Deductive Reasoning

There are two reasoning styles widely used in research methodology, deductive reasoning and inductive reasoning. Deductive reasoning is associated with Positivism or scientific study approach. This style of reasoning is based on hypothesis testing. Positivism is a research philosophy that studies the social world using scientific method. Quantitative research is based on positivism and deductive reasoning. Furthermore, Quantitative research involves quantitative variables that can be measured and quantified through counting or using measurement units.

Deductive reasoning has been derived from the root word “deduce”. According to Cambridge Dictionary , the meaning of ‘deduce’ is “to reach an answer or a decision by thinking carefully about the known facts”. Hence, it means that deductive reasoning is based on interference of known facts, laws, and general principles.

Deductive Reasoning: A Theory-Testing Approach

Deductive reasoning is a theory testing approach. This approach is used to test a theory by collecting quantitative data to validate a hypothesis. A hypothesis is a tentative statement that can be tested. However, Deductive reasoning develops a hypothesis from existing theories and tests the hypothesis to make a decision. For example, considering Herzberg’s Hygiene-Motivation theory, it can be said that employee recognition has a positive effect on employee motivation. This statement is a hypothesis to be tested using data collected from samples using a structured questionnaire consisting of close ended questions. Findings of quantitative analysis will validate the alternative hypothesis or null hypothesis.

Deductive Reasoning in Applied Research

Deductive reasoning is used widely in social sciences and natural sciences. Quantitative research is used to validate hypothesis using primary or secondary data. Similarly, Deductive reasoning is used in applied research. In other words, Applied research is interested in applying existing theories to solve problems and development of knowledge.

General to Specific Approach

Deductive reasoning is known as general to specific approach. A general theory is used to develop hypothesis. This hypothesis is tested using data collected from samples of a specific population. However, Deductive reasoning improves the confidence in research by improving reliability of the research. The confidence and reliability in research increase if it produces similar results in different contexts and environmental settings. It is also known as top to bottom approach because the study starts with a theory and ends at confirmation or rejection of hypothesis derived from the theory.

Limitations in Qualitative Research

Deductive reasoning is used in causal research, also known as cause-and-effect study. Such research focuses to investigate relationship between variables and effect of change in an independent variable on dependent variable. Deductive reasoning cannot be applied to qualitative research. Following are the main differences between deductive and inductive reasoning

Deductive Reasoning : Examples

Some examples of Deductive Reasoning are:

• Known: An increase in financial reward increases employee motivation
• Known: I have full time employees working in my organization
• Deduction: An increase in financial reward of employees working in my organization will increase their motivation

• Known: All fish have gills
• Known: Shark is a fish
• Deduction: Shark has gills

• Known: A is equal to B
• Known: B is equal to C
• Deduction: A is equal to C

Inductive Reasoning

Inductive reasoning is opposite to deductive approach. As mentioned above, deductive reasoning is theory testing approach, inductive reasoning is a theory building approach. Inductive reasoning is also known as “Bottom-up approach”. Therefore, Such reasoning is based on observations collected from a specific sample and developing a general conclusion that can be applied to entire population. Inductive reasoning is used widely in social science in qualitative research. However, Inductive reasoning is not used to perform quantitative analysis to confirm or reject hypothesis. On the contrary, inductive reasoning helps to understand a process, object, or any other phenomenon in detail.

Theory Building and Qualitative Research

Inductive reasoning is used in studies that are based on research philosophy of interpretivism. Inductive reasoning cannot be aligned with the positivism. Positivism uses quantitative data and confirms or rejects a hypothesis. Interpretivism goes beyond quantitative data and pays attention to the context or background of data. In inductive reasoning, “why” and “how” is more important. For instance, as mentioned in an example above, an increase in financial reward increases motivation of employees. This statement is a known fact based on deductive reasoning. Inductive reasoning is more interested to find answers to questions such as “why does an increase in financial reward increase employee motivation?” Therefore, inductive reasoning helps to understand the underlying concepts, assumptions, beliefs, and ideologies.

Is Inductive Reasoning better than Deductive Reasoning?

There is no competition between Deductive and Inductive Reasoning. Both styles of reasoning have their own pros and cons. It is the reason that one approach cannot be preferred to another. In reality, both types of reasoning are used in research and complement each other. For example, inductive reasoning is mostly used in exploratory and descriptive research. These are types of basic research to understand a phenomenon or process to increase knowledge. However, such research is qualitative and lack reliability and validity. Deductive reasoning strengthens an argument and provides empirical evidence. Deductive reasoning confirms or rejects hypothesis that has been developed based on findings of inductive reasoning. Therefore, both types of reasoning are used in research to develop theories and arguments.

Example:

Let us consider the example of the pandemic of Covid-19. When the pandemic started, little or no knowledge was available to understand the damage caused by the virus and behavior of the virus. Although, Researchers used inductive reasoning to start learning about the virus from different observations. Such as, Temperature of the patient, common symptoms, risks, and effects of medication on health of employees were different observations that improved knowledge and understanding of the virus. However, Blood samples, prescriptions of patients, patients under observation in ICUs, and many other sources of observation and information were used to perform research.

Inductive reasoning provided data using observations from specific samples and developing conclusions about population. However, deductive reasoning was used to develop various hypothesis developed from findings of inductive reasoning. For example, using inductive reasoning, it was found by doctors and health experts that patients who used Vitamin C showed a faster recovery rate. Using deductive reasoning, a hypothesis was developed.

• H₁: Patients suffering from Covid-19 who consumed Vitamin C have a faster recovery rate
• H₀: Patients suffering from Covid-19 who consumed Vitamin C do not have a faster recovery rate

Patients were divided into two groups. One group of patients consumed recommended dosage of Vitamin C and the other group was not consuming Vitamin C at all. Findings of the research showed that Vitamin C helps in quick recovery because it strengthens the immunity system. There was a strong correlation between consumption of Vitamin C and time taken to recover from Covid-19. This example shows how inductive and deductive reasoning help in evolution of knowledge by understanding processes, taking observations, developing hypothesis, doing data analysis, and reporting findings to develop conclusion.

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