Methods of Data Collection

Data collection is a crucial part of any research work, before you can analyse any data on a subject of study, you need to be sure that the data you are using is reliable. The reliability of data can be determined by the method through which the data was collected. The method of data collection depends on the type of data which can be either primary or secondary data. It is important to understand the differences between the two to know which method of data collection to use.

Primary data is data collected directly from the units being surveyed. This data is regarded as pure as it has not undergone any statistical analysis before. Secondary data, on the other hand, is data gotten from primary sources such as Federal Statistics Agencies, Federal Bureaus, technical journals, and so on. What differentiates these two methods of data collection is the exchange of hands after collection.

Sourcing data for research purpose requires you to put several variables into consideration. These variables include the accuracy required, the skill of the enumerator, the collection point, the purpose of the data, the sponsors of the data collection, among many others.

Generally, the methods of data collection are registration; questionnaires; interviews; reporting; and direct observations. For research purposes, however, methods of data collection have been divided along the lines of the type of data being collected. Below are some of the methods of data collection peculiar to each type of data.

Primary Data

Primary data are data collected directly by the researcher from the units being surveyed. It may be from interviewing people, observing phenomena, establishing a register, administering questionnaires, and so on. This data has never been analysed as is thus regarded as pure or original data. After collection, such data can then be published. The two basic methods of primary data collection are investigation and questionnaires.


This method can take three different forms. The first method requires the surveyor or researcher to collect the data himself/herself. It is known as personal investigation. It is a reliable form of data collection but can only be used for small projects. Another way is to employ trained investigators to carry out the data collection exercise. These investigators contact respondents and take the survey as required. The last form of investigation is the telephonic investigation. This is usually done by calling respondents over the phone to answer quick questions during which important data is collected. This can be done either by a single person or by a team of surveyors.


Questionnaires are arguably the easiest way to collect primary data. This is done by sending a set of selected questions to people on a particular subject of study. Respondents record their answers on the questionnaire, after which the survey can go back and analyse the data collected. It is a very convenient method as it can be mailed to people and results recorded electronically.

Secondary Data

Secondary data are considered impure data. This is because these data have undergone statistical treatment at least once. They are data gotten from platforms on which primary data are published. The sources of secondary data include organisations, journals, government agencies, and so on. These data can be collected and analysed by researchers for their studies. Below are some of the methods of collecting secondary data:

Publications of Official Bureaus and Agencies

Most times, primary data are collected by the government to aid in the formulation of policies and political frameworks. These data are then published on the official websites and other publications of the government in the related sector. Researchers can refer to these publications as sources of secondary data during their research. These bureaus and agencies include the National Bureau of Statistics, the Central Bank of the country, the Ministries, Agricultural Statistical Boards, and so on.

Publications of Organisations

Non-governmental and inter-governmental organisations also collect primary data, which can become a source of secondary data for researchers afterwards. Various studies are premised on data collected from organisations such as the World Health Organisation, the World Bank, the International Monetary Fund, the International Court of Human Rights, among others.

Technical Platforms

Over the years, individual researchers have carried out primary data collection which they have published on different independent platforms such as journals, newspapers, newsletters, and others.

This article is the first part of two; the second part would be released shortly.