What plan design is worth
Plan design transfers cost. Purchasing reduces it. Three tools to run against your own plan, with nothing stored.
This page collects the interactive tools from Just a tree in one place, and adds one that the article does not carry. Everything here runs in your browser against numbers you type in. Nothing is uploaded, nothing is saved, and nothing asks for your email.
Two different jobs
Plan design is a risk transfer tool. Moving a deductible or a copay does not change what a knee replacement costs. It changes how much of the cost, and how much of the risk, shifts from the plan to the employee.
Reducing what the plan spends is procurement. What you buy, where you buy it, and what you agree to pay, the same way the business buys everything else.
The first two tools show where the transfer runs out of room. The third prices it.
A suggestion before you start: these work best with your actual plan in front of you. A summary of benefits, last renewal's rate page, and ten minutes will get you further than an afternoon of reading commentary, mine included.
1. Where your cost sharing stops
Enter your deductible, your coinsurance, and your out of pocket maximum, or load a national benchmark with one of the preset buttons. The tool returns the claim size at which member cost sharing is fully exhausted, the point where every additional dollar belongs to the plan. On the average large-firm plan that point arrives near $23,000. The number to sit with is what share of your spend lands above yours.
A chart showing the share of a claim borne by the member as claim size grows. Cost sharing applies fully at small claims, then collapses toward zero once the out-of-pocket maximum is reached, which happens well below the claim sizes that drive most plan spending.
Where plan design stops working
Cost sharing is a lever with a hard stop. Past the out-of-pocket maximum, the plan pays every additional dollar and deductible design has no further effect. Enter your plan to find the stop.
Your plan design stops mattering above
$23,320
| A claim of | Member pays | Plan pays | Member share |
|---|
What a typical employer plan looks like
2. The claims your plan likely sees
The same claim sizes, drawn as a population. Start by picking your funding ecosystem, since what a plan can influence depends on who holds the contracts. Then hover or tap any marker: each one tells you where the number came from, how much a plan can typically influence it, and roughly how many dollars that influence is worth on one case. Color is influence, size is dollars, and a big claim with a small dot is money you can see and cannot reach.
Share of people spending at least a given amount per year, with each reference point rated for how much a plan can influence it under two funding models.
Start here: pick your funding ecosystem
3. What a design change is actually worth
This is the addition, and for most readers it will be the useful one. Enter your current design in one column and the alternative you are weighing in the other. The tool returns the actuarial value of each, the difference between them, and a premium estimate for the move, decomposed so you can see what the fixed costs of the arrangement keep from you.
If you are running a midyear review or weighing renewal alternatives, this is built to sit beside that conversation. Model the deductible bump before the meeting and you will generally find it is worth less than the room assumes.
One thing this tool does on purpose: it does not model copay tiers in fine detail. The precision matches the size of the effect. Copay-level changes move the plan's economics so little that modeling them finely would only decorate a rounding error. If you want design changes members actually feel, the leverage generally runs the other way, toward targeted improvements. Richer physical therapy benefits that support surgical avoidance, $0 generics that support adherence, account funding that buys value without touching the medical rate. Those are the design conversations worth an hour, and this tool will at least show you what the traditional ones are worth first.
What a plan design change is actually worth
What a design change is actually worth
Enter the plan you have on the left and the one you are weighing on the right. This is a directional model, not a quote and not an actuarial opinion. It is built to size a change before the renewal meeting, so you walk in knowing roughly what the move is worth. Your own claims, your own underwriting, and your own carrier's rating will differ. Everything runs in your browser and nothing is stored. Money inputs are monthly except account funding, which is annual.
Current plan
Alternative
Assumptions and premium inputs
Actuarial value is computed by integrating member cost sharing over a claims distribution fitted to four public anchors: 12% of covered members with no claim, 44% under $1,000, 15% at $10,000 or more, and a mean of about $6,700, from KFF analysis of Merative MarketScan, with the million-dollar claim rate from Sun Life's 2026 stop-loss report. Induced utilization factors are 1.00, 1.03, 1.08 and 1.15 by metal tier, from the CMS Summary Report on Permanent Risk Adjustment Transfers for the 2024 Benefit Year. The fixed-cost share defaults to 15%, which is the retention assumption for a fully insured large group. This models a single member in a single plan year, in network, and ignores copay-only services and separate pharmacy accumulators.
Current AV
74.8%
Alternative AV
69.7%
Change
-5.1 pts
| What moves the premium | Per month | Per year |
|---|---|---|
| If the whole premium moved with actuarial value | ||
| What survives the fixed-cost floor | ||
| Induced utilization effect | ||
| Estimated premium change |
| Where the member lands | Current | Alternative |
|---|---|---|
| Cost sharing stops at a claim of | ||
| Average member cost sharing per year | ||
| Plan liability AV, before account funding |
Two actuarial values are reported and they answer different questions. Total AV is net of employer account funding and is the figure comparable to a metal tier. Plan liability AV is gross of it and is what drives the premium, because account dollars buy value without moving the medical rate. Modeled results describe what the fitted distribution implies, not what any particular plan will achieve. Not actuarial advice.
Where the argument lives
The tools stand on their own, but they were built to carry an argument, and the argument lives in Just a tree: where plan design stops reaching, where the money actually sits, and why the same small move keeps getting made anyway. If a number here surprises you, that piece is where the sourcing and the reasoning are.
Figures and benchmarks are drawn from published sources cited within each tool. Modeled results describe what published differentials imply, not what any particular plan will achieve. Fringe Theory is independent and unaffiliated. Views expressed are my own and do not represent those of my employer. Nothing here is legal, tax, medical, or investment advice.