Types of Research: Detailed Classification

Introduction

The classification of research helps the researcher choose the most appropriate approach for studying a specific problem. There are many criteria by which research can be classified: by purpose, by depth of coverage, by manipulation of variables, by type of reasoning, by time horizon, by sources of data, and by the method of obtaining them. Understanding these types is the foundation of competent research design.

1. By Purpose of Research

Theoretical (Fundamental) Research

Theoretical research (Basic / Pure Research) aims to expand knowledge and develop theories without an immediate practical purpose. Its goal is to understand the nature of a phenomenon, reveal patterns, and construct conceptual models.

Examples:

• Studying the influence of social networks on the formation of adolescents’ identity
• Researching the relationship between the type of organizational culture and the level of employee creativity
• Analyzing decision-making mechanisms under uncertainty

The results of fundamental research are published in academic journals and form the foundation for future applied research.

Applied Research

Applied research is aimed at solving a specific practical problem. The researcher seeks to obtain results that can be directly used for decision-making.

Examples:

• Developing a strategy to reduce employee turnover in a specific company
• Assessing the effectiveness of a marketing campaign for a new product
• Determining the optimal location for a new branch office

2. By Depth of Coverage

Descriptive Research

Descriptive research answers the questions “what?”, “who?”, “where?”, “when?” It records the characteristics of a phenomenon without explaining the causes. For example, a population census, describing the demographic profile of a company’s clients, or analyzing the frequency of using a particular product.

Exploratory Research

Exploratory research is conducted when a problem is insufficiently studied. Its goal is initial familiarization with the phenomenon, formulation of hypotheses, and identification of variables for further study. Qualitative methods are used: interviews, focus groups, case studies.

Correlational Research

Correlational research measures the degree of association between two or more variables. It does not establish causal relationships but only determines whether a statistical association exists. For example: “Is there a relationship between employees’ level of education and their productivity?”

Explanatory Research

Explanatory research aims to establish cause-and-effect relationships. It answers the question “why?” and requires strict control of variables. For example: “Does a mentoring program reduce employee turnover?”—while the researcher controls for other factors that may influence the outcome.

3. By Manipulation of Variables

Experimental Research

The researcher deliberately manipulates one or several independent variables and observes their influence on the dependent variable. Participants are randomly assigned to experimental and control groups. Example: testing two versions of a website (A/B testing) to determine the most effective design.

Non-Experimental Research

The researcher does not manipulate variables but observes and measures them in natural conditions. This includes surveys, observations, and the analysis of existing data. Example: studying employee satisfaction without any intervention.

Quasi-Experimental Research

A quasi-experiment is similar to an experiment, but without random assignment of participants to groups. The researcher uses pre-existing groups. Example: comparing the learning outcomes of students in two existing classes, one of which uses a new method.

4. By Type of Reasoning

Deductive Approach

Moving from the general to the particular: the researcher starts with an existing theory, formulates a hypothesis, and tests it on empirical data. If the data confirm the hypothesis, the theory receives additional support. This is typical for quantitative research.

Inductive Approach

Moving from the particular to the general: the researcher gathers data, identifies patterns, and on their basis formulates theoretical generalizations. This is typical for qualitative research. Example: based on interviews with successful entrepreneurs, the researcher derives general principles of a successful startup.

Hypothetico-Deductive Approach

A combined approach encompassing seven stages: (1) observation, (2) preliminary data collection, (3) theory formulation, (4) hypothesis formulation, (5) data collection, (6) data analysis, (7) confirmation or rejection of hypotheses. This approach combines elements of induction and deduction and is one of the most widespread in the social sciences.

5. By Time Horizon

Longitudinal Research

Data are collected at several points in time to track changes and trends. Example: annual monitoring of employee satisfaction over five years. Advantages: opportunity to study dynamics. Drawbacks: high costs, duration, risk of participant attrition.

Cross-Sectional Research

Data are collected at one point in time—it is a “snapshot” of the situation. Example: a one-time survey of clients about service quality. Advantages: speed and cost-efficiency. Drawbacks: inability to study changes over time.

6. By Sources of Data

Primary Data

Data collected by the researcher themselves for a specific study: questionnaires, interviews, observations, experiments. Advantages: data precisely correspond to research questions. Drawbacks: high time and resource costs.

Secondary Data

Data collected by other researchers or organizations for other purposes: statistical databases, company reports, archival documents, publications. Advantages: saving time and resources. Drawbacks: data may not fully match the current research.

7. By Method of Data Collection

Documentary Research

Based on the analysis of existing documents: reports, minutes, publications, archival materials. The researcher works with already recorded information.

Field Research

Data are collected in natural conditions: in workplaces, in stores, in schools. The researcher observes the phenomenon in a real context.

Laboratory Research

Conducted in controlled conditions where the researcher can isolate variables and minimize the influence of external factors. Ensures high internal validity but may suffer from low ecological validity.

Practical Assignments

Assignment 1

Question: A researcher wants to determine whether there is a relationship between the number of training hours employees receive and their level of productivity, without interfering in the work process. Determine the type of research according to three criteria: (a) by depth of coverage, (b) by manipulation of variables, (c) by method of data collection.

Solution:

• (a) Correlational—the researcher measures the association between two variables (training hours and productivity).
• (b) Non-experimental—the researcher does not manipulate variables but observes them in natural conditions.
• (c) Field—data are collected at workplaces, in a real-life environment.

Assignment 2

Question: A pharmaceutical company is testing a new drug: one group of patients receives the drug, the other—a placebo. Patients are randomly assigned to groups. Determine the type of research by purpose, by manipulation of variables, and by type of reasoning.

Solution:

• By purpose—applied, as the research is directed toward a practical task (testing drug effectiveness).
• By manipulation of variables—experimental, as the researcher manipulates the independent variable (administration of drug/placebo) and uses random assignment.
• By type of reasoning—deductive approach, as the researcher starts from a theory about the drug’s effectiveness, formulates a hypothesis, and tests it empirically.

Assignment 3

Question: Provide an example of a research question that would require a longitudinal study, and explain why a cross-sectional study would be insufficient.

Solution: Example: “How does the level of professional burnout among doctors change during the first five years of work?” A cross-sectional study would record the level of burnout only at one moment and would not allow tracking its dynamics. A longitudinal study allows observing changes among the same participants over time, revealing tendencies and turning points.