Mastering User Research: The Z Method for Effective Product Planning

A while ago I came up with the “Y Theory”, and recently I organized a “Z Method”, which I find practical for implementation, and invite everyone to take a look.

There are many methods for requirement gathering, or user research, and a classic classification is the two‑dimensional matrix of qualitative vs quantitative and say vs do . Let’s briefly review the previous discussion:

Horizontally, qualitative versus quantitative.

Qualitative research can uncover reasons and leans toward understanding, while quantitative research can reveal phenomena and leans toward verification. Both are essential; relying only on quantitative data may “replace substance with numbers”, seeing problems without knowing causes, whereas relying only on qualitative data may “generalize from a biased sample”, leading astray. People usually move from qualitative to quantitative and back again in a spiral, iteratively deepening both understanding and validation.

Vertically, what users say versus what they do.

What users say reflects goals and opinions; what they do reflects behavior, and the two are often inconsistent. Both aspects matter. I once believed “what you hear is false, what you see is real”, so observing actions seemed more reliable than listening to words, but later realized that actions alone do not reveal underlying reasons, and without knowing causes you cannot solve problems fundamentally. Therefore we must both watch what users do and listen to what they say, even though spoken statements may not always be truthful.

The most common methods in the four‑quadrant framework are user interviews, surveys, usability testing, and data analysis . This content has been mentioned before, but I recently arranged these methods into a “Z” shape to help colleagues remember them—a simple, combined approach for requirement gathering.

The “Z Method” for requirement gathering

Combining say/do and qualitative/quantitative dimensions in a reasonable mix yields the greatest impact. Different product phases can use different methods. Below is a typical example that employs the four methods, drawn as a capital “Z” from top to bottom, left to right.

First round – product planning stage: Listen to users qualitatively to determine product direction. Conduct random interviews with 40 users and compile a requirements list.

Second round – early project stage: Listen to users quantitatively to prioritize requirements. Distribute 200,000 survey questionnaires to rank priorities.

Third round – implementation stage: Observe users qualitatively in action to decide how to address the top requirements. While designing, involve 10 users for validation through usability testing.

Fourth round – post‑launch optimization: Observe users quantitatively by analyzing product usage data, continuously improving the product.

For detailed steps, refer to other materials. This is a relatively important product, so considerable time and manpower were invested in user research; often we adopt simplified schemes based on circumstances.