Data collection is a fundamental stage of research because the quality of the findings largely depends on the quality, accuracy, relevance, and reliability of the data collected. In research methodology and statistical analysis, data collection refers to the systematic process of gathering information from appropriate sources to answer research questions, test hypotheses, identify relationships, and support scientific conclusions. Data may be collected in numerical or non-numerical form depending on the nature and objectives of the study. Broadly, data are classified into primary data and secondary data. Researchers select data collection methods according to the research problem, population, resources, time available, and required level of accuracy. Primary data are original data collected directly by the researcher for a specific research purpose. These data have not previously been collected or processed for another study. Common methods of collecting primary data include observation, interviews, questionnaires, schedules, experiments, focus group discussions, and surveys. Observation is one of the oldest and most direct methods of data collection. In this method, the researcher systematically observes the behaviour, activities, events, or conditions relevant to the research problem and records the observations. Observation may be participant or non-participant, structured or unstructured, and controlled or uncontrolled. Participant observation involves the researcher becoming part of the group being studied, whereas non-participant observation involves observing without participating. This method is particularly useful in social sciences, behavioural studies, market research, and field studies because it can capture actual behaviour rather than relying entirely on respondents' statements. The interview method involves obtaining information directly from respondents through verbal interaction. Interviews may be structured, semi-structured, or unstructured. In a structured interview, predetermined questions are asked in a fixed order, making responses easier to compare statistically. Semi-structured interviews provide a balance between standardization and flexibility, while unstructured interviews allow respondents to express their views freely. Interviews can provide detailed and qualitative information and are especially useful when the research requires explanations, opinions, experiences, or attitudes. However, they can be time-consuming and may be influenced by interviewer bias. Questionnaires are another widely used method of primary data collection. A questionnaire consists of a series of written questions that respondents answer