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Version 1.2 – Updated June 2023

About MetaX


When Professor John Hattie first began his research around performance indicators and evaluation in education, he had one simple question: which variables have the greatest impact on student achievement?

The Visible Learning® research base is the culmination of his quest over the past 25 years to answer this question and represents more than 2,103 meta-analyses comprising more than 132,000 studies involving more than 300 million students around the world.

Through the Visible Learning research, John Hattie has identified more than 320 factors that influence student achievement. He then set about calculating a score or "effect size" for each, according to its bearing on student achievement. The average effect size of these 320 factors was 0.4, a marker that can be shown to represents an (average) year's growth per year of schooling for a student. Any factor that has an effect size above 0.4 has an even greater positive effect on student learning.

Each of these factors have been categorized into one of nine domains

  • StudentFactors relating to background, beliefs, and physical influences
  • HomeFactors relating to family resources, structure, and environment
  • SchoolFactors related to school-type, pre-school, school composition, and leadership
  • ClassroomFactors related to class composition, giftedness, and classroom influences
  • TeacherFactors relating to teacher attributes, teacher-student interactions, and teacher education
  • CurriculaFactors related to various curricula programs
  • Student Learning StrategiesFactors relating to self-regulation, student perspectives, and learning strategies
  • Teaching StrategiesFactors relating to learning intentions, success criteria, feedback, and teaching strategies
  • Technology, School, and Out-Of-School StrategiesFactors relating to technology, school-wide methods, and out of school learning

The Visible Learning research is recognized as the world's largest evidence base on what works best in schools to improve teaching and learning and the Visible Learning MetaX platform, powered by the Visible Learning research, is now the largest global online database of what works best in education.

The power of the Visible Learning research in action lies in helping educators understand, measure, and evaluate the impact that they can have on student growth and achievement. Educators who understand which practices and strategies have the greatest impact on student achievement can make informed decisions based on evidence to maximize their time, energy, and resources.

Our vision for the Visible Learning MetaX database is to proliferate the reach of the Visible Learning research around the world and to exponentially accelerate the use of the research to positively impact student learning.

Who is MetaX for?

Untangling education research can often feel overwhelming, which may be why so many research-based practices can take quite a while to show up in schools and classrooms. Visible Learning MetaX aims to help close the gap between research and practice by identifying the major factors and practices that influence student achievement and accelerate student learning, based in the evidence of what works best.

The Visible Learning research provides insight into what policy makers, teachers, and district/school leaders should stop doing and what they should strive to do better. While nothing works everywhere, Visible Learning MetaX provides educators with research-based 'good bets' that they can adapt to their local context and – when deeply implemented through professional learning services – can lead to stunning results.

Visible Learning MetaX can be used by:

  • District/school leadersSuperintendents, central office staff, principals, and head teachers who wish to a) maintain their professional knowledge about effective interventions at the student, curricula, home, school, classroom, teacher, and school level, and b) identify effective influences that are based in research and support their specific school's agenda and improvement initiatives.
  • TeachersK-12 teachers in public and private schools who would wish to maintain their professional knowledge about effective interventions at the student, curricula, teacher, classroom, and school levels.
  • Education ResearchersUniversity academics who wish to review the meta-analyses on what works best in education to accelerate student learning and cite these in their own research.
  • Policy MakersOfficials from national, regional or district education authorities who wish to review the evidence on what works in education reform to support their own local policy agendas.
  • Doctoral StudentsWho wish to review the meta-analyses on what works best in education and cite these in their own course of study and writing.
  • Educational ConsultantsWho wish to stay current with the ever-evolving Visible Learning research base so that they can better serve their clients.
  • Parents/Community MembersWho are in search of information on what they can do to support and develop their children in the both the home setting and at school, or for home-based educational enrichment activities.

MetaX Functionality

The Visible Learning MetaX global research database is a dynamic platform that offers users unprecedented access to the most up-to-date Visible Learning research, interpretations, and analyses. Core features of the site include:

  • The Influence GlossaryAn alphabetical list of definitions for each of the Visible Learning influences that can be downloaded, printed, and shared.
  • The Global Researcher Database A searchable index containing each of the individual factors that influence student achievement as identified by John Hattie through the Visible Learning research. The database includes the following information for each of the Visible Learning influences and can be filtered based on search preferences.
    • Domain The major domains related to student achievement
    • Sub-Domain Specific sub-domain within the primary domain category
    • Impact on Student Achievement Likelihood of the influence to positively or negatively impact student achievement
    • Number of Meta-Analyses
    • Number of Individual Studies
    • Number of Students Studied
    • Number of Effects
    • Weighted Mean Effect Size Effect size calculated using Cohen's d
    • Robustness Index The standard error, along with the number of meta-analyses, studies, people, and effects have been used to generate a robustness index for each influence. Robustness, in the case of MetaX signals the relative confidence or strength in the stability of the average effect size associated each influence. A robustness index of 5 suggests that the effect size is both stable and high confidence is placed in the research available for calculating an average effect size for MetaX. That is, a robustness index of closer to 5 means that the average effect size is less likely to change with the addition of new meta-analyses. For a robustness index of 1, the average effect size is likely to change with the addition of new meta-analyses.
  • Influence Detail PageA detailed page for a particular influence that features high-level summary data about the influence and offers a more descriptive view of the meta-analyses and discrete confidence factors that underlie the makeup of the effect size and overall confidence score. The Influence Detail page provides citation information and an individual effect size for each meta-analysis used to calculate the overall effect size of the influence and offers confidence factors related to number of meta-analyses, number of studies, number of students, and number of effects behind the research.
  • Frequently Asked Questions (FAQs)A repository of hundreds of questions that have been posed about the Visible Learning research from teachers, leaders, researchers, and policymakers from around the world. Many of these questions have been answered by John Hattie directly and any future questions and comments relating to the Visible Learning research will be posted to the FAQs regularly so that everyone can engage in and learn from our Visible Learning community of practice.

We Welcome Your Feedback

Every correction, critique, and general comment regarding the Visible Learning research and Visible Learning MetaX is welcomed. Please submit your queries here.

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