Breach Definition and Risk Assessment: The four-factor analysis and the presumption

45 CFR 164.402 is the requirement on breach definition and risk assessment. It is short to read and easy to underestimate, because satisfying it means producing evidence rather than holding an intention.

What the rule says

45 CFR 164.402 governs breach definition and risk assessment. The operative text is not reproduced here: read it at the source linked below, because the conditions in it are the requirement and a summary of a conditional rule is not a safe substitute for the rule.

Where encryption takes PHI outside the notification duties, it is because of how 45 CFR 164.402 defines unsecured protected health information: PHI "that is not rendered unusable, unreadable, or indecipherable to unauthorized persons through the use of a technology or methodology specified by the Secretary in the guidance issued under section 13402(h)(2) of Public Law 111-5."

What this looks like in practice

In an assessment, 45 CFR 164.402 is not one question. It resolves into several, and each one is really asking for different evidence. These are among the questions asked about it:

• Does the organization have a documented breach notification policy that defines what constitutes a notifiable breach and the risk-assessment process used to determine whether notification is required?
• Does the organization apply the §164.402 breach standard correctly, treating any impermissible acquisition, access, use, or disclosure of PHI as PRESUMED to be a breach unless it documents a low probability that the PHI has been compromised, based on the four required factors, and does it recognize the three exceptions and the encryption safe harbor?

Ownership usually sits with the privacy and security officials, though the evidence is often produced by someone else, which is where the trail breaks. A control that works but has no owner tends to stop working the month the person who quietly maintained it changes roles.

Who this applies to

Covered entities. A business associate is bound directly by the provisions that name it (for example 45 CFR 164.502(a)(3), the minimum necessary standard at 164.502(b), and 164.410) and otherwise through its business associate agreement, so read the provision for whom it names. The Privacy Rule has no counterpart to the Security Rule's flexibility-of-approach clause (164.306(b)). Instead, 45 CFR 164.530(i)(1) requires policies and procedures reasonably designed for the size and type of your activities, and any deadline a provision sets applies at every size. A business associate is bound directly by this provision; it is not only a contract term.

Building it, in order

The sequence below is the order that produces evidence as a by-product rather than as a separate documentation exercise:

1. Maintain a breach notification policy that defines a notifiable breach and any recognized exceptions.
2. Document the risk-assessment process used to determine whether a security event requires notification, including the factors evaluated.
3. Define workforce roles and responsibilities in the determination process.
4. Require the determination and its basis to be documented for each event.
5. Adopt a written breach risk-assessment form that starts from the presumption rather than from a judgment call, and that requires a recorded finding on each of the four 45 CFR 164.402 (the definition of breach, paragraph (2)) factors before any no-breach conclusion can be reached. Include a checklist for the three 45 CFR 164.402 (the definition of breach, paragraph (1)) exceptions, good-faith unintentional acquisition by a workforce member acting within scope, inadvertent disclosure between persons authorized at the same organization or organized health care arrangement, and a good-faith belief the recipient could not reasonably have retained the information, noting that the first two also require no further impermissible use or disclosure. Record the encryption status of the affected data, because encrypted PHI meeting the HHS guidance is not unsecured PHI and does not trigger notification. Retain every completed assessment for six years from the date of its creation or the date when it last was in effect, whichever is later, including those concluding no breach occurred, since a no-breach determination you cannot evidence is indistinguishable from a breach you failed to report.

Where else this maps

The questions behind 45 CFR 164.402 also map to HHS 405(d) HICP (2023 Edition) CSP 8, which is voluntary guidance rather than law; following it does not by itself establish compliance with any law. That matters for scoping: the same evidence can be written once and referenced from each, rather than rewritten per framework.

Evidence an assessor asks for

For this requirement the evidence types that satisfy it are policy and procedure. The distinction matters more than it looks: a policy states what you intend to do, a procedure states how, and a record proves it happened on a date. Auditors ask for all three, and a practice that has written the first two often has nothing for the third.

Date every document and keep the superseded versions. Under 45 CFR 164.530(j)(2) the documentation 164.530(j)(1) requires (applied to a covered entity by 164.414(a)) is kept six years from the date of its creation or the date when it last was in effect, whichever is later. It is the same period the Security Rule sets at 164.316(b)(2)(i), under a different provision, so cite the one that governs the document you are holding.

Where this usually goes wrong

In our question bank this is weighted Critical: a gap here is raised as a critical finding (a partial answer as high). The usual cause of a gap is drift: the control was implemented once, the environment changed, and nothing re-checked it. A dated review on a fixed cadence is cheaper than the remediation.

What to do about it

• Produce the evidence, not the intention. For 45 CFR 164.402 that means a signed, dated policy with a named owner and a review date and a step-by-step procedure someone unfamiliar with the task could follow. If the only evidence is that someone knows how this works, you have a practice and not a record.
• Put a name on it. Your privacy and security officials should be recorded as the owners. A control with no owner stops working the month the person who quietly maintained it changes roles, and nobody notices.
• Review it on a fixed date, not when you remember. In our question bank this is weighted Critical: a gap here is raised as a critical finding (a partial answer as high). Put the review on the calendar with an owner, and keep the dated output of each one.

The practical test for 45 CFR 164.402 is whether someone unfamiliar with your organization could read your documentation and tell what you do, who does it, and when it last happened. If they can, the documentation will hold up; whether the requirement is met is a judgment about what it shows, and your counsel owns that conclusion. If they need you in the room to explain it, it will not.

Related requirements

• Individual Breach Notification: The 60-day deadline and required content
• Media Notification: The more-than-500-residents threshold
• Notification to the Secretary: The two HHS deadlines and which applies

References

• 45 CFR 164.402, in 45 CFR 164.402 on eCFR.
• Crosswalk references in this post are the mappings in our question bank, and are not verified against the published text of those standards.
• This post describes what a requirement asks for and what evidence documents it. It is not legal advice, and your counsel owns the conclusion. State law may impose stricter obligations (45 CFR 160.203).