In-Depth Interviews vs Focus Groups: Choosing the Right Research Method
Every week, clients ask: "Should we do focus groups or in-depth interviews?"
The answer is always "it depends." But that's unhelpful. Here's how to actually think through the decision, because choosing wrong doesn't just waste budget. It produces misleading insights that look like valid findings.
According to Enterprise Singapore's market research guidelines, qualitative research remains essential for understanding consumer motivations in Singapore's diverse market. The Singapore Business Federation regularly emphasizes research-driven decision making for SMEs entering new segments.
The Fundamental Difference
Focus groups gather 6-8 people to discuss a topic together. The interaction between participants is part of the data. You're observing how opinions form, shift, and collide in social context.
In-depth interviews (IDIs) are one-on-one conversations, typically 45-90 minutes. The depth comes from sustained individual attention. You're exploring how one person thinks, feels, and decides without social influence.
Neither is inherently better. They answer different questions. Choosing the wrong method is like using a hammer when you need a screwdriver—you might get something done, but not well.
When to Choose Focus Groups
When you want to observe social dynamics
How do people talk about your category with others? How do opinions shift when challenged? Focus groups reveal social construction of meaning that individual interviews miss.
Example: Understanding how parents discuss children's nutrition with each other. The social pressure, the competitive dynamics, the signaling. These only emerge in group settings. HPB's National Nutrition Survey data shows parental influence on children's eating habits—but focus groups reveal how that influence operates socially.
When you need to generate options rapidly
Brainstorming and co-creation work better in groups. Participants build on each other's ideas. What one person suggests sparks different thinking in another.
When budget and timeline are constrained
Focus groups are more efficient. Eight people in two hours versus eight hours of separate interviews. If you need breadth with limited resources, groups make sense.
When the topic benefits from normalization
Some topics feel easier to discuss when others share similar experiences. Taboos and stigmas become more approachable when participants realize they're not alone.
When to Choose In-Depth Interviews
When the topic is sensitive or private
Personal health, financial details, relationship problems, embarrassing behaviors. People won't share these in front of strangers. They might share one-on-one.
Example: Understanding how consumers manage chronic illness. MOH's chronic disease statistics show rising prevalence, but the daily coping details, medication adherence challenges, and emotional impact require individual privacy to surface.
When you need decision journey depth
Complex purchase decisions unfold over time with many factors. IDIs allow you to map the full journey without group discussion fragmenting the narrative.
When participants might influence each other negatively
Some topics, once stated publicly, become stuck positions. If you want honest views before social pressure shapes them, interview individually first.
When your audience is hard to gather
Senior executives, medical specialists, people with unusual conditions. MOM's occupational data shows these professionals are time-constrained. Getting eight of them in the same room is logistically difficult. Individual interviews are more flexible.
Research Framework: Decision Matrix
Focus Groups vs. IDIs by Research Goal
| If Your Research Goal Is... | Focus Groups | IDIs |
|---|---|---|
| Understand social influence on decisions | ✅ Better | ❌ Misses it |
| Explore sensitive personal topics | ❌ Inhibits sharing | ✅ Better |
| Generate new ideas or concepts | ✅ Better | ⚠️ Limited |
| Map individual decision journeys | ⚠️ Gets fragmented | ✅ Better |
| Test reactions to concepts/stimuli | ✅ Better | ⚠️ Okay |
| Reach hard-to-gather audiences | ❌ Logistics difficult | ✅ Better |
| Understand range of individual variation | ⚠️ Suppresses outliers | ✅ Better |
Tool: Category-Method Recommendations
Which Method for Which Research Topic?
| Research Topic | Recommended | Why |
|---|---|---|
| Brand perception | Focus Groups | Social construction of brand meaning |
| Purchase journey mapping | IDIs | Complex individual narratives |
| Concept testing | Focus Groups | Rapid reaction, idea building |
| Sensitive health topics | IDIs | Privacy enables honesty |
| B2B decision making | IDIs | Individual stakeholder perspectives |
| Consumer segmentation | Both | Groups for breadth, IDIs for depth |
| C-suite research | IDIs | Scheduling constraints, ego dynamics |
| Price sensitivity | Focus Groups | Trade-off discussions reveal truth |
When to Use Both Methods
The most robust research often combines methods strategically:
IDIs First → Focus Groups Second
Use individual interviews to map the territory. What themes emerge? What language do people use? Then use focus groups to explore how those themes play out socially.
Focus Groups First → IDIs Second
Use groups to generate hypotheses and identify interesting segments. Then use individual interviews to go deep with specific types of consumers.
Different Methods for Different Segments
Some audiences work better in groups; others need individual attention. Match method to audience rather than forcing audience to method.
Practical Considerations
Factor Focus Groups In-Depth Interviews Cost per participant Lower Higher Scheduling complexity Higher (coordinating 8) Lower (individual slots) Data per participant Less (shared time) More (dedicated time) Moderator skill needed High Moderate Analysis complexity Higher (interactions) Lower (single narratives) Online feasibility Challenging Easy
Common Mistakes
Defaulting to focus groups because they're familiar
Many researchers overuse focus groups. They're comfortable and produce obviously social data. But the question should drive the method, not habit.
Using focus groups for sensitive topics
If participants won't share honestly in a group, you've wasted money. Sensitive research requires safe conditions.
Using IDIs when social dynamics matter
Some insights only emerge through interaction. Individual interviews on inherently social topics miss half the story.
Under-investing in moderator quality for groups
Good focus group moderation is harder than good interview moderation. Groups can go wrong in more ways. The skill premium is worth paying.
The right method produces the right insights. The wrong method produces data that misleads. Start with your research questions, then select the approach that actually answers them.
At Singapore Insights, we help clients choose the right qualitative method—and design studies that answer the actual question. If you're planning qualitative research in Singapore, let us have a conversation. You can also write to our Research Lead, Felicia at felicia@assembled.sg or give us a call at +65 8118 1048.
