How to Choose the Right Measurement Instrument

Measurement instrument refers to various methods through which a researcher obtains data from respondents for his research work. The term data refers to all forms of information that researchers obtain from the participant of the study. Adedokun (2003:57) asserts that data refers “to any fact, observation or facts relating to the subject of the study”. There are different types of measurement instruments that can be used by researchers for their studies; it depends on the nature of research that is to be carried out. In this write up, we shall discuss various measurement instruments that can be used alongside with studies that are suitable for them.

 
However, the collection of data is an important part of any research activity. This is because; the conclusions of the study are based on what the data reveals. Hence, 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 questionnaire or personal interview or observation method; 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 These are published and unpublished sources e.g. journals, textbooks, newspapers, magazines, fliers, annual reports, bulletins, periodicals etc As a result, the kind of data to be collected, the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
According to Aina, 2004; Adedokun, 2003; Avwokeni, 2006; Adeniyi; Oyekanmi and Tijani, 2011. Researchers can collect the following types of data from respondents:

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 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 questionnaire, interviews, observations, focus group discussion and experiment. Each of the instruments shall be discussed in turn and also point out their merits and demerits.

The questionnaire is the 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.

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:

Interview is a measurement instrument otherwise known as 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 interview period include tape recorder, paper and biro. The major advantage of this method is that it produces 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 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 compare to questionnaire method. 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, accurate and timely result would be obtained by the researcher but it has the problem of biasness. 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 carryout, demand less active cooperation of the observed and their results are reliable for research activity.

However, Akinade & Owolabi (2009) assert that observation method is popular tool in research especially in behavioural and social sciences; the authors argue that it requires special skills to make and assess behavioural observation in research. In carrying out behavioural observation, first thing to do is to develop behavioural 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 observation method:

This data collection instrument refers to a process whereby researchers obtain data from large group of people at the same time. This method is different from interview method; in an interview method, researcher focuses on one person at a time but in a focus group discussion method, the researcher obtains data from large number (group) of people for his research activity. Focus group discussion method is very popular when carrying out research in the field of behavioural 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 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; focus group discussion method could employed. 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:

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

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 are 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 cost 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 advantages of this method is that it produces immediate result, its results are viable and error free if it is well carry out under normal condition/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.

Table1: Classification of Research Based on Data Collection Instruments

 Conclusion
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.

References
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. Portharcourt:         Unicampus Tutorial Services.