An investigation evidence matrix is a way to review a question alongside the information that supports, conflicts with or leaves it unresolved. It can help an investigator, internal reviewer or analyst avoid a familiar mistake: reaching a conclusion from a summary while losing track of the original sources.
A matrix is an organizational index. It does not establish authenticity, admissibility, chain of custody or whether an account is true. Those decisions require appropriate procedures and review.
What should an evidence matrix contain?
Keep each issue distinct from the records that may relate to it. A useful set of fields can include:
- Issue or question: precisely what needs to be resolved.
- Source reference: a stable source ID, document ID or authorized repository reference.
- Information recorded: a neutral summary of what the source actually states or depicts.
- Relationship to the issue: supporting, conflicting, contextual or not yet assessed.
- Verification status: whether the source's origin, completeness and meaning have been checked.
- Known limitations: missing pages, uncertain dates, indirect reporting or other constraints.
- Required follow-up: a discrete action, with an owner, status and review date.
Use consistent references like SRC-001 and EVT-002. This makes it possible for a reader to find the source without embedding sensitive material in the matrix itself.
Worked example: one issue, three different records
Imagine a fictional workplace equipment-review file. The central question is whether a required inspection was documented before the reported incident. Below is an example of how to keep reported information separate from findings.
| Source | Reported information | Status or limitation | Follow-up |
|---|---|---|---|
|
SRC-001 Interview note |
Staff member recalls an inspection on October 12. | Reported recollection; not independently verified. | Clarify who conducted it. |
|
SRC-002 Maintenance log copy |
An entry bears an October 13 date. | Original, completeness and authorship unconfirmed. | Request original signed log. |
|
SRC-003 Operations schedule |
Shows inspection work allocated to October 12. | A scheduled task is not proof it occurred. | Compare with completion records. |
What the matrix shows: the dates differ, and the schedule alone cannot resolve the issue. A reviewer can identify the conflict and the next records needed without prematurely deciding which account is correct.
What it does not show: that a violation occurred, that an account is dishonest, or that any record meets an organization’s evidence-preservation requirements.
Five steps to build a dependable working matrix
- Define the questions. Break broad allegations or issues into reviewable questions. Avoid headings that assume the conclusion.
- Index the sources. Give each record or account a stable ID and note where the original is properly stored.
- Describe the content neutrally. Record what the source says, not the interpretation you hope it supports.
- Document conflicts and gaps. Missing material and contrary accounts should be as visible as corroborating information.
- Create follow-up work. Link unresolved issues to assigned tasks and track how each one was addressed.
Evidence log, source log and matrix: what's different?
An evidence or item log is an inventory of records or materials. A source log focuses on origin, attribution, receipt and review status. An issue matrix helps a reviewer compare those sources against specific questions. The same source can appear in several issue rows, but the source ID should remain consistent.
These resources may complement each other. A source index answers “where did this information originate?”; the matrix answers “how does it relate to this unresolved question?”
A practical quality-control checklist
- Can a reviewer locate the original source from every important row?
- Are reported statements distinguishable from independently verified observations?
- Are dates, source versions and missing pages clearly noted?
- Are conflicting accounts included rather than edited away?
- Does each unresolved material question have an owner and next action?
- Does the summary accurately reflect what the underlying records support?
Run this review using fictional or suitably de-identified sample information before adapting the structure to any authorized case. The matrix itself is not secure evidence storage: keep original records in approved systems, with the access, retention and chain-of-custody safeguards that apply to your work.
Where CaseWorks fits
For focused source documentation: the $19 CaseWorks Source & Evidence Documentation Pack helps organize sources, item records, review status, conflicts, limitations and outstanding checks. Read the product page for the precise delivered files; the purchase is a downloadable organizational resource, not a secure evidentiary system.
For linking the matrix to broader casework: compare the $79 Investigation Case File & Case Management System, which organizes timelines, leads, sources, interviews, actions and review as a connected documentation workflow.
To try the method first: use the free Investigation Timeline Template to practice source references and verification labels before adding a separate issue matrix.
Frequently asked questions
Does an evidence matrix establish chain of custody?
No. It is a working reference tool and does not replace physical or digital evidence-handling procedures, forensic validation, documented custody records or admissibility determinations.
Should every source be marked supporting or conflicting?
No. Contextual, incomplete and not-yet-assessed information should retain honest labels. Forcing every source into a binary category can hide uncertainty.
Can a source relate to more than one issue?
Yes. Keep one stable source ID and cite it wherever relevant; avoid creating inconsistent duplicate descriptions.
General documentation guidance only. Follow relevant laws, privacy policies, professional standards and supervisory procedures. No legal or evidentiary conclusions are provided.