Exploratory sequential design

By Dr. Rafiq Muhammad, MD, PhD · Updated June 2026

The exploratory sequential design is the “explore first, then measure” design. You start qualitatively to understand a phenomenon, build a quantitative tool from what you learn — usually a survey or an intervention — and then test or generalize it quantitatively. The qualitative strand leads (qual → QUAN), and the step that makes or breaks it is the build phase in the middle.

The three phases

1. Phase 1 — qualitative. Explore the phenomenon, population, or construct — interviews, focus groups, observation — and analyse it (e.g. thematic analysis) to surface the dimensions that matter.
2. Build. Convert those findings into a quantitative artifact: survey items drawn from your themes, a taxonomy, or an intervention designed around what participants described. Expert-review and pilot it.
3. Phase 2 — quantitative. Administer the new instrument (or trial the intervention) with a larger, often different sample to test, validate, or generalize what the qualitative phase found.

The make-or-break step: the build phase

Everything downstream rests on the quality of the build. If your survey items don’t faithfully represent the qualitative themes, the quantitative phase measures the wrong thing — confidently. Treat instrument development as a real methodological step: map each item back to a theme, get expert feedback on content validity, pilot it, and check the structure (e.g. a factor analysis) before the main quantitative phase. State your building criteria — what the Phase 1 themes must establish before Phase 2 can begin.

When to choose it

Choose exploratory sequential when little is known up front, or when no adequate measure exists for your construct or population and you need to create one. If you already have results that need explaining — the numbers came first — you want the reverse order, an explanatory sequential design. If both strands run together, see convergent parallel. Either way, plan the integration up front.