Third Next Available Appointment: How to Calculate It and Read the Benchmarks

What You Need to Know

• Third next available appointment tells you how long a patient would wait for a real opening on a provider's schedule, counted to the third open slot so one cancellation doesn't skew it¹,².
• After switching to advanced access, practices in 14 primary care studies narrowed their waits from a range of about 2 to 36 days to a range of 1 to 11 days². No national standard sets a target¹.
• Count calendar days at the same time each week, by provider and visit type, and read the result next to your scheduling call volume.

What is third next available appointment, and why count the third slot instead of the first?

Third next available appointment (TNAA) is the average number of days a patient would wait, from the day they ask, for the third open appointment on a provider's schedule¹.

One cancellation can open a slot tomorrow and make a long wait look like a short one². Counting the third slot smooths that out. That's a key reason it's widely recognized as the standard access measure in primary care². It does take more care to count the same way every week³.

How do you calculate third next available appointment?

Pick a fixed time each week, count calendar days to each provider's third open slot, then average across providers.

1. Measure at the same time every week, such as Monday before clinics open³.
2. For each provider and visit type, find the third open slot. Skip slots held for specific groups or procedures, such as obstetrics, pediatrics or minor surgery².
3. Count calendar days from measurement day, which is day 0. Weekends and the provider's days off count too³.
4. Average across providers, both simply and weighted by each provider's weekly visits.

Here's a made-up example: three providers' next open new-patient slots as of Monday, October 5, before clinics open.

ProviderNext 3 open slotsFirst availableThird availableWeekly new-patient visitsAOct 8 (cancellation), Oct 20, Oct 263 days21 days30BOct 6, Oct 6, Oct 71 day2 days10CNov 2, Nov 4, Nov 928 days35 days20

Across the three providers, third next available appointment averages about 19 days. First available averages about 11, but Provider A's October 8 opening is a cancellation. Without it, A's first available would be 15 days instead of 3. The third slot still counts that opening, but it moves less when cancellations open early slots².

Weighting by weekly visits raises the average to 22.5 days, because the two busiest providers, A and C, have the longest waits.

Write down whether you count calendar or business days. Provider A's third slot is 21 calendar days out, or 15 business days if the October 12 holiday counts as a workday.

How often should you measure third next available appointment, and how should you split it across providers and locations?

Measure weekly at the same day and time, and report each provider, visit type and location separately before rolling them up.

A clinic average can hide one provider's backlog, so look at providers one by one first. Keep new and return visits apart, break out each location and specialty, and make sure every site counts the same way.

Once a practice can see patients the day they call, the Agency for Healthcare Research and Quality (AHRQ) suggests checking daily⁴. Keep logging the weekly number too, so you can compare over time. For the board, one monthly figure is enough: the weighted average of that month's weekly readings.

If your group schedules centrally, one shared sheet can hold every site.

ColumnRecordHeaderCounting basis and measurement timeLocationOne tab per locationProvider and visit typeOne row eachWeek columnsDays to the third open slotWeightWeekly visits of that typeRoll-upSimple and weighted averages

What can third next available appointment tell you, and what does it miss?

Third next available appointment tells you how far out your open slots sit. It can't see patients who never got through to book, and it shifts with how you count.

Before you compare two sites, check that they count the same way: calendar or business days, the same slots left out, and the same time each week.

Waits to the third slot and patient ratings don't always move together. At one Toronto primary care practice, longer waits lined up with only one of five patient-reported access measures⁵. Patients rated timely access to their last booked appointment worse⁵. The other four, including same-day phone responses and after-hours care, showed no clear link⁵.

The study was small⁵, and its authors concluded access "is best assessed using multiple measures"⁵. The Institute of Medicine (IOM) has also noted that scheduling assessment tools capture patients' views of acceptable waits poorly¹.

What is a good third next available appointment?

There's no national standard for a good third next available appointment¹. What exists are results from primary care practices that switched to advanced access, where the rule is to "do today's work today"⁴.

Before switching, practices in 14 studies had waits to the third slot ranging from about 2 days to 36 days². After the switch, the range dropped to 1 to 11 days². Waits fell in all 14 studies, nine significantly, and six got to 2 days or fewer².

The review rated most of these studies at serious risk of bias, and they date from 2001 to 2018².

BenchmarkFigureSourceNational standardNone (as of 2015)Institute of Medicine¹Range across 14 primary care studies, before advanced accessAbout 2 to 36 days2026 review²Range across the same studies, after1 to 11 days2026 review²Routine wait, one Kaiser Permanente clinic55 days to 1 day in under a yearAHRQ, single site⁴Medicaid managed care maximum wait from request (a different measure), where covered≤15 business days: primary care, OB/GYN. ≤10: outpatient mental health and substance use. Plus another covered service the state picks42 CFR 438.68(e), plan rating periods from July 9, 2027⁶

The Medicaid limits in the last row measure something different: the routine wait from the day of request. When a state's managed care contracts cover primary care, the rules require the state to set its own primary care limit⁶. That limit can be shorter but must be "no longer than 15 business days from the date of request"⁶.

These limits apply to health plans starting with rating periods on or after July 9, 2027⁶. You can keep tracking third next available appointment in calendar days alongside them.

None of these studies gives a figure for specialty clinics. There, track your own trend by visit type. It shows whether access is getting better, though not whether it's good enough.

How does third next available appointment connect to demand, capacity and the phones?

Third next available appointment shows how much room your schedule has, and your scheduling calls show how many patients want in. Read them side by side each week, using healthcare call center metrics such as abandonment and speed of answer for the phone side.

• Long waits to the third slot: demand exceeds your open capacity, so answering more calls books patients further out. Clear the backlog first. AHRQ says a group "may need to see more patients each day for 6 to 8 weeks," and every practice in one study it cites found that hard, especially larger ones⁴.
• Short waits, but unanswered calls: you have open slots that callers can't reach, so each answered call can become a visit.
• Short-notice openings: cancellations open early slots, which fill only when someone offers them, for example to the next caller or in an automated message from patient engagement software.

Before you push to increase patient volume, check that your appointment types leave room on the schedule. Then estimate how much of that demand your open schedule can absorb. The calculator only counts visits your schedule can take, so a full schedule shows nothing to recover.

How do Commure AI Call Center Agents handle the scheduling demand that third next available appointment misses?

Commure AI Call Center Agents answer the scheduling calls that third next available appointment can't see, at any hour and in English or Spanish. They book callers into the schedule you already have by the rules you set and pass unusual requests to your staff, adding call center capacity to answer and book more calls.

Their dashboard shows every call and whether it succeeded, which gives you a weekly demand count to read beside your third next available appointment numbers. If you don't count scheduling calls by outcome yet, ask for a complimentary call center health analysis.