Methodology

Methodology and data caveats

How every figure on this site, including the dollar amounts, is defined and computed, and the limits of the underlying CMS data.

Source and unit

Source: the CMS Federal IDR public use files (PUF), “OON Emergency & Non-Emergency” file, reporting quarters 2023 Q1 through 2025 Q4 (12 quarters; 8,233,903 line items in total). Air ambulance disputes are out of scope. See data sources.

The unit is the dispute line item (one row in the CMS file). One dispute can contain many line items. A quarter is the CMS PUF reporting quarter as labelled by CMS.

Definitions

Determined line item

A line item whose “Payment Determination Outcome” is in favor of the provider/facility or in favor of the plan/issuer. Of 8,233,903 line items, 8,226,328 are determined; 7,459 are split decisions and the rest have a blank or unrecognised outcome.

Provider win rate

Provider-favored line items ÷ (provider-favored + plan-favored line items). Split decisions are excluded from the denominator, as are blank/unknown outcomes. Default decisions are included (CMS: a party that failed to submit an offer or pay fees loses by default). CMS reports the outcome at the dispute level (the party that prevailed in the majority of line items), so each line item carries its dispute’s outcome.

Payment-to-QPA ratio

The CMS field “Prevailing Party Offer as % of QPA”: the selected offer divided by the qualifying payment amount, shown as a multiple (1.00x = the QPA). Computed on determined line items with a non-suppressed value; blank, “N/A”, “NR” and “+” values are dropped, so the ratio n is usually lower than the win-rate n. 2024 Q3–Q4 files store this field as percent strings (e.g. “1,014%”), which we convert to 10.14x. We report the median and the 25th and 75th percentiles (linear interpolation). Means are not shown because a few extreme ratios dominate them.

Days to decision

The CMS field “Length of Time to Make Determination”, in business days, median over determined line items. CMS changed the definition: in the 2023 and 2024 files it runs from assignment of the certified IDR entity to closure; in the 2025 files it runs from dispute initiation to closure (CMS reports the average difference as 3.1 to 4 business days per 2025 quarter). Years are therefore shown separately and never pooled.

State

The CMS field “Location of Service”, the state where the item or service was provided (place of service), not where the provider is located. Texas figures mean services provided in Texas. Line items with a missing or non-state value (for example “N/R”) count in all-state figures only.

Payer

The CMS field “Health Plan/Issuer Email Domain” (lower-cased). The label shows the most common “Health Plan/Issuer Name” reported with that domain. Plan names are reported by the initiating party and are inconsistent, so we key on the domain. Some domains belong to vendors or administrators acting for plans, not to the plan itself. Only domains with at least 30 determined line items are selectable (467 domains); all others count in all-payer figures.

CPT code

The CMS “Service Code” on line items where CMS’s “Type of Service Code” is CPT. HCPCS, DRG and untyped codes count in all-code figures but cannot be selected individually. 1,910 CPT codes have at least 30 determined line items and are selectable.

Specialty

CMS publishes “Practice/Facility Specialty or Type” as free text typed by the provider (more than 8,000 distinct labels, including typos and organisation names). We assign each label to a specialty group using the rules below. This grouping is ours, not a CMS classification.

Minimum n and rounding

A figure is shown only when at least 30 line items stand behind it; static pages exist only for states, specialties, state–specialty pairs and CPT codes with at least 30 determined line items over 2023 Q1–2025 Q4. Win rates are rounded to 0.1 percentage point and ratios to 0.01x (nearest value). Every figure is precomputed exactly from line-item data; the browser does not estimate anything.

Dollar amounts

Dollar figures come from a different CMS file than everything else on this site: the “QPA and Offers” file of each quarterly PUF, which lists the QPA, both offers and the prevailing offer in dollars for each line item. We use it for 2024 Q3 through 2025 Q4 only (six quarters). Before 2024 Q3 that file has no “Type of Service Code” column, so the Excel code damage described under caveats cannot be repaired there; for 2023 Q1–2024 Q2 every dollar figure is shown as not available. We never estimate a missing figure.

Line items with dollar amounts (n)

Rows of the QPA and Offers file decided in favor of the provider/facility or the plan/issuer whose QPA and prevailing offer are both numeric, with a QPA above $0. Suppressed values (“^”, “+”), “N/A” and “N/R” are dropped, and air ambulance rows are removed. In 2024 Q3–2025 Q4 this leaves 5,594,409 line items.

Total awarded

The sum of the prevailing (selected) offers. This is what the IDR entity chose, not what was eventually paid; collection is not in the CMS data.

Total QPA

The sum of the QPAs of the same line items.

Awarded above QPA

Total awarded minus total QPA (a net figure: awards below the QPA reduce it).

Median and mean award per line item

The median and the mean of the prevailing offer, in dollars, per line item.

Median QPA

The median QPA per line item, in dollars.

Award vs QPA, dollar-weighted

Total awarded ÷ total QPA (an offer-weighted ratio). Large line items count for more than in the per-line median ratio shown elsewhere, so the two can differ noticeably.

State

The file has no “Location of Service”; it has a “Geographical Region” (a metro area or state label, for example “Dallas-Fort Worth-Arlington, TX”). We assign each line item to every state named in its region, so a metro area spanning states (for example “Texarkana, TX-AR”) counts in each of them; national totals count every line item once. Regions reported as “N/R” count only nationally.

CPT code

“Service Code” where “Type of Service Code” is CPT, with the same zero-padding repair as the main file.

Minimum n and rounding

A dollar figure is shown only with at least 30 line items behind it. Totals are rounded to $0.1 million (or to the dollar below $1 million), per-line amounts to the dollar, ratios to 0.01x.

Limits. The QPA and Offers file has no dispute number, specialty, payer or provider field, so it cannot be joined to the line items behind the win rates, and dollar figures cannot be cut by specialty or payer; those selections show not available. Its line item counts therefore differ from the counts beside the win rates. 2025 Q1–Q2 files are the January 21, 2026 release.

Check. For Texas anesthesia (CPT 00100–01999, regions naming TX), 2025 Q1–Q4: 61,062 line items, total awarded $146.4M against $36.4M in QPAs, a dollar-weighted 4.02x. Our build recomputes this figure on every run.

Specialty grouping rules

The label is upper-cased and trimmed, then tested against these patterns in order; the first match wins. Labels matching nothing go to “Other / unclassified labels”. Patterns are regular expressions.

Note: these groups are based on the self-reported label, so “Anesthesiology” here is not the same as a CPT-based anesthesia cut (CPT 00100–01999). Use the CPT selector for code-based questions.

Data caveats

1. Excel code mangling, 2023 Q3–2024 Q2. These quarters were published as Excel workbooks in which numeric service codes lost their leading zeros (for example anesthesia CPT 00813 stored as 813). A naive filter finds no anesthesia codes in those quarters. We repaired CPT-typed codes with a 3–4 digit value between 100 and 1999 by zero-padding to five digits. Repaired line items per quarter:

   Quarter	Codes repaired
   2023Q1	6
   2023Q3	2,560
   2023Q4	4,095
   2024Q1	10,753
   2024Q2	18,826

   Other code values altered by Excel, if any, could not be detected or repaired.
2. Dollar figures only from 2024 Q3. Dollar amounts and the dollar-weighted ratio need the separate “QPA and Offers” file, which has no code-type column before 2024 Q3, so the same code mangling cannot be repaired there. Dollar figures for 2023 Q1–2024 Q2 are therefore not available (see dollar amounts).
3. Early volume is thin, especially in Texas. The PUF grew sharply over time, so pooled 2023–2025 figures are dominated by 2025 and early years are not directly comparable. Texas (place of service), all specialties, determined line items:

   Period	n determined
   2023 Q1–Q4	98,957
   2024 Q1–Q4	826,916
   2025 Q1–Q4	2,535,325

   Narrower Texas cuts (single specialties or codes) are thinner still in 2023 and early 2024.
4. Default decisions are included in win rates and ratios. They are decisions in which one party did not participate, so they can raise or lower a win rate relative to contested cases.
5. Withdrawn, settled and ineligible disputes are not in the data. The PUF covers payment determinations only. Win rates describe disputes that reached a decision, not the share of all disputes or claims that end in a provider’s favor.
6. Days definition changed in 2025 (see above); days are never pooled across years.
7. Outcome is dispute-level. In a batched dispute, every line item carries the dispute’s majority outcome, even if a particular line item’s offer was not the one selected.
8. Duplicates. A small number of line item numbers appear in more than one quarterly file. They are kept, as CMS published them.
9. Release vintages. 2023 Q1–Q2 files are the February 15, 2024 release, 2024 Q1 the March 18, 2025 re-release, and 2025 Q1–Q2 the January 21, 2026 release, as named in the files. CMS later updated files; figures reflect the copies listed on the data sources page.
10. Very high ratios (†). Some cuts show median ratios of 20x the QPA or more. These come straight from the CMS field but may reflect very low or mis-entered QPAs or unit differences in the CMS data. Medians at or above 20x are marked †; treat them with caution.
11. Not a prediction. These are descriptive statistics of past determinations. They do not predict the outcome or payment of any dispute and are not legal or financial advice.