The value of interview experience lies not in how many people you ask, but in recognising what does not fit

In the previous article, I described a recent investment research project involving a highly specialised industrial niche.

During the initial interviews, experts from different companies and professional backgrounds almost unanimously endorsed the same optimistic market-size forecast.

What made me question the forecast was not a dissenting view from inside the sector.

The opposite was true: the expert opinions were remarkably consistent.

The concern came from previous work on a different upstream industry.

Based on what I had learned about the size and downstream application mix of a core raw-material market, the forecast endorsed by the experts would have transformed a previously limited sub-application into one of that material’s most important end markets.

The two assumptions could not easily be true at the same time.

We therefore changed the direction of the research. Instead of adding more similar interviews within the same niche, we traced the original source of the forecast and looked elsewhere in the value chain for evidence that could support or challenge it.

This raises a reasonable question.

When several industry experts accepted the same data, why did I think of raw-material figures from a different sector?

It was not because I understood their industry better than they did.

Nor was it an unexplained piece of intuition.

A more accurate explanation is that the question emerged from more than 25 years of China-related research: sustained interview practice, industry knowledge retained across projects, and a habit of comparing what people say with other available facts.

The most valuable part of an interview often begins when the interview guide stops being enough

Most research projects begin with an interview guide.

The guide helps ensure that important issues are covered and provides a degree of consistency across different interviews.

But a valuable interview is rarely just a matter of asking every question in the guide in order.

An expert’s answer may reveal a customer relationship that was not previously known, an overlooked cost factor or a timeline that does not match the public record.

At that point, the researcher needs to make several decisions in real time.

Does this statement change our existing understanding?

Is the expert describing direct experience, offering a professional inference or repeating something heard from others?

Is the causal chain in the answer complete?

If the statement is correct, what other facts should also be observable?

Should the researcher return to the interview guide, or pause and follow this point further?

Interviewing ability is therefore not simply conversational skill. Nor is it only the ability to make an interviewee speak more openly.

It is the ability to understand what the person is saying and identify which part of the answer requires an immediate follow-up.

A follow-up question is not a display of verbal agility. It begins with recognising the distance between an answer and the facts already available, and asking the next question that may narrow that distance.

This is difficult to acquire from a standardised questionnaire alone.

It requires repeated practice: listening to answers, distinguishing different types of information, noticing incomplete causal explanations and changing the next question in response to what has just been learned.

For more than 25 years, interviews have been one of my principal research methods.

I spent approximately the first seven years of my career in investigative reporting. Since then, I have worked extensively on commercial investigations, background due diligence and investment-related research for institutional investors and corporate clients in China and internationally.

Across these projects, I have interviewed management teams, current and former employees, customers, suppliers, distributors, competitors and other industry participants.

Their accounts were compared with corporate records, judicial and regulatory information, public announcements, tender records, industry data, media coverage and other public sources.

The industries and assignments changed, but the central discipline remained consistent.

One source can provide a lead. It cannot automatically become a conclusion.

One answer can open a new direction. It can also be a repetition of a market narrative that has not yet been tested.

The researcher’s task is to understand information during the conversation and continue verifying it after the conversation has ended.

Following an expert’s answer does not require knowing more than the expert

In an expert interview, the researcher cannot know more than the interviewee about every technical detail.

Nor should the researcher pretend to do so.

What is required is enough knowledge to understand the commercial logic being described and identify the assumptions on which that logic depends.

Suppose an expert predicts rapid growth for a particular product.

The researcher may not understand the product’s technology as deeply as the expert, but can still ask:

Which customers will generate the growth?

Why are those customers adopting the product?

Has the demand already materialised, or does it remain at the planning stage?

How much capacity, raw material and capital investment would the forecast require?

If the market is genuinely growing at that rate, what corresponding changes should appear in supply chains, pricing, procurement and the competitive landscape?

These questions are not intended to challenge the expert’s professional standing.

They are intended to establish what facts support the expert’s judgement and how far that judgement can reasonably be extended.

Being able to follow an expert does not simply mean keeping the conversation moving in the direction chosen by the interviewee.

It means being able to place a new concept, number or causal claim within an existing view of the value chain, and assess quickly what it supports and what it contradicts.

Sometimes that assessment can be made during the interview and converted directly into a follow-up question.

At other times, the researcher can only record the concern, conduct desk research afterwards, and then test it through new documents or additional interviews.

Interviewing and desk research are therefore not separate activities.

They form a cycle:

Form an initial hypothesis
→ Conduct interviews
→ Identify new facts or contradictions
→ Carry out desk research
→ Revise the hypothesis
→ Select new sources
→ Test again

Interviews provide information.

Desk research helps determine how different pieces of information relate to one another.

Additional interviews are then used to test the revised hypothesis.

Industry knowledge should not disappear when a project ends

Commercial investigations can cover a wide range of industries.

Over the course of my work, I have been involved in projects across manufacturing, information technology, consumer markets, healthcare and other sectors.

This does not make me an expert in every industry.

But every investigation leaves behind knowledge that may remain useful in a later project:

the basic structure of a value chain;

the applications and flows of important raw materials;

how customers make purchasing decisions;

the difference between channel inventory and end demand;

the relationships that should exist among capacity, orders, revenue and cash flow;

and who produces a particular type of market data before it enters the public information environment.

Individually, these observations may appear relevant only to a specific assignment.

Accumulated over time, they become reference points for understanding new questions.

When a new interview conflicts materially with those reference points, experience does not immediately tell me which side is correct.

It provides an earlier and more limited warning:

There may be a contradiction here that has not yet been explained.

That was what happened in the case described in the previous article.

We were investigating niche market A, but the concern came from knowledge retained from earlier work on the raw-material market in upstream sector B.

If all knowledge had been discarded at the end of each project, we might have remained inside market A, continued interviewing similar experts and collected more versions of the same optimistic answer.

Because we retained a basic understanding of market B, we could view the forecast for A from a different position in the value chain and identify, within a limited research period, the contradiction that required further investigation.

The value of cross-industry experience is not that it gives the researcher the answer in advance. It provides more constraints and reference points against which a new claim can be tested.

Experience changes how quickly a problem is recognised and the research direction is adjusted

Experience does not guarantee that a researcher will always be correct.

Working on more projects does not justify skipping verification and reaching conclusions from past impressions alone.

On the contrary, experience should make a researcher more conscious that previous knowledge may be outdated, that two apparently similar industries may differ in a critical way, and that a historical pattern may not apply to a new company.

Experience is not a substitute for evidence.

Its role is to help the researcher ask a more valuable question sooner.

When a market forecast conflicts with upstream data, should the team continue adding experts from the same sector, or move towards raw-material suppliers?

When a company says its customer relationships are stable, should the team ask management again, or identify people who were directly involved in procurement, product adoption and supplier evaluation?

When multiple experts express the same opinion, should it be reported as industry consensus, or should the team investigate whether that agreement originated from the same public material?

These decisions determine where limited research time is spent and what evidence the project will ultimately obtain.

The timetable for investment research is usually constrained.

Clients do not need an unlimited number of interviews and documents.

They need the research team to identify which contradiction could change the investment judgement and concentrate further work on that issue.

This is another capability that develops through long experience.

It is not a matter of possessing more ready-made answers.

It is the ability to decide more quickly where the next piece of evidence should come from.

What remained after 25 years was not a fixed set of answers

Looking back over more than 25 years of work, I cannot reduce interviewing ability to a single technique.

It is not a fixed list of questions or a standard script that can be applied to every industry.

It is closer to a set of working habits developed over time:

When an interviewee speaks with great confidence, confirm why that confidence exists.

When several experts agree, trace where that agreement began.

When an explanation appears logically complete, test whether it is compatible with other observable facts.

When a contradiction emerges, do not rush to declare one side wrong. Convert the contradiction into a question that the next stage of research can test.

Experience does not automatically provide the answer.

What it provides is sensitivity to anomalies, restraint about the limits of evidence, and the ability to decide more quickly when the direction of research needs to change.

The value of interview experience lies not in how many people a researcher has spoken to.

It lies in recognising, even when every answer sounds reasonable, that something may still remain unexplained.