Episode 47 — Verify and Validate Evidence So Findings Are Defensible and Repeatable
In this episode, we focus on one of the most important but least glamorous parts of assessment work: verifying and validating evidence so that your findings can stand up to scrutiny and can be repeated by someone else. If you take nothing else from this topic, take this idea: a finding is only as strong as the evidence behind it and the logic connecting that evidence to the requirement. Beginners sometimes assume that once evidence is collected, the hard part is over, but in practice, the hard part often starts when you try to decide what the evidence actually proves. Verification is about confirming that evidence is authentic, complete enough, and relevant to the time period and scope. Validation is about confirming that the evidence supports the claim you are making and that the claim matches the criteria you are assessing against. When you do both well, your assessment becomes defensible, meaning it can be challenged and still hold, and repeatable, meaning another assessor using the same methods could reach the same conclusion. That is what separates a professional assessment from a collection of opinions.
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A good starting point is understanding what makes evidence weak, because weaknesses in evidence are often subtle. Evidence can be weak because it is outdated, because it applies to a different environment than the one in scope, because it is incomplete, or because it is self-referential, meaning it proves only that someone said something. For example, a policy document might be signed and dated, but if it has not been updated in years and the environment has changed, it may not reflect current operations. A procedure might describe a process, but if no records exist showing the process is actually performed, it may not support an operational claim. A screenshot might look convincing, but if you cannot tie it to the correct system or time, it becomes questionable. Evidence can also be inconsistent, such as two documents describing different control frequencies, which indicates that the control environment may not be aligned. Verification is how you detect these weaknesses early rather than discovering them after you have already written conclusions. In governance work, it is better to be cautious and precise than to be fast and confident without support.
Verification begins with basic authenticity and provenance, which means you know where the evidence came from, who provided it, and whether it is what it claims to be. You do not have to treat every document like a criminal investigation, but you do need enough provenance to be confident in what you are relying on. If you receive a report, you should know whether it is an official system-generated report or a manually assembled spreadsheet. If you receive a policy, you should know whether it is the approved version or a draft, and whether it is owned by the right governance authority. If you receive a vendor assurance document, you should know its date and scope, and whether it covers the service actually used. Authenticity also includes checking for signs of modification, such as inconsistent formatting or missing metadata, though you should approach this professionally and neutrally. The aim is not to accuse anyone but to ensure your conclusions are built on stable ground. Provenance is also part of repeatability, because another assessor should be able to locate the same evidence source.
Next is verifying relevance to scope, which is a frequent source of accidental error. Evidence can be real and accurate and still be irrelevant if it applies to a different system, a different business unit, or a different environment. A common example is receiving documentation for a development environment when the assessment is scoped to production, or receiving a policy that applies company-wide when the system has an approved exception. Another example is receiving a report from a shared service team that covers many systems, but you need to confirm it includes the system in scope. Verification means you confirm that the evidence actually maps to the asset boundary you are assessing and to the requirements you are evaluating. If the evidence is only partially relevant, you document the limitation and decide whether additional evidence is needed. This is also where you watch for scope drift, where evidence pulls you toward assessing things you did not plan to assess. Staying disciplined about relevance keeps the assessment focused and helps ensure that findings are about the right target, not a neighboring system that happened to be better documented.
Time is another dimension of verification that beginners sometimes overlook, yet it is critical for proving operation. Many controls are not one-time events; they are recurring activities like access reviews, log review, backups, patching cycles, and incident response exercises. Evidence must cover an appropriate time window to support a claim that the control operates routinely, not just that it happened once. If a control is supposed to be quarterly, a single record from one quarter may not be enough to claim consistent operation. Verification includes checking dates, ensuring the period aligns with what is being claimed, and ensuring there are no unexplained gaps. It also includes ensuring that evidence is not too fresh to represent normal behavior, such as documents created only because the assessment started. That does not mean new evidence is invalid, but it can indicate that the control was not operating previously. A defensible assessment separates evidence that shows ongoing operation from evidence that shows a response to scrutiny. When you verify time coverage carefully, your conclusions become much harder to challenge.
Completeness and sampling are also part of verification, because evidence can be selectively presented without anyone intending to mislead. A team might provide the best examples they can find, which is natural, but an assessment needs to know whether those examples are representative. Verification includes confirming the size of the population, such as the total number of privileged accounts, the total number of changes, or the total number of incidents, and then ensuring your sample makes sense relative to that population. It also includes checking whether the evidence includes exceptions and failures, because a control environment that never shows an exception is often a sign that records are incomplete. Completeness does not mean you need everything, but it does mean you need enough to support the level of confidence the assessment requires. If evidence appears incomplete, a rigorous assessor will expand sampling, request additional records, or document an evidence limitation rather than quietly accepting a thin set. This is one of the most common ways defensibility is lost, because stakeholders can later argue that the assessment relied on an unrepresentative subset. Verification is how you close that door.
Validation comes next, and validation is where you test the logic of the evidence against the criteria and against the claim you want to make. This is where you ask, does this evidence actually demonstrate compliance, effectiveness, or operation in the way the requirement expects. For example, a requirement might say access must be approved by a manager and reviewed regularly, and you might have evidence of approvals but no evidence of periodic review. Validation would prevent you from concluding the control is fully met when only part of it is demonstrated. Another example is a requirement for logging of specific event types, where you might have evidence that logs exist, but validation requires you to confirm they include the required event categories and are retained for the required duration. Validation also includes checking that your interpretation is correct, which is where subject matter expertise and careful reading matter. If you misunderstand what a record represents, you can reach incorrect conclusions even with authentic evidence. Validation is essentially the discipline of not overstating what evidence proves.
A key validation technique is triangulation, meaning you use multiple evidence types to support the same conclusion. Interviews can tell you how a process is supposed to work, procedures can document the intended steps, and operational records can show that the steps occurred. When those align, your conclusion is stronger. If they do not align, you have work to do to understand why, and that work often reveals the real control weakness. Triangulation also helps you avoid single-point failure in your evidence set, where one document being questioned would undermine the whole conclusion. For example, if you rely on a single policy to claim a control exists, someone can argue that policies are not followed, and they may be right. If you also have recurring records and validated outputs, that argument becomes weaker. Triangulation does increase effort, so you apply it most strongly to high-risk controls and high-stakes requirements. The principle is that the more important the conclusion, the more supporting angles you want. That is how you make findings defensible without trying to verify everything to infinity.
Another important part of validation is dealing with contradictions and edge cases in a controlled way. Contradictions might appear as different versions of a procedure, conflicting statements from different interviewees, or records that do not match claimed frequency. A rigorous approach does not ignore contradictions, but it also does not automatically treat them as evidence of failure. Instead, you treat contradictions as questions that must be resolved, either by finding authoritative governance documents, by confirming which process is actually used, or by analyzing operational records across time. Sometimes contradictions reveal that different teams follow different processes, which might mean the control is inconsistently implemented. Sometimes they reveal that the control changed recently, which affects how you evaluate the time period in scope. Validation is where you make these distinctions and ensure the finding reflects reality rather than assumptions. This is also where you learn to document limitations clearly when contradictions cannot be fully resolved within the scope and schedule. A defensible report can include an evidence limitation, as long as it is explained plainly and tied to the impact on confidence.
Repeatability depends heavily on how you document verification and validation steps, because another assessor needs to understand not only what evidence you used, but how you evaluated it. This does not mean writing a novel, but it does mean capturing key details: what requirement was evaluated, what evidence sources were reviewed, what time period the evidence covered, what samples were selected and why, and what criteria were used to determine whether the requirement was met. Repeatability is one reason assessments often use evidence logs or traceability records, because these structures keep evidence linked to conclusions. If a finding is challenged, you can point to the evidence trail and show that your conclusion followed a consistent method. If a future assessment happens, the team can reuse the approach and compare results over time, which supports continuous improvement. Repeatability also protects the organization, because it reduces dependence on individual assessors’ style or memory. When the assessment method is repeatable, governance decisions become more stable and less vulnerable to personality or politics.
There is also a human side to verification and validation, because evidence often comes from people who are busy and sometimes anxious. When you request additional evidence or question the relevance of what you received, it can feel to stakeholders like you do not trust them. The way you communicate matters, and rigor should be paired with professionalism. You can explain that verification is about making the assessment defensible, not about doubting anyone’s competence, and that validating evidence protects the organization by ensuring decisions are based on facts. It helps to be specific in follow-up requests, such as asking for records for a particular time window or asking for evidence that shows approval and review, rather than vaguely asking for more. You also need to avoid moving the goalposts, which means your criteria should stay stable and you should align requests with what the plan established. When stakeholders understand that you are applying consistent standards, cooperation usually improves. Verification and validation done with respect can strengthen trust rather than harm it.
By the end of this topic, you should see verification and validation as the core quality controls that turn collected materials into defensible and repeatable findings. Verification confirms authenticity, relevance, time coverage, and completeness so you know the evidence is solid and applicable. Validation confirms that the evidence actually supports the claim and matches the requirement criteria, using triangulation and careful interpretation to avoid overstatement. Together, they create a discipline that protects the assessment from bias, misunderstanding, and selective evidence. When someone asks, how do you know, you can answer with a clear evidence trail and a consistent method rather than with confidence alone. That is what makes assessment work credible in governance, risk, and compliance contexts, and it is what allows the assessment results to be used for real decisions without fear that they will collapse under challenge. In a world where organizations are judged by what they can prove, verification and validation are how you make proof real.
