When teachers at Lucas Gardens School, on Wangal land, talk about their students, they can do so in extraordinary detail; what each child can do, how they learn best, and what comes next on their journey.

That depth of knowledge is the result of a deliberate, whole-school commitment to using data as a tool for understanding every student, not just tracking them.

Principal Jenny Zagas said it was not just collecting data for the sake of data.

"What matters is student learning and growth. Data helped us to really know our students," she said.

"You could talk to any teacher in the school, and they would be able to tell you, in detail, what their students can do and how they learn."

Lucas Gardens School, a K–12 school for specific purposes in inner-west Sydney, serves 78 students with moderate and severe intellectual disabilities, many of whom have more than one identified disability and come from a language background other than English.

In this school, the ability to understand each student clearly and communicate that understanding across the whole school is essential.

Teachers use a range of tools, from classroom observations and work samples to student feedback and photographs and use structured protocols that turn those observations into measurable, comparable information.

Goals are broken into smaller steps, progress is monitored regularly, and when a student's learning trajectory starts to plateau, teachers investigate why.

“Sometimes the data reveals something unexpected,” Ms Zagas said. “A student struggling with literacy or numeracy might be dealing with sensory processing challenges or difficulties with self-regulation. Data makes those hidden obstacles visible.”

The evidence also shows that effective data use must examine information about all students, not just those at risk, and challenge assumptions rather than confirm them.

At Lucas Gardens School, that means data informs not just literacy and numeracy goals, but communication, regulation, mobility and wellbeing.

Students' diverse abilities, accomplishments and goals are visible and understood by every staff member.

Data also enables close collaboration with families, providing specific measures and outcomes to share and discuss, creating more time to listen and to understand students through the perspectives of the people who know them best.

School-wide assessment tools and a shared language that runs from Kindergarten to Year 12 create a sense of consistency throughout Lucas Gardens School

The school's approach is profiled in the NSW Department of Education's latest What Works Best resources which contains specific resources on best practice use of data to inform teaching.

The What Works Best evidence guide shows purposeful data use as foundational to good teaching, as it can underpin high expectations, explicit instruction, effective feedback, and ongoing assessment – all of which leads to improved student outcomes, no matter the school’s size or context.

It also points to research showing that teacher collaboration around data can reduce professional isolation, sharpen individual judgement, and help schools better identify student needs.

Collaboration works best when structures are in place and everyone has the skills to participate meaningfully, meaning ongoing data literacy professional learning is crucial.

At Lucas Gardens School, building those skills is a year-round commitment. Every new teacher is assigned a mentor, and once per term, all staff attend a one-hour, data-specific professional learning session during school hours.

Each week, the assistant principal for curriculum and instruction works shoulder-to-shoulder with teachers in their classrooms, observing, coaching and discussing data analysis, while twice each term, staff hold data collaboration sessions where teachers upload data to a central system and talk through student progress together.

Assistant Principal Jen Angelini said the collaborative analysis was a great opportunity for staff.

“If they've got a difficulty with something, we can discuss solutions," she said.

"It's also an excellent opportunity for new teachers to be supported by more experienced teachers."

As the evidence guide shows, the purposeful use of data, combined with professional development and collaboration is appropriate for all schools, no matter their size or context.