Reading a Protocol for Recruitment Risk Before You Sign

Most conversations about protocol complexity focus on eligibility criteria — the twenty-line inclusion list that shrinks your pool. That matters, but it isn't where sites get hurt most. The bigger damage usually shows up after someone qualifies: in consent conversations that stall, in screen failures at week two, and in withdrawals from people who were genuinely willing until they saw what the schedule actually asked of them.

Complexity is a recruitment problem, not just an operations problem. Here's how to read it that way.

Where complexity actually costs you patients

Visit burden per unit of benefit. A patient does rough math during consent: how many hours, how many trips, how much discomfort, for what. Twelve visits over six months for a condition causing daily symptoms is an easy sell. Twelve visits for a preventive indication in an asymptomatic population is a hard one. The absolute number matters less than the ratio.

Procedures people decline individually. Optional sub-studies, biopsies, lumbar punctures, extended PK days, imaging with contrast. In most site datasets, one or two procedures account for a disproportionate share of consent-stage drop-off. Identify them before activation, not after.

Washout and lifestyle requirements. Asking someone to stop a medication that's working, or to abstain from alcohol for the duration, quietly disqualifies people who technically meet criteria. They screen as eligible and then decline. That looks like poor recruitment; it's actually protocol design.

Caregiver or partner requirements. Any protocol needing a study partner effectively doubles the recruitment task. You're enrolling two people, and the second one has no clinical motivation.

What to do at feasibility

Read the schedule of assessments before you read the synopsis. Then work through this:

1. Time-map one full participant journey. Add up door-to-door hours including travel, per visit, across the whole study. Total that number. If it exceeds what a working adult can absorb without taking PTO, say so in feasibility.
2. Flag the single worst visit. Every protocol has one — the eight-hour PK day, the double-scan visit. Ask whether it can be split or whether meals and parking are covered.
3. Check the washout against your actual patient population. Not the general population. Pull a chart review if you can.
4. Count how many things must be true simultaneously. Eligibility criteria interact. Three individually reasonable criteria can combine into something nearly impossible in practice.
5. Ask what's required versus what's collected. Sponsors sometimes have flexibility on optional assessments that nobody mentions unless a site asks.

Managing complexity you can't change

Once you're activated, the protocol is what it is. Your leverage moves to disclosure and support.

Be fully transparent early. Present the heaviest visit during the first conversation, not at consent signing. Sites that front-load the hard parts commonly see slower consent rates and much better retention — which is the trade you want. Someone who withdraws at week eight cost you a screening slot, staff hours, and a data point.

Build visit-day support around the burden: schedule long visits early in the week, arrange transport proactively, tell people exactly what to bring and how long they'll be there. Give participants a printed calendar of every visit at enrollment.

And track your own numbers by protocol. If consent-to-randomization conversion drops sharply on complex studies, that's evidence — bring it to your next feasibility conversation with the same sponsor.