And the data that prevents the four that cost real money.
Every few years, a school business official who spends most of the year on levies, transportation contracts, and budget amendments gets handed one of the highest-dollar, multi-year decisions the district will ever make: the teacher contract. Across the table sits a team that does this constantly, with comparables and cost figures ready.
Illinois school attorneys have a well-worn list of the mistakes that hurt districts most in that room. Four of them come down to one thing — not having your own numbers. Here is the full list, and where the data does the heavy lifting.
The ten mistakes
- Lacking clear-cut goals and priorities from the outset.
- Prematurely making your best offer — or prematurely accepting theirs.
- Not knowing in advance the exact cost of any proposal.
- Relying on the other side's documentation and facts without checking them.
- Not being prepared with better alternatives to the proposals you can predict.
- Focusing on the union's demands instead of your own priorities.
- Regressive bargaining — moving backward from an offer already on the table.
- Rushing the process.
- Failing to plan for public relations.
- Becoming emotional and losing objectivity.
Numbers 1, 2, 6, 8, 9, and 10 are about discipline and preparation — they're on you and your team. But four of them — 3, 4, 5, and 7 — are really about one thing: do you have independent, accurate numbers before you walk in? That's where most of the avoidable money is lost.
Mistake #3: Not knowing the exact cost of any proposal
This is the costliest one, because it compounds. You cannot evaluate a salary proposal — yours or theirs — without knowing how many teachers sit at each step and lane of your schedule. A 2% increase costs one number for a young, bottom-loaded staff and a very different number for a topped-out one. Add automatic step movement (typically 1.5–3% of payroll on its own, before any negotiated raise), lane movement, and benefit trend, and the "real" cost of a contract is routinely well above the headline percentage.
The fix is to cost every proposal against your actual staff distribution — your scattergram — and to model all the cost drivers separately so you can see exactly where the growth comes from. When you can say "that proposal is 3.1% on the schedule but 4.6% in new money once step movement is counted," you've changed the conversation.
Mistake #4: Relying on the other side's facts
When the union's team presents comparables — "here's what the districts around us settled for" — those numbers are selected to make a case. That doesn't make them wrong, but it makes them theirs. Walking in without your own settlement data means negotiating on a field the other side drew.
The fix is to bring your own comparables, built from the same public record everyone can verify: ISBE's Teacher Salary Study and the actual settlements districts have filed and reported. When both sides reference a neutral source, the argument shifts from "whose numbers" to "what they mean" — which is where a prepared district wins.
Mistake #5: No better alternative to a predictable proposal
Most union opening proposals are predictable in shape. If you know the regional settlement pattern — what comparable districts actually agreed to over the last few cycles — you can prepare a credible counter before the first session. Without that history, you're reacting; with it, you're anchoring.
Mistake #7: Regressive bargaining (and how data prevents it)
Regressive bargaining — appearing to move backward from a position already on the table — can be an unfair labor practice, and it poisons trust. It usually happens by accident, when a team makes an offer before it has fully costed the implications, then has to walk it back. The cure is preparation: know your end point before you make your first offer, and you'll never have to retreat. That requires costing the whole package — salary and insurance together — before you open.
The thread running through all four
Mistakes 3, 4, 5, and 7 are the same mistake wearing four hats: showing up without your own verified numbers. The district that walks in with its scattergram built, every proposal pre-costed, and regional comparables sourced from the public record doesn't just avoid four expensive errors — it changes who sets the terms of the conversation.
That's the entire reason CollBar exists. Eleven years of settlement history for every Illinois district, drawn from ISBE Teacher Salary Study and EIS records, filtered to your enrollment, county, and district type — plus a free toolkit that turns your own contract into a three-year cost model. You bring your numbers; the union brings theirs; the public record settles it.
See your district's data free at CollBar.
Source data: Illinois State Board of Education (Teacher Salary Study, EIS), obtained as public records. CollBar is an independent tool and is not affiliated with or endorsed by ISBE. This article is general information, not legal advice; consult your board attorney on bargaining strategy and labor law.
