Valuation date
The valuation date is the specific date as of which your claims are priced for your experience rating. A claim still open on the valuation date is counted at its reserve, the carrier's current estimate of total cost, not at what's actually been paid by that date. This is why the reserve matters so much more than the payment history for any claim that's still open: your EMR (experience modification rate) is built using whatever the carrier's file says the claim is worth on that one date, whether or not that estimate turns out to be accurate. A reserve that's too high on the valuation date inflates your mod for the rating that uses that date, even if the claim later resolves for far less. Checking that every open claim's reserve is current and accurate before your next valuation date locks it in is one of the highest-value things you can do to catch an error before it counts against you.
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Source
Is your mod right?
Most contractors have never had the worksheet compared to the loss runs and payroll behind it. See what your mod is costing you, or get on the list for a full verification.