The consultant who shows up four days a week costs less than the full-time guy but still expects the salary band

You're right that the "compressed expertise" problem is real, but I think you're bundling two different failure modes that don't always happen together. The electrical contractor case is solid—that's apprenticeship knowledge, and yeah, you can't Slack someone a code update and have them weight it correctly against their mental model of what inspectors in their county care about. But a fractional CFO doing month-end close is actually a different animal. The decision tree *is* mostly documented. The micro-observations matter less when the work is repeatable and the stakes for getting it wrong are just "we close slower" instead of "we picked the wrong wire gauge and now there's a liability issue." Where I'd push back on your framing: the value isn't that it's fractional. The value—when it exists—is that you don't need someone in the seat full-time and pretending they do. I spent five years watching operations managers spend 15 hours a week on actual work and 25 hours in meetings defending why they needed to exist. Some roles have a legitimate four-day floor. Others don't. The problem is we almost never distinguish between those two categories before hiring, so we end up either overstaffing chronically or underselling someone's time while pretending it's a clean arrangement. You're right that those are the actual failure modes. But that's an indictment of how we assess what a role actually requires, not necessarily of fractional work itself.

I'd push back on the "you can't compress expertise" claim a bit, but not in the way you might expect. The issue isn't that expertise can't work part-time—it's that we're usually measuring the wrong things. I worked with a federal immigration judge for three years who also did pro bono asylum appeals two days a week. Those pro bono days? She caught things in her paid work she'd have missed otherwise. The constraints forced her to be more systematic. She had to write everything down. When you're not there every day drowning in motion dockets, you notice when a pattern contradicts itself. I'm not saying this scales to electrical code—there's real domain-specific accrual happening there. But I've also seen "full-time expert" mean someone who's deep in local noise and assumption, and a thoughtful outsider four days a week actually sees the forest better. The real problem is that we price fractional roles like they're just the daily rate times 0.6, when the actual value (or lack of it) depends entirely on whether the *discontinuity* itself becomes the bottleneck. In the judge's case, it didn't because cases don't move that fast anyway. But put that same person in a role where decisions need to happen across a continuous five-day cycle and yeah, you've built in friction. That's not a feature of part-time work, though—that's just bad job design meeting bad scheduling.

I managed supply chain for an apparel manufacturer that tried this with a part-time quality director. Guy had thirty years in textiles, charged consultant rates, committed to three days a week. On paper it looked efficient—we had the expertise without the full salary. What actually happened: a batch of fabric came in with a dye lot mismatch that should've been caught at receiving. It sat for four days because he wasn't there, got cut, got sewn, then we found it. By then we'd already tagged it for a major retailer. The fix cost us thirty grand and we ate it because the timeline was our problem. A full-time person would've seen it Tuesday morning. The thing about quality control—or most manufacturing decisions that actually matter—is that they're not episodic. They're continuous. You need someone there when the variance happens, not someone you can brief on Monday about what to watch for. Same with supply chain. The value of having someone on-site three days isn't 60% of having them five days. Some decisions just get deferred or made worse because the person isn't there when the decision needs making. It can work if the role is truly advisory and low-frequency. If you need someone to show up quarterly, audit something, and leave, fine. But if you're expecting real-time judgment calls and you're hiring someone part-time to save money—you're not really hiring someone, you're hiring their occasional availability and hoping nothing urgent happens on a Wednesday.

I'd push back on the stability assumption here. I ran into a case that actually worked, but it only worked because of how the role was structured, not despite the fractional piece. We had a transit authority that brought in a part-time service planning consultant—three days a week, explicit scope, for about two years. The key constraint was that service planning in that system didn't require real-time decision-making the way your electrical inspector does. We had quarterly service change windows. Everything got planned, modeled, tested in advance. The consultant came in, did the analysis, made recommendations, then stepped back. The institutional knowledge she built got embedded into the process and the spreadsheets before she left—it had to be, because she wasn't there to fill the gap with presence. But here's the thing: that only worked because we were ruthless about what didn't need her. Operations questions, driver scheduling disputes, the thousand micro-observations you're talking about? Those stayed with the permanent operations team. She wasn't a fractional operations manager pretending to be full-time. She was a consultant doing a bounded project that happened to stretch across quarters. Most fractional executive arrangements I've seen do exactly what you're describing—they're trying to get full-time judgment in a three-day-a-week package because the company doesn't want to commit to headcount. The difference is whether the role actually has a discrete output (plan gets built, decision gets made) or whether it's just "be the person who knows things" compressed into a schedule that can't support knowing things. One's a gig. The other's slow-motion failure with a nicer title.