Changing an approved Purdue Global study: modifications, amendments and what must wait for approval
Approval is granted to a drawing, not to an intention. Once the letter exists, the study you may run is the study the board read — and the default rule, stated in Purdue Global's own amendment procedure and in the federal rule behind it, is that a change is reviewed and approved before it is implemented, not after. The exceptions are real but narrow, and every one of them still ends with a document going to the board. This sheet sorts what waits, what does not, and what has stopped being an amendment altogether.
Short answer
Assume the change waits. Purdue Global requires an amendment reviewed and approved before implementation for any change to an approved study. Narrow exceptions exist — immediate hazard, rescheduling, editorial corrections, same-medium recruitment — and even those require updated documents for the file.
What counts as a change to an approved study?
More than most candidates expect. Purdue Global's SOP 305 uses amendment and modification interchangeably and defines the pair as a change to IRB-approved research that must have review and approval before implementation. Its Amendment Guidance Sheet, citing 45 CFR 46.108(a)(3), lists the territory: changes to study procedures, changes to recruitment methods or materials, changes to consent documents, and changes that affect risk, benefits or the participant's experience — with the phrase "including but not limited to" doing deliberate work at the front of that list.
The federal source says the same thing from the institution's side. Under 46.108(a)(3)(iii), a board must have written procedures ensuring prompt reporting of proposed changes and ensuring that investigators run the activity on the terms the approval set, until proposed changes have been reviewed and approved — except where a change must be made immediately to end a hazard facing a participant. Everything in this sheet is an elaboration of that one sentence.
Which changes may be made before the board sees them?
Four narrow classes, drawn from SOP 305 and the guidance sheet, and each carries a tail obligation.
- An immediate hazard to participants. Where a change is needed at once to eliminate a hazard, it does not wait for review — but the board must be notified immediately afterwards, and SOP 305 names the reporting instrument for that: the unanticipated problem or adverse event report.
- Rescheduling. Moving a data collection when a participant misses an appointment, or where collection is incomplete for reasons outside the plan, provided the change does not increase risk.
- Editorial corrections. Grammar and language fixes to instruments, recruitment materials or consent documents made to improve participants' understanding.
- Recruitment inside the approved medium. Moving the same approved wording within the same medium. Changing medium is substantive.
SOP 305 also allows removing an instrument, provided that removal does not reduce a previously identified direct benefit to participants or weaken the study's validity — a narrower permission than it first sounds, since most instruments are load-bearing for a research question.
The tail obligation is uniform. Even where prior approval is not required, updated documents must still reach the board so the study file stays accurate. Purdue Global says this twice, in two documents, which is usually a sign of how often it is skipped.
What do the board's own worked examples show?
The Amendment Guidance Sheet includes scenarios, and they are more instructive than any general rule because they show where the line actually falls.
| The change | Prior approval? | The board's reasoning |
|---|---|---|
| Recruitment is going well; enrol more participants than approved | Yes | A change to the approved enrolment target is a substantive modification, and must be approved before the additional participants are enrolled. |
| Recruitment is going poorly; enrol fewer than approved | Yes | Changing the approved sample size is substantive either way — it affects the study design, not just the arithmetic. |
| Post the approved recruitment wording to another group on the same platform | No | A pivot within the same approved medium — but the updated materials still go to the board so the file stays accurate. |
| Turn the approved text post into an image for a different platform | Yes | An alteration of recruitment media, from text to image; and where the approval named one platform, another may be read as a different medium. |
Two things are worth extracting. First, the sample figure is protected in both directions — the intuition that shrinking a study is always safer than growing it does not survive contact with this guidance. Second, medium is judged by form as well as by platform: text to image is a change even when the platform stays put. If your recruitment plan is likely to need adjusting under pressure, the time to draw its alternatives is before the first approval, not after the response rate disappoints.
What does a modification submission contain?
SOP 305 sets the packet, and the guidance sheet repeats it as a checklist. Expect all of the following, filed through the university's current post-approval route:
- The completed electronic modification form.
- Authorisation from the faculty member or supervisor, documented or recorded in the electronic system.
- A revised application documenting the modified protocol, using tracked changes.
- Copies of every altered study material, also tracked — recruitment materials, consent forms, data-collection forms, supporting agreements.
- For external projects involving procedural changes, the board may ask for confirmation that a sponsor has approved the change.
Tracked changes are not a courtesy here; they are the named requirement in both documents. The reviewer is being asked to approve a delta, and a clean file forces them to reconstruct one. The same propagation discipline that governs a pre-approval revision governs an amendment: a dimension that changes must change in every document that carries it, or the modification introduces a fresh disagreement into a file that was previously consistent. That mechanics is worked through in the sheet on revision responses.
Is the review of an amendment lighter than the original?
The procedure can be lighter; the standard is not. SOP 305 says the criteria for approval are the same as for initial review, and that to approve a modification the board must determine that all of the approval criteria continue to be met once the change is implemented. Purdue Global's reviewer worksheet says the same from the other direction — its criteria list is marked as applying to initial, continuing and modification reviews alike.
Where the change is minor, review can run by expedited procedure. The federal rule allows it explicitly: 45 CFR 46.110(b)(1)(ii) puts minor changes to research already approved, made inside the window the approval covers, on the expedited list. SOP 305 defines a minor change as one that introduces no new risks and does not negatively alter the risk-benefit analysis, offering a revised project title, an alteration of recruitment media, or a reduction of interventions that leaves the risk-benefit ratio untouched as examples. Note what that means in practice: minor is a judgement about risk, not about effort. A change that takes you five minutes to make can still be substantive.
When does a change stop being an amendment?
When it stops being the same study. The guidance sheet draws the line plainly: extensive modifications that significantly change the procedures, or that address new research questions or hypotheses, are generally not modifications and should be submitted as a new study. This is the most expensive discovery to make late, and the easiest to make early. If you find yourself writing an amendment that rewrites the objectives, you are writing a protocol.
What about exempt studies, and about participants already enrolled?
Exempt studies get stricter treatment, not looser. SOP 305 requires an investigator making any change to an exempt study to submit a request to modify the submission, so that the board can confirm the change has not altered the regulatory status of the activity. The logic is straightforward: exemption was granted on the basis of what the activity was, and a change to the activity can quietly move it out of the category it was exempted under.
For participants already enrolled, SOP 305 places the duty on the investigator to re-consent them where the board determines the change requires it, and the guidance sheet notes the board may require re-consent where an amendment affects participation or risk. Plan for that possibility when you draft the change, because a re-consent obligation discovered after approval means going back to people who have already given you their time.
What to do next
Before you change anything, write the change down as a sentence and ask three questions of it: does it touch procedures, recruitment, consent, risk, benefit or the participant's experience; does it alter the enrolment figure or the medium; and does it change what the study is asking. The first two put you in the amendment packet. The third puts you in a new protocol. Then walk every document that carries the affected dimension before you draft the form.
If you would rather not carry it yourself, this practice handles the whole post-approval loop — the amendment drawn across every document, the tracked copies, the submission, and every reply until the change is approved. Ask for the free review and send the approved file plus the change you have in mind; what comes back is a written finding on whether it waits, and what it will take. How it works sets out the sequence, and the FAQ answers the short questions.
Sources
- PG IRB SOP 305: Amendment Requests
- PG IRB Amendment Guidance Sheet
- PG IRB Worksheet IRB-314: Criteria for Approval
- Purdue University Global IRB — Investigator Guide (proposal and post-approval request forms)
- Purdue University Global IRB — Toolkit
- 45 CFR Part 46 — Protection of Human Subjects (govinfo)