The theoretical assumptions are invalid and remain that way until proven otherwise, and they are proven valid only when tested by means of observation or experience through data collection rather than theory or pure logic.

In conducting research, data collection is a very important aspect of any research work. When data for a particular research project is collected and analyzed, it shows the conclusions of that research as a reflection of what the data revealed. Moreover, the data collected by a researcher is important in meeting the objectives or answering the questions posed by a research project.

Note that the collection of data is an important part of any research activity because the conclusions of the study are based on what the data reveals. Therefore, no researcher is greater than his data.

Basically, data can be obtained from two major sources; primary and secondary sources.

Primary data represents the information gathered by the researcher through the use of questionnaires or personal interviews or observation methods; while in secondary data, the researcher collects information that has already been obtained and processed by government departments or various agencies before it is made available for other interested users. These are published and unpublished sources e.g. journals, textbooks, newspapers, magazines, flyers, annual reports, bulletins, periodicals, etc As a result, the kind of data to be collected, the method of collection to be used, and the scoring of the data must be considered when undertaken any research activity.

Types of Data to be Collected

Researchers can collect the following types of data from respondents:

    Demographic information or data e.g. age, sex, gender, educational background, ethnicity, religion, etc     Test scores     Events     Responses to researchers questions in an interview or written replies to a survey question     Grade point averages obtainable from school records     The essay is written by students e.g. projects, theses, and dissertations.     Anecdotal records kept by teachers or counselors or researchers.

In fact, the list of data to be collected is not limited to the one listed above. For this reason, it is important for every researcher to decide on what kind(s) of data he or she intends to collect and by what method to collect it. Those methods that researchers use in collecting his desired data are known as research or measurement instrument.

Data Collection Instruments

These are instruments that are used to collect data from participants of the study. They are important for collecting data in all types of research methods. They are mainly used by researchers to collect reliable data which will later be analyzed (Aina, 2004). They include questionnaires, interviews, observations, focus group discussions, and experiments. Each of the instruments shall be discussed in turn and also point out their merits and demerits.


The questionnaire is a commonly used instrument for collecting research data from the participants of a study. “It basically seeks the opinions of individuals in a sample or a population on issues directly related to the objectives of the research study” (Aina, 2004:348).

The questionnaire consists of a set of structured and unstructured questions designed by researchers to obtain data from the respondents. No research is better than its questionnaire and a faulty questionnaire means faulty research. Hence, a questionnaire designed must be valid, reliable, and must not be bogus so that the data collected can validate the research.

The questionnaire has many advantages which include anonymity of the respondents is guaranteed; it facilitates the collection of large amounts of data in a relatively short period and it is cheap to administer. The major demerit of the method is that some confusing and misleading questions cannot be clarified as the researcher may not be there to explain the questions, and also, sometimes, the questions may not be easily comprehensible to individuals who are illiterate, thus, the method is restricted only to educated respondents.

Moreover, the characteristics of a good questionnaire according to Popoola (2011) consist of:

    Questions should not be ambiguous. This implies that it must be capable of only one interpretation.     Questions must be easily understood.     Questions should be capable of having a precise answer.     Questions must not contain words of vague meaning.     Questions should not require rigorous calculations.     Questions should not require the respondent to decide upon classification.     Questions must not be in such a form that the answers will be biased.     The questionnaire should not be too long.     It should not be too wordy.     The questionnaire should cover the exact object of the inquiry.


An interview is a measurement instrument otherwise known as an oral questionnaire. It involves a process where a researcher solicits information from respondents through verbal interaction. A researcher would have previously prepared a schedule list of structured questions pertinent to the study before meeting respondents for their opinions on a subject matter.

The researcher poses questions to the respondents and the answers are recorded by the researcher. Materials that could be used during the interview period include a tape recorder, paper, and biro. The major advantage of this method is that it produces a high response rate. Besides, it tends to be representative of the entire population of the study, and personal contact between the researcher and respondents enables the researcher to explain confusing and ambiguous questions in detail (Aina, 2004; Popoola, 2011). However, its disadvantages include the interviewer’s bias; inaccessibility to wealthy respondents due to fear of insecurity and the amount of data that can be collected through this method is usually limited compared to the questionnaire method. The interview can be conducted personally or through telephone or electronic mailing system.


This is an instrument that is employed by a researcher in which an individual behavior or situation is observed and recorded. There are two types of observation: participant observation and non-participant observation. In participant observation, the researcher is a member of the group to be observed. Here, the accurate and timely results would be obtained by the researcher but it has the problem of business. Non-participant observation, on the other hand, the researcher is not a member of the group to be observed. Here, the result will be viable as it is free from being biased but it has the problem of inaccuracy and delayed result. Both observation methods enhance first-hand information, flexible and cheaper to carry out, demand less active cooperation of the observed and their results are reliable for research activity.

However, Akinade & Owolabi (2009) assert that an observation method is a popular tool in research especially in behavioral and social sciences; the authors argue that it requires special skills to make and assess behavioral observation in research. In carrying out a behavioral observation, the first thing to do is to develop behavioral categories (coding scheme). This involves identifying specific attributes that will give clues to the problem at hand. The authors further reiterated that researchers may observe the following guidelines when developing an observation method:

    “Clearly define the goal of the instrument;     Carry out preliminary observations of your subjects under the conditions that will prevail in the course of the study with the aim of identifying behaviors exhibited by the subjects; and     Construct a complete list of the identified behavior. Also, behavioral categories can also be developed through a literature search. These will provide an opportunity to determine whether a similar study had previously been conducted. The result of such a similar study may be adopted or adapted in the present study” (Akinade & Owolabi, 2009:97).

Focus Group Discussion

This data collection instrument refers to a process whereby researchers obtain data from a large group of people at the same time. This method is different from the interview method; in an interview method, the researcher focuses on one person at a time but in a focus group discussion method, the researcher obtains data from a large number (group) of people for his research activity. The Focus group discussion method is very popular when carrying out research in the field of behavioral science, library and information science, archival science, records, and information technology. It could be noted here that a need may arise for a researcher to use more than 2 or 3 approaches to obtain data for his research activity. This depends on the supervisor, nature of the research, or problem to be investigated.

However, in focus group discussion; a researcher identifies key informants that may be contacted to elicit the deserved information on the variable(s) of interest in a study. It is very important to note that in an evaluator study or when accessing the performance of a system or a project or when working at a policy and its impact on a particular operation in a society or organization; the focus group discussion method could employ. The approach is used to generate qualitative data in explaining a phenomenon under study or investigation. Membership of the focus group discussion should not exceed 10 members at a time. It is like a mini-conference where members of a group could be assembled in a conducive location. Before now, it is needful for the researcher to have obtained their consent to take part in the study.

Besides, the researcher must design a focus group discussion guide. The guide must contain outlines that capture variables of interest in the study. For example, in a study like: “Customers’ satisfaction with information services or products of Babcock university library”. The following guidelines may be prepared by the researcher:

    Nature of the library services;     Nature of the products;     Level of satisfaction of the users;     Quality of the users, etc.

The following materials are needed for this method of data collection:

    Research assistants;     Video recorder and cassette;     Biro and paper;     Tape recorder and cassette, and     Light refreshment to entertain the participants.

After the focus group discussion exercise, the researcher has to transcribe the data into qualitative information e.g. on the nature of reference services available in the library; in a group where 10 members are involved, if 7 members affirmed that they are having good reference services in their library while the rest members’ response is negative. Then it can be calculated/quantify as 7/10 *100 = 70%; this is the figure that the researcher will report in his work. Moreover, the major advantage of this method is that it added credibility and originality to the research activity while it challenges include: too costly to carry out, it takes too much of time to conduct and some of the respondents may not be free to contribute extensively especially if their boss is invited to such gathering.


This type of data collection instrument takes place in pure and applied science research. Here the researchers carry out some experiments in the laboratory setting in order to test some reactions that may take place in the object of research. The advantage of this method is that it produces immediate results, its results are viable and error-free if it is well carried out under normal conditions/circumstances. While its problems include: it is too costly to undertake and those chemicals used may cause permanent damage to the researcher if they are carelessly handled.

Table 1: Types of Research and Data Collection Instruments


Types of Research     

Data Collection Instruments



The questionnaire, Interview, and observation.



The questionnaire, focus group discussion, interview, and observation.


Case study     

The questionnaire, interview, focus group discussion, and observation.


Ethnographic e.g. correlational research     

Observation, questionnaire, focus group discussion, and interview



Observation, focus group discussion, and interview



Focus group discussion, interview, and observation


Pure science     

Experiment and observation



Questionnaire and interview



Questionnaire, observation, focus group discussion, interview, and experiment in case of pure science research.



The questionnaire, observation, and interview.

Source: Japheth Yaya, 18th June 2014


It could be re-emphasized here that researchers are not restricted only to different methods of data collection instruments and their classification as presented in this paper but the choice of which method to apply depends on the researcher, nature or problem to be investigated, and prevailing circumstances at the time of carrying out the study. Thus, researchers are free to use any method they deem fit for their research.


Adedokun, J.A. (2003). Basics of Research Methodology. Sagamu: New Hope Publisher.

Adeniyi, A.L.; Oyekanmi, A.O. & Tijani, M.O. (2011). Essentials of Business Research Methods. Lagos: CSS Bookshops Limited.

Aina, L.O. (2004). Library and Information Science Text for Africa. Ibadan: Third World Services Limited.

Akinade, E.A. & Owolabi, T. (2009). Research Methods: A Pragmatic Approach for Social Sciences, Behavioural Sciences, and Education. Lagos: Connel Publications.

Avwokeni, J.A. (2006). Research Methods: Process, Evaluation & Critique. Port Harcourt: Unicampus Tutorial Services.


Tags: Research instrument, data collection instrument,