5 Substitute Staffing Tips from Gwinnett County Public Schools for Stronger Fill Rates

Every unfilled absence is a decision that affects someone else. It becomes a class split between two rooms, a planning period surrendered, a paraprofessional pulled off a student who needs her. Most districts treat that as a given rather than something they can impact. To address it, the obvious lever is pay, but when we compared state-level substitute wages against absence data, higher pay didn’t track with better coverage.

The metric with the clearest effect on fill rate was the share of a district’s existing substitutes who actually pick up work. Gwinnett County Public Schools tested that finding: they made it more difficult to become a substitute teacher, and their fill rates went up. 

Why does the substitute problem feel unfixable? 

Absence is permanent, and no district engineers it away. Polled during a recent session on substitute strategy, administrators named filling last-minute absences as their top challenge, then finding enough qualified substitutes at all. 

The field’s first instinct is volume. Lower the bar and widen the funnel to grow the pool and cover more absences. It’s where Gwinnett started. But chasing volume can damage the coverage you already have. Kevin Agnello, Group Product Manager at Frontline Education, is blunt about the belief he hears most:

“There’s a common belief that teachers and staff, they’re going to be absent, of course, but whether a substitute accepts that job is largely random, and there’s not much an administrator can do about those things…Districts live with the consequences of unfilled absences every day, but many don’t approach the problem with data.”

Where this advice comes from 

In September 2026, Frontline and Education Week hosted a conversation on data-driven substitute strategy between Agnello and Velia Verdiguel, Interim Director of Human Resources at Gwinnett County Public Schools in Georgia. Verdiguel has been with Gwinnett nineteen years, thirteen in HR, and spent the period below as senior HR manager over substitutes. The district runs 143 schools, employs roughly 13,000 teachers, staffs its substitute department with a team of seven, and uses no emergency staffing agency. Here’s what we learned.

Tip #1: Break your fill rate apart before you change anything

Fill rate — the proportion of absences requiring a substitute that are actually filled by one — is the number most districts watch, usually as a single district-wide figure. That figure is where Gwinnet’s first strategy hid something vital. Coming out of COVID, the district dropped its substitute teacher requirement to a high school diploma. The teacher fill rate rose, but so did something else. 

Segment fill rate by role, not just by district

“Because we have maybe four or five different categories of employees that are eligible for substitutes, it really helped beef up that substitute teacher fill rate, but it then lowered the fill rates for our substitute paraprofessionals, our clinical staff, our clerical roles, our custodians, because why would I go and pick up a job that pays less when I can go in and pick up an assignment that pays $130? So there’s nothing to differentiate in that category.”

The lowered standard opened teaching assignments to everyone, and everyone went where the pay was. Special education classrooms lost paraprofessionals and clinics lost coverage, but those things weren’t visible in the district-wide average. Gwinnett now pulls fill rates monthly, by school and title status — segmentation that does more than diagnose. It funds things.

“We then use that fill rate data to support the need for a permanent substitute in the building, and we call them ‘stellar subs’ here. A lot of our elementary and middle schools were then able to go from one stellar sub in the building to two stellar subs to help with some of those unfilled classroom needs. And so that was one of the things that we got to do as a result of the data.”

Stellar subs are full-time benefit-eligible staff assigned to one building. 

Don’t let one average stand in for a strategy

A district-wide number can’t tell you whether a policy improved coverage or just moved it from lower-paying roles to higher-paying ones. Pull it by role and building before you touch a requirement, pay rate, or incentive — the relationship between substitute pay and fill rate is less direct than it looks.

Tip #2: Hire for quality even when it shrinks the pool

Three to four years on, Gwinnett reinstated its pre-pandemic requirement: sixty semester hours, ninety quarter hours, or an associate’s equivalent to substitute as a teacher. Applicants who didn’t meet it were still welcoming in paraprofessional, clerical, clinic, and custodial roles, and existing substitutes were grandfathered. 

Move through quantity, then qualified, then quality 

These are three different things. Gwinnett looked at each them in order.

“We were looking at first quantity, then we’re looking at qualified, meaning that you have the educational experience to back it up. And then quality, more so, this is a good person that should be in front of our students on a day-to-day basis.”

The quality stage changed hiring itself: phone screenings built on the district’s core competencies for classified staff, plus reference checks. Verdiguel frames the payoff as a staffing one.

“That was a goal just to get more qualified and quality substitutes in, which as a result of doing that is to also increase the number of substitutes that are converting over into permanent roles as paras or teachers…Because we all know there are not enough teachers out there, but I think we can all recognize that a lot of our substitutes and even our other classified folks can build into those roles if you really design it correctly.”

Don’t mistake a lowered bar for a strategy 

Here’s how Verdiguel described the volume era: “It was almost like a free for all. ‘If you have a pulse, come join the team.’” 

Two costs followed. Buildings reported performance concerns, some involving substitutes just out of high school, and turnover climbed, because the job had been undersold: “I don’t think we did a good job communicating what the job really entailed.” 

Resistance to reversing course went straight at the metric. Verdiguel recalled the reasoning: “If we make the change, will we still continue to have great fill rates? Because that would be unknown.” The teacher rate kept climbing anyway while classified rates recovered, and the people closest to daily coverage were the most relieved:

“Our local school administrative assistants specifically were ecstatic to say now they knew that it would bring additional subs in the building to fill into those additional roles that are definitely needed throughout the day.” 

Gwinnett finished 2025-26 just under a 95% overall fill rate for substitute teachers, with about 4,400 active substitute teachers and no school below 70%. When Verdiguel took over, some schools were in the forties.

Tip #3: Tell substitutes what the job actually entails, before day one

The turnover problem wasn’t only a screening problem. It was an expectations problem. 

Use onboarding to remove surprises, not to re-teach

Georgia requires four hours of substitute training for candidates without a teaching license. Gwinnett built the course in house rather than buying it, so applicants don’t pay. Candidates finish it before onboarding, which frees that session for the terms of the job:

“We really focus on the business components of being a substitute, compliance, as well as the pay structure…It’s not a surprise when I get to the school and the school expects me to walk around and engage with students because I’ve already been told when I was hired what it is that is expected of me. So we go ahead and set the stage for them.”

Don’t assume the posting explained the job 

“Walking into the classroom as a substitute was hard for someone to take on,” Verdiguel said, “because they didn’t really understand that a substitute did not just sit behind a desk. You actually have to get up and engage.”

A substitute who learns that at 8:05am on a first assignment is one you’re likely to lose. Preparing substitutes for what the classroom will ask of them is cheaper than replacing them.

Tip #4: Treat building culture as a fill rate variable

Gwinnett lets substitutes choose their own assignments. Teachers enter an absence, substitutes pick it up. That turns the monthly fill rate report into something closer to a preference survey. 

Investigate why subs skip one building and not the one down the road

“When we see that a school is maybe struggling to get substitutes in the building, we take a deeper dive at that school and say, ‘What are some of the things that could be happening where a substitute is willing to go to school A, but they’re not so wiling to go to school B and school B is maybe five minutes down the road?’” 

Verdiguel opens that conversation with principals without putting them on the defensive: 

“When I’m talking to schools, I always say, ‘Tell me what your favorite grocery store is.’ And they’ll tell me what their favorite store is and why. ‘Now tell me what your least favorite store is and why.’ And so that’s always some good conversation…People want to go where they feel good, where they’re having a great experience.” 

The district turned that into standing training for buildings — The Great Substitute Experience — and surveys substitutes on whether they feel part of the team. 

Don’t treat an empty classroom as bad luck 

The interventions that close a building-level gap don’t have to be massive efforts:

“It doesn’t cost you anything to put on a smile, to welcoming someone into your building. You know, the little things count. The little trinkets, what we call the school swag. You may have some extra pencils, or maybe you can afford some coffee for the substitutes. Coffee goes a long way for a lot of folks.”

Gwinnett does also pay a semester incentive: $500, $750, or $1,000 for substitutes working 45-59, 60-74, and 75 or more days. About 800 earn it each semester. Roughly 95% of Gwinnett’s pool works at least one assignment a year — the working substitute percentage that Frontline’s analysis flagged as the strongest driver of fill rate.

Tip #5: Staff next year’s worst day using last year’s data

The highest-absence day on Gwinnett’s calendar is the same one every year: the Friday going into Mother’s Day weekend. Verdiguel has seen about 1,800 teachers out on that one day. 

Warn buildings a week ahead of a predictable spike

“We already know that on this specific day, we tend to have a high number of absences. So if we can get ahead of it, we go ahead and start reaching out to our schools about a week in advance to say, ‘Hey, just want to let you know we are anticipating a high number of absences next Friday. Please go ahead and start getting prepared to get those filled.’ And that has worked very well for us, and our principals have thanked us on more than one occasion.”

The team works the supply side months out too, asking incoming substitutes during onboarding to hold the date. Agnello argues the ceiling on this kind of planning is high:

“Absence totals, particularly employee teacher absences, are surprisingly predictable year of year using your own district’s data. If you were to match up the Tuesday after Labor Day to the Tuesday after Labor Day, for examples, and through it into a pretty basic model, you can get to about 90% or above accuracy in predicting the next entire school year of absences.”

Don’t save your attention for the morning-of scramble

Asked to characterize their district’s substitute strategy, the largest groups of administrators in the session chose “reactive” or “not yet strategic.” That’s what happens when the only time anyone opens the absence data is while trying to cover today. Pull last year’s calendar, find your five worst days, and tell your principals in advance. 

In summary

Gwinnett’s results didn’t come from a bigger substitute pool. They came from reading the fill rate closely enough to see which roles a well-intentioned policy was pulling substitutes away from, then changing the policy. Everything after that was already inside the district’s control: what the hiring bar is, how the job is described, what a building feels like to walk into, and which days to warn people about. Pull your fill rate by role and by school this month, and start with the biggest gap.

“Your fill rates are going to tell you the most. You can look at it from a large scale looking at all of your data. You can also drill down into your schools that are high performers when it comes to fill rates. And then you can look at some that maybe need a little bit of support. Fill rates all day long is the first thing that I would look at. It tells the story.”

Frontline Absence Management is where staff enter absences and substitutes pick up jobs. Human Capital Analytics is where that data becomes a fill rate you can read by school and by role.