Introducing The Science: the research behind our method

October 14, 2026 · 2 min read

Districts ask how a diagnostic works before they trust what it does. The Science is our answer, in plain terms.

What’s on the page

• How SubjectPath measures. SubjectPath estimates each student’s ability with Item Response Theory, using a Rasch-family model with a guessing floor for multiple-choice questions. The page shows the model and explains each part of it.
• Beyond a single number. Each Path maps its standards as a graph of prerequisites, and answer choices are written to reveal specific misconceptions, drawn from a controlled catalog.
• Research behind the method. Published work on formative assessment, mastery learning and knowledge space theory, each with a note on how SubjectPath applies the idea.
• Research by subject. Studies on how students learn math, science, reading and languages.
• References. Every source, including the measurement and adaptive testing work, with a link to the original.

Honest about where we are

The page also says what we don’t know yet. Each question’s difficulty starts as an expert estimate on a common scale, and those estimates have not yet been refined with student response data. Refining them needs pilot data.

The studies on the page are about the approaches SubjectPath uses, not about SubjectPath itself. We think that distinction matters, so we draw it everywhere we cite research.

Why we wrote it

Districts evaluating a diagnostic tend to ask the same questions. How does it decide what to ask next? What does a wrong answer tell it? What research is the method built on, and what does that research actually say? The Science answers those questions in one place, with every source linked so anyone can check it.

Who it’s for

• Curriculum and assessment teams comparing diagnostics and asking how each one measures.
• Intervention and MTSS leads who want to know how the diagnostic reaches a student’s starting point.
• Anyone asked to explain a tool to a school board, a committee or colleagues.

If a question isn’t answered there, get in touch and we’ll walk you through it.