatted using this specification and can be used for practical guidance when curating a new dataset.
 
 ## MRS data
 
@@ -50,11 +49,13 @@ The `*.sdat` file contains either each coil-combined transient stored separately
 or all transients summed into a signal average.
 The `*.spar` file is a plaintext file describing acquisition parameters.
 It is also possible to export raw data as `*.data`/`*.list` or DICOM files.
-Siemens scanners allow data export in four formats: i) a proprietary DICOM-structured file known as IMA (`*.ima`);
-ii) a conventional DICOM MR Spectroscopy Storage format (`*.dcm`); iii) RDA (`*.rda`),
-a proprietary file format with a text-formatted header followed by the binary data points;
-and iv) TWIX (`*.dat`), a proprietary file format designed for storing unreconstructed, unprocessed MRS data
-from each individual coil element.
+Siemens scanners allow data export in four formats:
+
+1.  a proprietary DICOM-structured file known as IMA (`*.ima`);
+1.  a conventional DICOM MR Spectroscopy Storage format (`*.dcm`);
+1.  RDA (`*.rda`), a proprietary file format with a text-formatted header followed by the binary data points;
+1.  TWIX (`*.dat`), a proprietary file format designed for storing unreconstructed, unprocessed MRS data from each individual coil element.
+
 The IMA, DICOM MRS, and RDA formats are typically used to export reconstructed and processed data;
 however, the sequence designer may choose to also allow the export of un-averaged transients
 or data from individual coil elements.
@@ -153,6 +154,18 @@ A guide for using macros can be found at
 -->
 {{ MACROS___make_sidecar_table("mrs.MRSScannerHardware") }}
 
+#### Institution information
+
+<!-- This block generates a metadata table.
+These tables are defined in
+  src/schema/rules/sidecars
+The definitions of the fields specified in these tables may be found in
+  src/schema/objects/metadata.yaml
+A guide for using macros can be found at
+ https://github.com/bids-standard/bids-specification/blob/master/macros_doc.md
+-->
+{{ MACROS___make_sidecar_table("mrs.MRSInstitutionInformation") }}
+
 #### Sequence specifics
 
 <!-- This block generates a metadata table.
diff --git a/src/modality-specific-files/positron-emission-tomography.md b/src/modality-specific-files/positron-emission-tomography.md
index f15f3fad40..856789a887 100644
--- a/src/modality-specific-files/positron-emission-tomography.md
+++ b/src/modality-specific-files/positron-emission-tomography.md
@@ -230,6 +230,31 @@ A guide for using macros can be found at
 -->
 {{ MACROS___make_sidecar_table("pet.PETSample") }}
 
+#### Deidentification information
+
+Describes the mechanism or method used to modify or remove metadata
+and/or pixel data to protect the patient or participant's identity.
+
+<!-- This block generates a metadata table.
+These tables are defined in
+  src/schema/rules/sidecars
+The definitions of the fields specified in these tables may be found in
+  src/schema/objects/metadata.yaml
+A guide for using macros can be found at
+ https://github.com/bids-standard/bids-specification/blob/master/macros_doc.md
+-->
+{{ MACROS___make_sidecar_table("mri.DeidentificationMethod") }}
+
+Each object in the `DeidentificationMethodCodeSequence` array includes the following RECOMMENDED keys:
+
+<!-- This block generates a table describing subfields within a metadata field.
+The definitions of these fields can be found in
+  src/schema/objects/metadata.yaml
+and a guide for using macros can be found at
+ https://github.com/bids-standard/bids-specification/blob/master/macros_doc.md
+-->
+{{ MACROS___make_subobject_table("metadata.DeidentificationMethodCodeSequence.items") }}
+
 #### Task
 
 If the OPTIONAL [`task-<label>`](../appendices/entities.md#task) is used,
diff --git a/src/schema/SCHEMA_VERSION b/src/schema/SCHEMA_VERSION
index 72ab694d37..008d412103 100644
--- a/src/schema/SCHEMA_VERSION
+++ b/src/schema/SCHEMA_VERSION
@@ -1 +1 @@
-0.11.1-dev
+0.11.2-dev
diff --git a/src/schema/objects/metadata.yaml b/src/schema/objects/metadata.yaml
index d99fcc599b..f2c3b25c74 100644
--- a/src/schema/objects/metadata.yaml
+++ b/src/schema/objects/metadata.yaml
@@ -591,6 +591,55 @@ DecayCorrectionFactor:
   type: array
   items:
     type: number
+DeidentificationMethod:
+  name: DeidentificationMethod
+  display_name: Deidentification Method
+  description: |
+    A description of the mechanism or method used to remove the Patient's identity.
+    Corresponds to DICOM Tag 0012, 0063 `De-identification Method`.
+  type: array
+  items:
+    type: string
+DeidentificationMethodCodeSequence:
+  name: DeidentificationMethodCodeSequence
+  display_name: Deidentification Method Code Sequence
+  description: |
+    A sequence of code objects describing the mechanism or method use to remove the Patient's identity.
+    Corresponds to DICOM Tag 0012, 0064 `De-identification Method Code Sequence`.
+  type: array
+  items:
+    type: object
+    recommended_fields:
+      - CodeValue
+      - CodeMeaning
+      - CodingSchemeDesignator
+      - CodingSchemeVersion
+    properties:
+      CodeValue:
+        name: CodeValue
+        type: string
+        description: |
+          An identifier that is unambiguous within the Coding Scheme
+          denoted by Coding Scheme Designator and Coding Scheme Version.
+          Corresponds to DICOM Tag 0008, 0100 `Code Value`.
+      CodeMeaning:
+        name: CodeMeaning
+        type: string
+        description: |
+          Text that has meaning to a human and conveys the meaning of the term
+          Corresponds to DICOM Tag 0008, 0104 `Code Meaning`.
+      CodingSchemeDesignator:
+        name: CodingSchemeDesignator
+        type: string
+        description: |
+          The identifier of the coding scheme in which the coded entry is defined.
+          Corresponds to DICOM Tag 0008, 0102 `Coding Scheme Designator`.
+      CodingSchemeVersion:
+        name: CodingSchemeVersion
+        type: string
+        description: |
+          An identifier of the version of the coding scheme if necessary to resolve ambiguity.
+          Corresponds to DICOM Tag 0008, 0103 `Coding Scheme Version`.
 DelayAfterTrigger:
   name: DelayAfterTrigger
   display_name: Delay After Trigger
diff --git a/src/schema/objects/suffixes.yaml b/src/schema/objects/suffixes.yaml
index 1e2825ced2..183a50b75a 100644
--- a/src/schema/objects/suffixes.yaml
+++ b/src/schema/objects/suffixes.yaml
@@ -6,11 +6,6 @@ TwoPE:
   display_name: 2-photon excitation microscopy
   description: |
     2-photon excitation microscopy imaging data
-ADC:
-  value: ADC
-  display_name: Apparent diffusion coefficient (ADC)
-  description:
-    Apparent diffusion coefficient (ADC) map
 BF:
   value: BF
   display_name: Bright-field microscopy
diff --git a/src/schema/rules/checks/asl.yaml b/src/schema/rules/checks/asl.yaml
index 1b42593212..2ae11ebeb0 100644
--- a/src/schema/rules/checks/asl.yaml
+++ b/src/schema/rules/checks/asl.yaml
@@ -196,21 +196,21 @@ ASLBackgroundSuppressionNumberPulses:
     - length(sidecar.BackgroundSuppressionPulseTime) == sidecar.BackgroundSuppressionNumberPulses
 
 # 181
-ASLTotalAcquiredVolumesASLContextLength:
+ASLTotalAcquiredPairsASLContextLength:
   issue:
     code: TOTAL_ACQUIRED_VOLUMES_NOT_CONSISTENT
     message: |
-      The number of values for 'TotalAcquiredVolumes' for this file does not match number of
+      The number of values for 'TotalAcquiredPairs' for this file does not match number of
       volumes in the associated 'aslcontext.tsv'.
-      'TotalAcquiredVolumes' is the original number of 3D volumes acquired for each volume defined in the
+      'TotalAcquiredPairs' is the original number of 3D volumes acquired for each volume defined in the
       associated 'aslcontext.tsv'.
     level: warning
   selectors:
     - suffix == "asl"
     - type(associations.aslcontext) != "null"
-    - '"TotalAcquiredVolumes" in sidecar'
+    - '"TotalAcquiredPairs" in sidecar'
   checks:
-    - aslcontext.n_rows == sidecar.TotalAcquiredVolumes
+    - aslcontext.n_rows == sidecar.TotalAcquiredPairs
 
 # 184
 PostLabelingDelayGreater:
diff --git a/src/schema/rules/checks/micr.yaml b/src/schema/rules/checks/micr.yaml
index bf2f4c55c3..431113cc10 100644
--- a/src/schema/rules/checks/micr.yaml
+++ b/src/schema/rules/checks/micr.yaml
@@ -10,17 +10,34 @@ PixelSizeInconsistent:
   selectors:
     - ome != null
     - sidecar.PixelSize != null
-    - sidecar.PixelSizeUnit != null
+    - sidecar.PixelSizeUnits != null
   checks:
+    # Note that OME-XML uses µm for microns and BIDS uses um
+    # Accept an error up to .001 of the BIDS unit, to account for floating point error
     - |
-      ome.PhysicalSizeX * 10 ** (-3 * index(["mm", "um", "nm"], ome.PhysicalSizeXUnit))
-      == sidecar.PixelSize[0] * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnit))
+      ome.PhysicalSizeX * 10 ** (-3 * index(["mm", "µm", "nm"], ome.PhysicalSizeXUnit))
+      - sidecar.PixelSize[0] * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnits))
+      < 0.001 * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnits))
     - |
-      ome.PhysicalSizeY * 10 ** (-3 * index(["mm", "um", "nm"], ome.PhysicalSizeYUnit))
-      == sidecar.PixelSize[1] * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnit))
+      sidecar.PixelSize[0] * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnits))
+      - ome.PhysicalSizeX * 10 ** (-3 * index(["mm", "µm", "nm"], ome.PhysicalSizeXUnit))
+      < 0.001 * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnits))
     - |
-      ome.PhysicalSizeZ * 10 ** (-3 * index(["mm", "um", "nm"], ome.PhysicalSizeZUnit))
-      == sidecar.PixelSize[2] * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnit))
+      ome.PhysicalSizeY * 10 ** (-3 * index(["mm", "µm", "nm"], ome.PhysicalSizeYUnit))
+      - sidecar.PixelSize[1] * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnits))
+      < 0.001 * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnits))
+    - |
+      sidecar.PixelSize[1] * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnits))
+      - ome.PhysicalSizeY * 10 ** (-3 * index(["mm", "µm", "nm"], ome.PhysicalSizeYUnit))
+      < 0.001 * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnits))
+    - |
+      ome.PhysicalSizeZ * 10 ** (-3 * index(["mm", "µm", "nm"], ome.PhysicalSizeZUnit))
+      - sidecar.PixelSize[2] * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnits))
+      < 0.001 * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnits))
+    - |
+      sidecar.PixelSize[2] * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnits))
+      - ome.PhysicalSizeZ * 10 ** (-3 * index(["mm", "µm", "nm"], ome.PhysicalSizeZUnit))
+      < 0.001 * 10 ** (-3 * index(["mm", "um", "nm"], sidecar.PixelSizeUnits))
 
 # 227
 InconsistentTiffExtension:
diff --git a/src/schema/rules/checks/mri.yaml b/src/schema/rules/checks/mri.yaml
index e2efc0216d..91a1520179 100644
--- a/src/schema/rules/checks/mri.yaml
+++ b/src/schema/rules/checks/mri.yaml
@@ -109,9 +109,9 @@ BolusCutOffDelayTimeNotMonotonicallyIncreasing:
     level: error
   selectors:
     - modality == "mri"
-    - sidecar.BolusCutoffDelayTime != null
+    - sidecar.BolusCutOffDelayTime != null
   checks:
-    - allequal(sorted(sidecar.BolusCutoffDelayTime), sidecar.BolusCutoffDelayTime)
+    - allequal(sorted(sidecar.BolusCutOffDelayTime), sidecar.BolusCutOffDelayTime)
 
 # 201
 RepetitionTimePreparationNotConsistent:
diff --git a/src/schema/rules/sidecars/mri.yaml b/src/schema/rules/sidecars/mri.yaml
index d57a053bec..1edcdb157b 100644
--- a/src/schema/rules/sidecars/mri.yaml
+++ b/src/schema/rules/sidecars/mri.yaml
@@ -373,3 +373,14 @@ MRIInstitutionInformation:
     InstitutionalDepartmentName:
       level: recommended
       description_addendum: Corresponds to DICOM Tag 0008, 1040 `Institutional Department Name`.
+
+DeidentificationMethod:
+  selectors:
+    - intersects([modality], ["mri", "pet"])
+  fields:
+    DeidentificationMethod:
+      level: optional
+      description_addendum: Corresponds to DICOM Tag 0012, 0063 `De-identification Method`.
+    DeidentificationMethodCodeSequence:
+      level: optional
+      description_addendum: Corresponds to DICOM Tag 0012, 0064 `De-identification Method Code Sequence`.
diff --git a/src/schema/rules/sidecars/mrs.yaml b/src/schema/rules/sidecars/mrs.yaml
index 28796eb5e4..67d8d5e13b 100644
--- a/src/schema/rules/sidecars/mrs.yaml
+++ b/src/schema/rules/sidecars/mrs.yaml
@@ -6,14 +6,20 @@
 
 ---
 # MRS Common metadata fields
-MRSScannerHardware:
+MRSInstitutionInformation:
   selectors:
     - modality == "mrs"
     - match(extension, "^\.nii(\.gz)?$")
   fields:
-    InstitutionName: recommended
     InstitutionAddress: recommended
+    InstitutionName: recommended
     InstitutionalDepartmentName: recommended
+
+MRSScannerHardware:
+  selectors:
+    - modality == "mrs"
+    - match(extension, "^\.nii(\.gz)?$")
+  fields:
     Manufacturer: recommended
     ManufacturersModelName: recommended
     DeviceSerialNumber: recommended
diff --git a/tools/schemacode/bidsschematools/tests/test_expressions.py b/tools/schemacode/bidsschematools/tests/test_expressions.py
index 5532ef38ba..33eff61000 100644
--- a/tools/schemacode/bidsschematools/tests/test_expressions.py
+++ b/tools/schemacode/bidsschematools/tests/test_expressions.py
@@ -1,7 +1,21 @@
+from collections.abc import Mapping
+from functools import singledispatch
+from typing import Union
+
 import pytest
 from pyparsing.exceptions import ParseException
 
-from ..expressions import ASTNode, expression
+from ..expressions import (
+    Array,
+    ASTNode,
+    BinOp,
+    Element,
+    Function,
+    Property,
+    RightOp,
+    expression,
+)
+from ..types import Namespace
 
 
 def test_schema_expressions(schema_obj):
@@ -77,3 +91,95 @@ def test_checks(schema_obj):
 def test_expected_failures(expr):
     with pytest.raises(ParseException):
         expression.parse_string(expr)
+
+
+def walk_schema(schema_obj, predicate):
+    for key, value in schema_obj.items():
+        if predicate(key, value):
+            yield key, value
+        if isinstance(value, Mapping):
+            for subkey, value in walk_schema(value, predicate):
+                yield f"{key}.{subkey}", value
+
+
+def test_valid_sidecar_field(schema_obj):
+    """Check sidecar fields actually exist in the metadata listed in the schema.
+
+    Test failures are usually due to typos.
+    """
+    field_names = {field.name for key, field in schema_obj.objects.metadata.items()}
+
+    for key, rule in walk_schema(
+        schema_obj.rules, lambda k, v: isinstance(v, Mapping) and v.get("selectors")
+    ):
+        for selector in rule["selectors"]:
+            ast = expression.parse_string(selector)[0]
+            for name in find_names(ast):
+                if name.startswith(("json.", "sidecar.")):
+                    assert (
+                        name.split(".", 1)[1] in field_names
+                    ), f"Bad field in selector: {name} ({key})"
+        for check in rule.get("checks", []):
+            ast = expression.parse_string(check)[0]
+            for name in find_names(ast):
+                if name.startswith(("json.", "sidecar.")):
+                    assert (
+                        name.split(".", 1)[1] in field_names
+                    ), f"Bad field in check: {name} ({key})"
+
+
+def test_test_valid_sidecar_field():
+    schema_obj = Namespace.build(
+        {
+            "objects": {
+                "metadata": {
+                    "a": {"name": "a"},
+                }
+            },
+            "rules": {"myruleA": {"selectors": ["sidecar.a"], "checks": ["json.a == sidecar.a"]}},
+        }
+    )
+    test_valid_sidecar_field(schema_obj)
+
+    schema_obj.objects.metadata.a["name"] = "b"
+    with pytest.raises(AssertionError):
+        test_valid_sidecar_field(schema_obj)
+
+
+@singledispatch
+def find_names(node: Union[ASTNode, str]):
+    # Walk AST nodes
+    if isinstance(node, BinOp):
+        yield from find_names(node.lh)
+        yield from find_names(node.rh)
+    elif isinstance(node, RightOp):
+        yield from find_names(node.rh)
+    elif isinstance(node, Array):
+        for element in node.elements:
+            yield from find_names(element)
+    elif isinstance(node, Element):
+        yield from find_names(node.name)
+        yield from find_names(node.index)
+    elif isinstance(node, (int, float)):
+        return
+    else:
+        raise TypeError(f"Unexpected node type: {node!r}")
+
+
+@find_names.register
+def find_function_names(node: Function):
+    yield node.name
+    for arg in node.args:
+        yield from find_names(arg)
+
+
+@find_names.register
+def find_property_name(node: Property):
+    # Properties are left-associative, so expand the left side
+    yield f"{next(find_names(node.name))}.{node.field}"
+
+
+@find_names.register
+def find_identifiers(node: str):
+    if not node.startswith(('"', "'")):
+        yield node