In short
A research question is testable when it states what changes, what will be measured, under what conditions, and in whom, so that a result could prove you wrong. Getting from "I wonder if …" to that point is often the hardest part of a study. In this track, you'll design, run and report a small study that someone else could check. This first lesson will decide whether it's worth the effort.
What you will learn
- Narrow a broad interest into a specific question
- Define variables, measures and population
- Judge a question's feasibility and value before starting
Before this lesson: Designing a Fragrance Experiment
Scope of this track
You can complete this as an independent learner, using strips, small groups of adults and simple statistics. It doesn't prepare you for clinical work. Anything involving skin exposure to unassessed materials, health claims or vulnerable people needs qualified oversight. Those lie outside what you should attempt here.
Narrowing a question
| Draft | Problem |
|---|---|
| Do musks make perfume last longer? | Which musks? Last how? In what perfume? |
| Does adding musk make my citrus last longer? | Better, but how much? How measured? Detectable by whom? |
| Does 5% Habanolide extend the time at which a citrus accord is still detected on paper strips, against a control, for 12 adults? | Now testable; it also shows the limits of what you'd learn |
The last draft raises real questions. Is "detected" the citrus, or the musk? That matters, because a musk would be detected for longer even if the citrus had gone. A careful version might ask people to rate "citrus character" separately, or use a different design. Finding that kind of flaw before you begin is why you are writing this down.
The parts of a good question
- Independent variable. What you change, and at what levels.
- Dependent variable. What you measure, and on what scale.
- Controls. What stays fixed, and what you compare against.
- Population. Who it applies to. Your friends aren't a market.
- Conditions. Medium, temperature, time and dose.
- Hypothesis. What you expect, and what result would contradict it.
- Decision. What you will do or conclude under each outcome.
Operational definitions
Words like "fresh", "longer-lasting", "natural-smelling" and "premium" don't measure themselves. Say how you'll measure each one. "Fresh" might be a 0 to 10 rating anchored to a stated reference. "Longer-lasting" might be the last time point at which at least half the assessors say they can detect it. Each definition narrows what you can claim. You'd say "rated fresher on this scale, by these people", and not "fresher".
Has it been answered?
Search before you start. Check PubMed, Google Scholar, and the sources in this Academy. You may find that someone has done your study, or that a method exists, or that the literature disagrees. Your question needn't be new to the world. A careful replication can teach you a lot, and small replications are useful. Just don't claim any discovery without looking.
Feasibility and value
| Question | If the answer is no |
|---|---|
| Could a result change what you do or believe? | Choose another question |
| Can you get the materials and participants? | Narrow it, or change method |
| Can you measure it with what you have? | Change the measure, or partner with a laboratory |
| Is it safe and ethical? | Stop and redesign. See the ethics lesson |
| Could the sample size detect the effect you care about? | See the sample-size lesson |
Practical exercise: A research question file
- Write down five things you're curious about in your own perfumery.
- Choose one, and write three progressively narrower drafts.
- For your final draft, state each part from the list above.
- Define each key term operationally.
- Spend an hour searching. Note three relevant sources, or record the search terms that found none.
- Complete the feasibility table, and ask someone to find the weakest assumption.
You have done this well if someone could tell from your statement what result would prove you wrong, and your search is recorded.
Common mistakes
- Starting with a method. Start with the question.
- Asking something that can't fail. That's not a test.
- Measuring what's easy instead of what matters. State the gap, if you must.
Key terms
- Independent variable
- What the researcher changes on purpose, such as the dose of a material.
- Dependent variable
- What is measured to see if the change had an effect, such as a rated intensity or a correct identification.
- Operational definition
- An exact statement of how a concept will be measured in a particular study.
Knowledge check
Written and reviewed by the RUŌOD Lab team. This is general education, not legal, regulatory, medical or safety advice. Example dilutions and exercises are for learning, are not validated products, and have not been safety-assessed. Completing a lesson confers no qualification. How we check these lessons.