Section 5.2: Evidence Gathering Techniques: Interviews, Observations, and Document Review

Section 5.2: Evidence Gathering Techniques: Interviews, Observations, and Document Review

The Methodology of Information Collection

To evaluate whether a QMS conforms to ISO 9001:2015 criteria, an auditor must collect and verify evidence. ISO 19011:2018 Clause 6.4.7 outlines a systematic process for collecting information: identifying sources, gathering evidence through appropriate techniques, evaluating it against criteria to generate findings, and drawing conclusions.

Auditors should apply triangulation, cross-verifying evidence using all three methods to ensure findings are robust, reliable, and representative of the QMS's actual performance. The three techniques are:

1. Document Review (evaluating documented information)
2. Interviews (speaking with personnel at various levels)
3. Observation (watching activities, processes, and physical work environments)

Document Review: Verification of System Design and Records

Document review occurs in two phases: the preliminary review (evaluating system design before the onsite audit) and the detailed review (conducted onsite). In ISO 9001:2015, both "documents" (procedures, specifications) and "records" (evidence of completed activities) are consolidated under Documented Information (Clause 7.5). However, the auditor must treat them differently:

• System Design (Specifications): The auditor reviews policies, procedures, flowcharts, and quality objectives to determine if the system is designed in compliance with ISO 9001:2015 requirements. This establishes adequacy.
• System Execution (Records): The auditor reviews training logs, calibration certificates, audit reports, management review minutes, and inspection records to verify that the processes are being executed as defined. This establishes effectiveness.

During document review, the auditor must verify traceability, revision control, approval status, and readability. A common pitfall is spending too much time reviewing documents in an isolated room, rather than verifying their application on the shop floor or in office departments.

Interview Techniques: Engaging the Auditee's Personnel

Interviews are the most dynamic and often the most challenging part of an audit. According to ISO 19011:2018 Annex B.4, interviews should be held with persons from appropriate levels and functions performing activities within the scope of the audit.

The auditor should utilize the following interview principles:

• Establish Rapport: Begin with introductions and put the interviewee at ease. Explain that the audit is of the process, not the individual.
• Use Open-Ended Questions: Avoid questions that can be answered with a simple "yes" or "no." Instead, use the "5 Ws and 1 H" structure:
  • Who is responsible for this activity?
  • What happens if a nonconformity is detected?
  • Where are the inspection records stored?
  • When is the management review conducted?
  • Why is this specific sequence of steps followed?
  • How do you verify that this equipment is calibrated?
• Active Listening: Allow the interviewee to speak without unnecessary interruption. Pay attention to verbal and non-verbal cues. Summarize their responses to ensure mutual understanding ("If I understand correctly, you are saying that...").
• Handling Difficult Interviewees:
  • The Hostile Interviewee: Remain calm, polite, and objective. Reiterate the audit's purpose and focus on evidence.
  • The Overly Talkative Interviewee: Gently redirect the conversation back to the audit scope and specific questions.
  • The Reticent Interviewee: Ask simpler, more direct questions, and encourage them by showing interest in their work.
  • The Rehearsed Interviewee: Deviate from the standard sequence of questions and ask for live demonstrations or specific random examples to bypass scripted answers.

Observation of Processes and the Work Environment

Observation involves witnessing activities as they occur and assessing the physical conditions under which work is performed. Under ISO 9001:2015, observation is essential for auditing:

• Environment for the Operation of Processes (Clause 7.1.4): Verifying physical factors (temperature, lighting, hygiene, noise) and social/psychological factors where they affect product quality.
• Monitoring and Measuring Resources (Clause 7.1.5): Observing whether measuring devices are calibrated, properly stored, and used correctly by operators.
• Operational Control (Clause 8.1): Watching production lines or service delivery to see if process steps match documented work instructions.
• Identification and Traceability (Clause 8.5.2): Checking if materials, work-in-progress, and finished goods are clearly labeled to prevent mix-ups.

Practical Scenario: Auditing Design and Development (Clause 8.3)

To illustrate triangulation, consider an auditor evaluating an organization's Design and Development process:

1. Document Review: The auditor reviews the Design and Development Procedure (specification) and selects three project files. They inspect the Design Input records, Design Review minutes, and Design Verification/Validation reports (records).
2. Interviews: The auditor interviews the Design Manager and a project engineer, asking how they determine design inputs and manage design changes.
3. Observation: The auditor visits the engineering lab, observing how engineers use CAD software to model stress tests, and checks if the CAD database maintains revision controls that match the approved design inputs. By combining these three sources, the auditor obtains a complete picture of Clause 8.3 compliance.

Comparison of Evidence Gathering Techniques

The table below contrasts the three evidence gathering techniques: