Research methodology · Lesson 2 of 3

The two big families, and what each answers

Quantitative tells you how much and whether. Qualitative tells you how and why, in people's own terms.

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Quantitative approaches measure. They work with variables recorded as numbers across enough cases to look for patterns, and they answer questions about how much, how many, how often, whether two things move together, and whether a difference is larger than noise.

The main members: surveys describe characteristics across a population; experiments assign conditions deliberately and are the strongest tool for causal claims; quasi-experiments use naturally occurring groups when assignment is impossible; correlational studies look for association without intervening; cross-sectional takes one moment in time; longitudinal and cohort studies follow the same cases over time, which is what lets you say what came first; secondary data analysis uses data somebody else collected, which is fast and constrains you to what they thought to record.

Qualitative approaches interpret. They work with text, speech, observation and artefacts in depth across fewer cases, and answer questions about how something is experienced, what it means to people, how a process unfolds, and why people do what they do in their own terms.

The main members: interviews for individual accounts; focus groups for how views form in company; observation and participant observation for what people do rather than what they report; ethnography for immersion in a setting; case study for a bounded instance in its context; phenomenology for the texture of a lived experience; grounded theory for building theory from data rather than testing an existing one; content, thematic and discourse analysis for systematically working through material.

The honest summary is that quantitative approaches are strong on extent and comparison and weak on meaning, while qualitative approaches are strong on meaning and mechanism and weak on extent. Neither weakness is a flaw; they are what you accept in exchange for the strength.

See it happen

You want to understand employee turnover at a company where it has risen sharply.

The read that arrives on its own

Send a survey — it reaches everyone and gives you numbers you can show the board.

The same situation, with this idea

You ask what you actually need. If the question is how many are leaving, from where, and when, a survey and the HR records answer it well. If the question is why — what the experience was that led to the decision — a survey returns whatever options you wrote, which means you can only learn what you already suspected. Exit interviews or conversations with recent leavers reach reasons you had not thought to list. Most likely both are needed, in that order.

After this, you can

notice when your chosen approach can only return what you already thought of.

The takeaway

Quantitative tells you how much and whether. Qualitative tells you how and why, in people's own terms.

Easy to take the wrong way

That qualitative work is unsystematic. Rigorous qualitative research has explicit sampling, documented coding, and checks on interpretation — the rigour looks different, not absent.

Try this

Write your question twice: once as something countable, once as something to be understood in depth. Which version is the one you actually care about?