Knowing When to Look at Averages vs. Subgroup Data

One of the most critical skills for school principals and vice principals is knowing how—and when—to examine different types of data. While average data offers a high-level view of school performance, it often hides important equity issues. Disaggregating data by student groups such as English Language Learners (ELLs), students with disabilities, and students from low-income households can reveal gaps that demand attention.

Average data can be a useful starting point. It allows you to:

• Establish Baselines – Average performance can help you understand the general state of achievement, attendance, or behavior in your school.

• Track Overall Trends – Use average data to evaluate whether whole-school initiatives are moving the needle in the right direction.

• Communicate Broad Outcomes – High-level summaries are often helpful when presenting to district leadership, school boards, or external stakeholders.

However, average data should be viewed as a gateway, not the destination. It tells you what is happening, but not for whom or why. This is when you should look at disaggregated data.

Equity-focused leadership requires going beyond the averages. Disaggregated data helps identify where systems may be failing certain groups of students, even when overall performance looks positive. Here is why disaggregation is essential:

• Uncovers Hidden Gaps – A school may have a high graduation rate on average, but a significantly lower rate for ELLs or students with disabilities.

• Informs Targeted Support – Data by subgroup allows you to develop specific interventions and allocate resources more effectively.

• Ensures Compliance – State and federal guidelines often require schools to monitor and report subgroup performance.

• Promotes Equity and Inclusion – Looking at subgroup data demonstrates a commitment to ensuring success for all students, not just the majority.

Key Subgroups to Examine:

• Multilingual Learners (MLs)

• Students with Disabilities

• Students from Low-Income Backgrounds

• Racial and Ethnic Groups

• Gender and Gender Identity Groups

Practical Steps to Use Subgroup Data Effectively

1. Start with a Guiding Question – Ask: Who is benefiting from current strategies, and who is being left behind?

2. Use a Data Dashboard – Visual tools that display subgroup performance side-by-side can make patterns more visible.

3. Drill Down into Patterns – Go beyond the surface. For example, if MLs are underperforming in math, look at grade levels, classroom practices, or access to supports.

4. Engage Staff in Analysis – Collaborative review of subgroup data helps build shared responsibility for equity.

5. Follow Up with Action – Data without follow-through is just information. Use your findings to drive decisions around instruction, staffing, and resource allocation.

Knowing When to Use Each

Great school leaders don’t stop at averages—they dig deeper to understand the experiences of every student group. By disaggregating data and analyzing subgroup performance, you can uncover equity gaps and respond with targeted strategies that truly make a difference.

Page 15 of this document from Clark County School District includes information on how to look at subgroup data and multiple measures, plus much more!