Anonymous reports arrive through hotlines, letters and emails. They cannot be ignored, and they cannot always be resolved.

Assess the specificity. A report with names, dates, amounts and documents can be investigated. A general assertion that something is wrong in a department usually cannot, and the response should be proportionate.

Do not attempt to unmask the reporter. Investigating the source rather than the allegation is retaliation in substance and is treated as such.

Follow-up mechanism. Good hotline systems allow anonymous two-way communication through a case number. Use it to ask clarifying questions, which frequently converts an unactionable report into an actionable one.

Corroboration. Documents, systems data and transaction records can substantiate a specific allegation without any complainant.

Document the assessment. Where a report cannot be investigated, record why, what was considered, and what monitoring was put in place. An unexplained decision to take no action is the finding.

Pattern analysis. Repeated anonymous reports about the same area, each individually thin, are collectively significant and should trigger escalation.

Feedback. Where the channel permits, tell the reporter that the matter was reviewed. Reporters who hear nothing go elsewhere next time.