RCM glossary

The average number of days it takes a practice to convert a billed charge into cash.

Calculated as total accounts receivable divided by average daily charges, usually over a trailing three-month window. It is the single most quoted revenue cycle metric because it compresses payer speed, claim quality, and follow-up discipline into one number.

A falling number is only good news if A/R over 90 days is falling with it. Writing off aged balances lowers days in A/R without collecting a dollar.

A/R over 90 daysNet collection rateFirst-pass resolution rate

The share of outstanding receivables that has been unpaid for more than 90 days from the date of service or billing.

Reported as a percentage of total A/R. It is the aging bucket that predicts write-offs, because appeal windows and timely-filing limits start closing past this point.

Measure it consistently from either date of service or date of first billing — mixing the two across reports makes trend lines meaningless.

Days in A/RTimely filing limitWrite-off

The percentage of collectible revenue actually collected, after contractual adjustments are removed.

Payments divided by charges minus contractual adjustments. Unlike gross collection rate, it measures performance against what the contracts actually allow, so it isolates the revenue lost to denials, underpayments, and abandoned follow-up.

Gross collection rate mostly reflects your fee schedule, not your billing performance. Net collection rate is the one to manage.

Days in A/RUnderpaymentWrite-off

A claim paid below the contracted allowable for the service.

Detected by comparing line-level payments against the loaded fee schedule. Because the claim shows as paid, underpayments do not appear in denial reporting and are rarely worked without an automated comparison.

This requires current contracted rates loaded in the system. Without them, underpayment recovery is guesswork.

Net collection rateERA and EFT

Removing a balance from accounts receivable, either contractually or as uncollectible.

Contractual write-offs are the expected difference between charge and allowable. Administrative write-offs — timely filing, missing authorization, unappealed denials — represent revenue that was earned and lost.

Report the two separately. Combining them hides the only category you can actually reduce.

Net collection rateTimely filing limitBad debt

The percentage of claims paid on the first submission with no edit, rejection, appeal, or rework.

Measured against claims submitted in a period, not claims adjudicated. It is the cleanest proxy for front-end discipline: eligibility, authorization, demographics, and coding accuracy all show up here before they show up in A/R.

Clean claim rate is sometimes defined as claims that pass clearinghouse edits, which is a weaker test than being paid. Confirm which definition a vendor is quoting.

ClearinghouseClaim scrubbingDenial rate

An intermediary that validates, formats, and routes electronic claims between a practice and its payers.

Claims are checked against payer-specific edits, converted to the required electronic format, and delivered with acknowledgement reports. Rejections at this stage never reach the payer, so they are not denials and do not appear in denial reporting.

Unworked clearinghouse rejection reports are a common hidden cause of aged A/R: the practice believes a claim is pending when the payer never received it.

Rejection vs. denialClaim scrubbingERA and EFT

Automated pre-submission checking of a claim against coding, payer, and data-integrity rules.

Scrubbing catches missing modifiers, invalid code pairings, demographic mismatches, and coverage problems before the claim leaves the practice. It is the highest-leverage control available because prevention costs a fraction of an appeal.

First-pass resolution rateNCCI editsModifier

The electronic explanation of how a claim was adjudicated, and the electronic deposit of the payment.

The ERA carries line-level allowed amounts, adjustments, and reason codes that drive posting and denial work. EFT moves the money.

Posting from a bank deposit rather than the ERA loses the reason codes, which is how denial trends go unnoticed for months.

CARC and RARCUnderpayment

A rejection is a claim refused before adjudication; a denial is a claim adjudicated and refused payment.

Rejections come from a clearinghouse or a payer front end for format or eligibility data problems and can usually be corrected and resubmitted. Denials have been processed, carry a reason code and an appeal window, and often require documentation to overturn.

Counting rejections inside your denial rate inflates it and hides which problem you actually have.

Denial rateCARC and RARCClearinghouse

The percentage of submitted claims that a payer adjudicates and refuses to pay.

Best tracked two ways at once: by count, which shows workload, and by dollars, which shows exposure. Segmenting by payer and reason code is what turns the metric into a work plan.

A denial rate with no reason-code breakdown cannot be improved, only reported.

CARC and RARCRejection vs. denialAppeal

Standardized codes on a remittance that explain why a payment was adjusted and add supporting detail.

The CARC gives the reason for the adjustment; the RARC adds the specific circumstance. Together they are the only reliable basis for grouping denials into preventable and non-preventable categories.

Group by CARC family before assigning ownership. Eligibility denials belong to the front desk; medical-necessity denials belong to coding and clinical documentation.

Denial rateAppealERA and EFT

A formal request for a payer to reconsider a denied or underpaid claim, filed within a defined window.

Levels, deadlines, and required documentation vary by payer and plan type. A first-level appeal is often a corrected claim or a records submission; later levels may require peer review or an external reviewer.

Appeal windows are shorter than timely-filing windows on many plans. Log the deadline the day the denial posts, not the day the work starts.

Denial rateTimely filing limitCARC and RARC

The deadline by which a payer must receive a claim for it to be considered at all.

Runs from the date of service or, for secondary claims, from the primary's remittance date. A timely-filing denial is generally not appealable on the merits of the service.

This is the deadline that converts aged A/R into a permanent write-off. It is why the over-90 bucket matters more than the average.

A/R over 90 daysAppealWrite-off

A payer's determination that a service was appropriate and required for the patient's condition.

Established through the diagnosis reported, the documentation in the note, and any applicable coverage policy. Denials here are clinical-documentation problems, not coding problems, and are corrected upstream in the note rather than downstream in the claim.

LCD and NCDMedical decision making (MDM)Modifier

The complexity framework used to select an office or outpatient visit level.

Assessed on the number and complexity of problems addressed, the amount and complexity of data reviewed, and the risk of complications from management. Visit level can alternatively be selected on total time on the date of the encounter.

Choosing a level on time alone, without documenting what the time included, is the most common audit finding on level-4 visits.

Medical necessityUpcoding and downcoding992139921499215

A two-character suffix that changes how a payer interprets a procedure code without changing the code itself.

Modifiers communicate circumstances such as a separately identifiable service, a distinct procedural service, or delivery by telehealth. They are also the most frequently misapplied element of a claim.

NCCI editsUpcoding and downcodingModifier 25Modifier 59Modifier 95

CMS-published rules defining which procedure codes may not be billed together, and when a modifier can override the pairing.

Procedure-to-procedure edits address unbundling; medically unlikely edits cap units for a single date. Commercial payers often adopt them with their own variations.

ModifierClaim scrubbingModifier 59

Reporting a higher-paying level than the documentation supports, or a lower one than it supports.

Upcoding creates compliance exposure and repayment risk. Downcoding is treated as the safe option but is a persistent, unrecoverable revenue leak and distorts the practice's coding profile.

Both are documentation problems. The fix is a coding review against the note, not a policy telling providers to bill lower.

Medical decision making (MDM)Medical necessity9921399214

Medicare policies stating whether and under what conditions a service is covered.

NCDs apply nationally; LCDs are issued by regional contractors and can differ between jurisdictions. Both define the diagnoses, frequency limits, and documentation that support coverage.

Medical necessityPayer mix

Verification of a provider's education, licensure, training, and history before a payer or facility grants participation.

Distinct from enrollment, which is the contracting and payer-file step that actually enables billing. Both must complete before claims will pay under that provider.

A provider who is credentialed but not enrolled, or enrolled with the wrong group affiliation, generates denials that look like billing errors.

Payer enrollmentRevalidation

The process of adding a provider to a payer's participating file so claims can adjudicate under them.

Includes group affiliation, service locations, effective dates, and electronic payment setup. Effective dates control whether services delivered during the application window are billable at all.

Track the effective date, not the approval date. Retroactive windows vary by payer and are frequently the difference between billing and writing off a new provider's first month.

CredentialingRevalidation

Periodic reverification of a provider's credentials and enrollment information by a payer.

Typically required on a fixed cycle. A missed deadline can suspend participation and stop payment on claims that were otherwise clean.

Missed revalidations are among the few RCM failures that are entirely calendar-driven and entirely preventable.

CredentialingPayer enrollment

Confirming a patient's active coverage, plan, and benefit details before the visit.

Covers active status, plan and network, copay and deductible, and any authorization requirement. Because it happens before the service, it is the cheapest point in the cycle to prevent a denial.

Prior authorizationCoordination of benefits

Payer approval required before a service is delivered in order for it to be covered.

Requirements vary by plan, service, and place of service, and can differ for telehealth delivery of the same service. An authorization is not a guarantee of payment, only of coverage review.

Track the authorized code, units, date range, and rendering provider. Claims that exceed any of the four deny even with a valid authorization on file.

Eligibility verificationMedical necessityModifier 95

The rules determining which payer pays first when a patient has more than one plan.

Primary pays to its allowable, then the secondary considers the balance against its own rules. Incorrect order is a high-volume, fully preventable denial category.

Eligibility verificationERA and EFT

The distribution of a practice's revenue across commercial, Medicare, Medicaid, and self-pay.

Drives expected reimbursement, denial patterns, and how much of the balance ends up with the patient. Two practices with identical coding can have very different collections purely on mix.

Net collection ratePatient responsibility

The portion of an allowed amount the patient owes: copay, coinsurance, and deductible.

Determined by plan design and reported on the remittance. As deductibles have risen, this has become a larger share of total collections and a slower one.

Collecting at or before the visit, once benefits are verified, is materially cheaper than statements and follow-up calls.

Eligibility verificationPatient statement cycleBad debt

The sequence and timing of billing communications sent to a patient for a balance.

Typically a series of statements with escalating messaging over a defined period, then a decision point for payment plan, collection referral, or write-off.

Patient responsibilityBad debt

A patient balance the practice has determined it cannot reasonably collect.

Distinct from charity care, which is a documented inability to pay determined by policy. The distinction matters for reporting and for how accounts are treated afterwards.

Write-offPatient responsibility