Why Damages Allocation results differ in Illinois

The top 5 reasons results differ

Run this scenario in DocketMath using the Damages Allocation calculator.

If you run the Damages Allocation calculator in DocketMath for Illinois matters, you may notice allocation outputs that don’t match across datasets or versions. In Illinois, the mismatch usually comes from a small set of repeatable variables—especially when the tool is pairing time windows to damages.

Below are the top five reasons Illinois results differ, even when the same parties are involved.

A key Illinois anchor for this analysis: Illinois’ general statute of limitations is 5 years under 720 ILCS 5/3-6. When no claim-type-specific sub-rule is found or selected, DocketMath uses this general/default period to set the lookback window.

• General SOL Period: 5 years
• General Statute: 720 ILCS 5/3-6
• Source: https://ilga.gov/ftp/Public%20Acts/101/101-0130.htm?utm_source=openai
• Rule-selection note: No claim-type-specific sub-rule was found for this setup, so the general/default period is the rule in these runs.

Practical takeaway: If one run used the general/default 5-year SOL (720 ILCS 5/3-6) and another run used a different time window (or a claim-type-specific shortcut), the allocation will predictably diverge—even if all other inputs match.

How to isolate the variable

Use this checklist to pinpoint why two DocketMath outputs don’t reconcile.

• Freeze the jurisdiction and tool settings so both runs use the same rule set.
• Compare one input at a time (dates, rates, amounts) and re-run after each change.
• Review the breakdown to see which segment or assumption drives the difference.

1) Lock the jurisdiction and confirm the time rule

In your DocketMath run, confirm you’re using US-IL and the default SOL behavior:

• Rule applied: General/default 5-year SOL (720 ILCS 5/3-6)
• No claim-type-specific sub-rule: meaning the model uses the general period

If you see a lookback window other than 5 years, you’ve found the first likely cause.

2) Compare the exact dates used to compute the lookback

Even small date shifts matter. Focus on:

• Incident / damage start date
• Filing / valuation cut-off date
• Any “event” date chosen during import or mapping

Then verify both runs compute the same number of months/years falling inside the 5-year window.

3) Normalize the damages inputs

Create a “diff view” of your line items:

• Total damages per category
• Any withheld / blank categories
• Whether “unknown” values were treated as zero vs. excluded

A single missing line item can change the denominator used for allocation, which changes the split even if the overall picture looks similar.

4) Verify allocation method settings

If your runs used different toggles (for example, proportional vs. weighted allocation), totals may look close while splits diverge. Lock the method and rerun.

5) Confirm the tool run configuration is identical

Reconcile:

• Jurisdiction selection (US-IL)
• The damages-allocation calculator configuration/version
• Any imported assumptions (especially date-field mapping to the calculator’s expected fields)

For a consistent starting point, use the primary CTA: /tools/damages-allocation.

Next steps

1. Re-run with a controlled test case
   Keep everything constant except one variable (date mapping, SOL window behavior, or allocation method). Record how the output changes.

2. Create a two-run comparison sheet
   One row per run:

   • Lookback window start/end
   • Total allocable damages
   • Split by category

3. Validate the Illinois time rule once, then stop guessing
   Illinois general SOL is 5 years under 720 ILCS 5/3-6—and when no claim-type-specific sub-rule is found, that general/default period governs the time window.

4. If disagreement persists, audit the mapping
   Most “mysterious” differences turn out to be:

   • date-field mapping (incident date mapped to filing date, etc.)
   • category exclusions introduced by the dataset import

Related reading

• Damages Allocation Guide for Alabama — Comparative Fault Rules
• Damages Allocation Guide for Alaska — Comparative Fault Rules
• Damages Allocation Guide for American Samoa — Comparative Fault Rules