What's the difference between inductive vs. deductive research?

Do you check the current weather report to decide whether to wear a coat? Have you watched a detective show and tried to figure out who did it?

If so, you've used inductive and deductive reasoning. Both these methods are used in everyday decision-making and in scientific research to form hypotheses and test theories.

In logic, inductive and deductive reasoning are two forms of argumentation. Inductive and deductive research are two methods that apply these argument types to questions about the world.

The major difference between inductive vs. deductive research methods is whether the research tests a hypothesis (an educated guess) or a theory (a hypothesis that has been tested many times).

Inductive Research

• It's used to form or test a hypothesis.

• Specific observations lead to a general conclusion.

• Researchers start with the expectation that the hypothesis might not be true.

• A conclusion becomes more reliable the more times the experiment is performed.

Deductive Research

• It's used to test a theory.

• A general theory is used to explain specific situations.

• Researchers start with the expectation that the theory is true.

• A conclusion is usually, but not always, predictable based on previous testing.

Specific research models aren't purely inductive or deductive. Researchers in many disciplines often use both types of reasoning together in the same study.

An inductive approach is necessary when you're observing a pattern that doesn't have an established theory to explain it.

Suppose you eat at a restaurant, and the cheese pizza has been excellent the last three times you ordered it. You might conclude that the next time you eat cheese pizza there, it will taste great.

Inductive research leads to a probable but not certain conclusion since you're only observing a limited sample. Repeated testing will back up or refute the generalization that the cheese pizza at that restaurant is always great.

Photo by Ivan Torres on Unsplash

A hypothesis becomes more reliable with repeated observations.

You know that the sun will rise the next morning based on your prior experience. While it's possible that this conclusion is untrue, it's highly unlikely since observations over thousands of years have confirmed that the sun will rise the next morning.

Since the hypothesis that the sun rises every morning has been tested extensively, it's now a theory.

Example in Research

Researchers conducted a study on how screen time habits impact adolescents' sleep quality.

They hypothesized that adolescents who share a room with other family members may consume more media at night and have trouble sleeping as a result. After comparing study results from thousands of participants about their screen time and sleep habits, the authors concluded that screen time before bedtime does indeed have a negative effect on sleep.

Based on these findings, they recommended healthier screen time options for improved sleep.

Deductive research starts with an established theory or belief, which means the results of the study are predicted before the study even begins. Natural laws, such as inertia and gravity, are examples of theories.

Why perform a deductive study if the results are predictable? A deductive study may end up disproving a theory, or the theory may need to be modified based on new evidence. Researchers might apply a theory in a different context, which requires a new study.

Photo by Kelly Sikkema on Unsplash

Example in Research

Music therapy is an established practice, and its benefits are well-studied. Based on prior research, the authors of a particular study started with a theory (that is, music decreases epileptic seizure frequency) and then tested it by examining the effects of music therapy on patients.

Since many other studies use Western classical music in music therapy, the authors added to the previous research by observing the effectiveness of other musical styles.

Note that the theory was first formed by inductive research and then tested by deductive research, when it was either confirmed or disproven through the research results.

Which research study is inductive?

1. Researchers start with the belief that a newly approved allergy medication will relieve allergy symptoms. They then observe how participants are affected by the medication.

2. In an observational study, researchers search for a pattern in the relationship between salt consumption and high blood pressure.

3. After conducting market research, a company introduces a new sugar-free soft drink, and then tracks its sales to see if it’s as popular as the company expected.