Risk Assessment: CQA/CPP/CMA Criticality Ranking (QbD)

This is a ready-to-use QbD criticality risk assessment. It runs in two stages because the two questions it answers are different: which quality attributes are critical at all (a severity question, independent of how well the process is controlled), and which process parameters and material attributes are critical because they actually move a critical attribute (an impact, occurrence, and detection question). Collapsing the two into one scale is a common source of flawed criticality decisions. Replace every <<FILL: ...>> placeholder with your own specifics. A worked filled specimen follows the template. Verify each cited regulation against the current source before you rely on it.

Document control header

Field	Entry
Document title	CQA/CPP/CMA Criticality Ranking Risk Assessment
Document number	`<<FILL: RA-ID, e.g. RA-PD-022>>`
Version	`<<FILL: version, e.g. 1.0>>`
Effective date	`<<FILL: effective date>>`
Product / process	`<<FILL: product name, unit operations in scope>>`
Document owner	`<<FILL: role, e.g. Head of Process Development>>`
Source QTPP	`<<FILL: QTPP document number and version>>`

1. Purpose

This assessment converts the Quality Target Product Profile into a documented, defensible set of Critical Quality Attributes (CQAs), then maps process parameters and material attributes against those CQAs to classify each as a Critical Process Parameter (CPP), a Critical Material Attribute (CMA), a key (non-critical but monitored) parameter, or non-critical. It exists so that every parameter carried into DoE, and every parameter later written into the control strategy, has a documented, scored rationale rather than an unwritten judgment call.

2. Scope

This assessment covers every candidate quality attribute listed in the QTPP named above, and every process parameter and material attribute across the unit operations in scope. It does not itself run the DoE; it decides what enters the DoE program and, after the DoE data exist, is revisited to confirm or revise the classification against measured effects.

3. Responsibilities

Role	Responsibility
Quality Risk Management facilitator	Runs the risk-assessment sessions, keeps scoring consistent across attributes and sessions, maintains the record.
Process development / formulation SME	Provides the cause-and-effect knowledge behind each parameter-CQA link and each severity call.
Analytical development	Confirms whether a candidate CQA can actually be measured, and with what precision, before it is scored.
Quality Assurance	Reviews and approves the completed assessment and any later revision.
Statistician / DoE specialist	Confirms the assessment’s medium- and high-risk items are the set that will actually be studied in the DoE program.

4. Methodology

Stage 1, CQA criticality, scores each candidate quality attribute on severity of harm to the patient alone if the attribute falls outside an acceptable range. Severity does not change with how well the attribute is currently controlled; an attribute can score high severity and still be low overall risk once a control is in place. This stage answers “is this attribute a CQA,” independent of process knowledge.

Stage 2, CPP/CMA criticality, is run only for CQAs designated in Stage 1. Each candidate process parameter or material attribute affecting a CQA is scored on severity (carried from the CQA’s Stage 1 score), occurrence (the probability that normal process variability moves the parameter enough to matter), and detection (the probability the shift would be caught before it affects the product; a higher score means harder to detect). This is a standard failure mode and effects analysis (FMEA) structure applied to the parameter-to-CQA relationship, consistent with the ICH Q9(R1) risk management toolset. The resulting risk priority number (RPN) is used to rank and prioritize, never as the sole basis for excluding a high-severity item from scope.

5. Scoring scales

5.1 Stage 1: CQA criticality (severity only)

Score	Level	Definition	Example
1	Negligible	No meaningful effect on safety or efficacy if out of range; cosmetic or administrative only	Tablet color shade variation within a stated range
2	Minor	A detectable effect on a secondary characteristic with no direct patient safety or efficacy consequence	A minor shift in an intermediate in-process measurement with no traced effect on a downstream result
3	Major	Could affect efficacy, such as bioavailability or potency, or narrows a safety margin that is otherwise controlled	Dissolution rate affecting bioavailability; a process-related impurity within, but near, a qualified limit
4	Critical	Directly determines patient safety or efficacy: identity, strength/potency, a safety-limiting impurity, sterility, or an immunogenicity-linked attribute	Assay/potency, sterility for a parenteral product, a confirmed immunogenic aggregate species

Attributes scoring 3 or 4 are designated CQAs. An attribute scoring 1 or 2 that is nonetheless carried forward as an in-process attribute because it drives a true CQA (for example tablet hardness driving dissolution) is documented as such, not silently dropped.

5.2 Stage 2: CPP/CMA criticality (severity x occurrence x detection)

Score	Occurrence (likelihood normal variation moves the parameter enough to matter)	Detection (likelihood a meaningful shift is caught before it affects the product; higher = harder to detect)
1	Rare: parameter is tightly controlled by design or equipment (for example, an automated closed-loop control)	Readily detected: continuous or in-line monitoring with an immediate alert
2	Occasional: parameter has some operator- or lot-dependent variability but a track record of staying near target	Likely detected: routine in-process check before the next step
3	Frequent: parameter is known to drift or vary meaningfully across batches, operators, or material lots	Unlikely detected before use: only caught at end-product testing, after the batch is committed
4	Near-certain: parameter has no direct control and depends on upstream conditions or supplier variability	Essentially undetectable until a downstream failure or complaint surfaces it

Severity for Stage 2 is carried directly from the affected CQA’s Stage 1 score (1 to 4). RPN = Severity x Occurrence x Detection, range 1 to 64.

6. Classification bands and the override rule

RPN	Classification	Action
1 to 8	Non-critical	Monitor only if warranted for process consistency; no CPP/CMA designation
9 to 24	Key parameter (KPP) / potential CPP	Advance to DoE; classify formally once effect size is measured
25 to 64	CPP / CMA	Control formally: setpoint and range in the batch record or incoming material specification, in-process control, written into the control strategy

Override rule: any parameter or material attribute affecting a CQA scored Critical (severity 4) in Stage 1 stays in the DoE scope and the control-strategy discussion regardless of a low occurrence or detection score. A low RPN driven by occurrence or detection never removes a high-severity failure mode from scope; it only affects how the parameter is controlled once studied.

7. Assessment table

7.1 Stage 1: CQA criticality

Candidate quality attribute	Severity (1 to 4)	CQA? (Y/N)	Rationale
`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`
`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`
`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`

7.2 Stage 2: CPP/CMA criticality

Unit op	Parameter / material attribute	CQA affected	Severity	Occurrence	Detection	RPN	Classification
`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`
`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`
`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`

8. Mitigations

Parameter / attribute	Classification	Mitigation / control proposed	Owner	Target date
`<<FILL>>`	`<<FILL>>`	`<<FILL: DoE study planned, in-process control added, supplier specification tightened>>`	`<<FILL>>`	`<<FILL>>`

9. Residual risk and approval

Field	Entry
Total attributes assessed (Stage 1)	`<<FILL>>`
CQAs designated	`<<FILL>>`
Total parameters/attributes assessed (Stage 2)	`<<FILL>>`
CPPs/CMAs designated	`<<FILL>>`
Items advanced to DoE	`<<FILL>>`
Residual risk statement	`<<FILL: e.g. "acceptable pending DoE confirmation of KPP-classified items">>`
Completed by (name, role, date)	`<<FILL>>`
QA approval (name, signature, date)	`<<FILL>>`

References

ICH Q8(R2), Pharmaceutical Development (CQA and CPP definitions, criticality as a continuum). ICH Q9(R1), Quality Risk Management (the FMEA/risk-ranking methodology and formality-proportionate-to-risk principle). ICH Q11, Development and Manufacture of Drug Substances (CMA concept applied to drug substance inputs). ICH Q10, Pharmaceutical Quality System (maintaining the assessment as a living document).

Confirm the current version of each reference before issue.

Revision history

Version	Date	Author	Summary of change
`<<FILL: 1.0>>`	`<<FILL: date>>`	`<<FILL: author>>`	Initial issue.

Approvals

Role	Name	Signature	Date
Author	`<<FILL>>`
Reviewer (Statistician / DoE specialist)	`<<FILL>>`
Approver (Quality Assurance)	`<<FILL>>`

Filled specimen

The following shows both stages completed for an illustrative lyophilized biologic drug product. The company, product, and numbers are illustrative; replace them with your own.

Stage 1 (excerpt)

Candidate quality attribute	Severity	CQA?	Rationale
Potency (bioassay)	4	Yes	Direct measure of therapeutic activity
Aggregate content	4	Yes	Linked to immunogenicity risk
Moisture content (residual)	3	Yes	Drives long-term stability and aggregation over shelf life
Reconstitution time	2	No, but carried as in-process attribute	No direct patient-safety consequence, but an early signal of cake structure affecting moisture and potency
Cake appearance	1	No	Cosmetic, no traced effect on any CQA

Stage 2 (excerpt)

Unit op	Parameter	CQA affected	Severity	Occurrence	Detection	RPN	Classification
Lyophilization, primary drying	Shelf temperature	Moisture content	3	3	3	27	CPP
Lyophilization, primary drying	Chamber pressure	Moisture content	3	2	3	18	KPP, study in DoE
Lyophilization, freezing	Freeze rate	Aggregate content	4	3	4	48	CPP (override rule applies regardless of any lower band)
Formulation	Fill volume	Potency (per-vial dose)	4	2	1	8	Non-critical by RPN, but stays in scope under the override rule because severity is Critical
Formulation	Buffer pH at fill	Aggregate content	4	2	2	16	KPP, study in DoE

Residual risk statement: acceptable pending DoE confirmation of the two KPP-classified items (chamber pressure, buffer pH); freeze rate is already classified CPP under the override rule and is studied first.

Common inspection findings this risk assessment prevents

CQA criticality downgraded because the attribute is currently well controlled, conflating severity with risk.
A high-severity parameter screened out of the DoE program purely because occurrence and detection scores diluted its RPN.
Stage 2 scoring run without first completing Stage 1, so parameters are ranked against attributes that were never formally confirmed as CQAs.
No documented rationale for an attribute excluded as non-critical, leaving the exclusion unsupported months later.
A classification that is never revisited after DoE data exist, so the filed criticality no longer matches what the data actually show.

How to adapt this risk assessment

Set your document number, product, and source QTPP reference in the header.
Add a row in section 7.1 for every candidate attribute in your QTPP; do not pre-filter before scoring.
Run section 7.2 only for attributes designated CQA in Stage 1; add a row for every parameter or material attribute your cause-and-effect analysis (for example an Ishikawa diagram) surfaces.
Keep the override rule in section 6 non-negotiable; if your organization uses different RPN bands, the override rule still applies at whatever severity level you define as Critical.
Feed the DoE-scope items from section 9 directly into the DoE study protocol, and revisit this assessment once DoE results exist.