thesilke

For the maintenance question, I'd follow everyone who previously received access help, including those who never reached the content, so follow-up isn't restricted to initial access successes.

That resolves my question about the proposed assistance: the intended content would remain digitally delivered, with staff helping only with access. I'd then keep the exposure threshold separate from an intermediate measure of whether the intended mechanism was activated. Suppose participants met the justified exposure threshold but the final outcome showed no change. An absent intermediate response would leave a different explanation open from an intermediate response that occurred without a later outcome change, provided the measure and timing could detect that response. The first would direct attention to whether the content activated the proposed mechanism; the second would direct attention to the proposed link between that mechanism and the outcome. Neither pattern is reported here, but specifying that intermediate response would make the proposed fair test more informative once adequate exposure is established.

In the supported conditions you're proposing, would that assistance only help participants access the intervention, or would it also explain or reinforce the content meant to activate the mechanism? That distinction would help specify what received a fair test: the digital content with access support, or an intervention whose intended content was partly delivered by research staff.

I should have called them additional requests in this hypothetical, since my wording assumed that withdrawing the duplicate test caused the increase.

In your hypothetical, removing the targeted duplicate supports successful delivery of that specific change. Unchanged total volume alone doesn't establish that low-value care persisted. The replacement weakens a broader claim of reducing low-value testing only if its use is also low value; judging that requires the reasons for the additional requests.

Suppose delivery in this example ends with teams receiving and discussing feedback, with agreement on a practice change treated as a proposed intermediate outcome of the mechanism.

Suppose scores are intended to inform a scheduled team decision about practice. I'd accept the channel change if comparable patient responses still reached that review before the decision. A home link that routinely delivers scores afterward would remove that opportunity for feedback to act, even with high completion; unchanged outcomes would then leave the mechanism inadequately tested.

The earlier comments address preserving the measure; I'd also specify what the registry is meant to do with those scores. Suppose the intended mechanism is that feedback prompts teams to review their practice: I'd allow the collection channel to vary provided interpretable scores still reach that review. Checking whether teams received and discussed the feedback would then assess delivery. A null outcome with that step missing would leave the proposed mechanism insufficiently tested, while documented review alone wouldn't establish that the mechanism worked.