What does “measurement” mean?

We propose to start this module by reflecting on the following research question: “Which factors influence the performance of high school students on their graduation exam?” Each of you have some thoughts about the factors based on your personal experience as a former high school student. Thus, you might mention such factors as: gender, educational achievement, family background, residence, health status, risky behaviour, etc. The impact of these factors on school success are well documented in scientific literature in the field of education. In 2015, we identified a research gap while investigating this question. Considering that during adolescence, youth engage in romantic and intimate relationships, we nevertheless found no previous study looking at the influence of this factor on the school achievement (Dégi and Faludi, 2015). Now let’s say that in approaching this research question you decided to collect data through a sociological survey, using a self-administered online questionnaire applied to high school students from your locality. When you design the questionnaire, you must answer the crucial question: “How will I measure most appropriately the aforementioned factors and the outcomes influenced by these factors?”

Before proceeding to the effective measurement, let’s introduce the term “variable”, which is a trait, a characteristic, or an attribute possessed by the statistical individual, which presents variations in the studied sample or population, and it is of interest for the researcher. In our example, the statistical individual is the high-school student, and its characteristics are variables, as we know that there is variation among high school students in terms of their school grades, family background, health status, etc.

The process of measurement means to establish for each variable involved in the research its exact meaning, and this procedure is called conceptualization. In the mentioned study (Dégi and Faludi, 2015), the authors agreed on the following specifications for some of the investigated variables: for educational achievement – whether the student had to re-take any of the examinations in the last semester of the 12th grade; for family background – whether the family of origin had a low socio-economic status, for residence settlement – place of residence at present, for health status – self-rated health, for risky behaviours – consumption of illegal substances, for intimate relationship – type of relationship with the partner at the time of the first sexual intercourse. Also, the conceptualization of the performance during the graduation exam assumes an exact description of this form of evaluation. In Romania, where the study was conducted, this exam is called Baccalaureate, a compulsory nationwide examination held when students graduate from secondary education, called Liceu (the equivalent of high school), after 12 years of studies in total. Baccalaureate is a single degree qualification test based on 10-point scale grading system (with a pass mark of 6), and it is compulsory for the admission exam at the university.

The next step of the measurement process is to operationalize each variable. Operationalization means to settle the precise procedures used to measure the attributes of each variable. In other words, operationalization involves specifying the range of variation of variables, deciding on the appropriate level of measurement--an aspect which will be detailed in the next section of the module. We continue using the same example: the operationalization of investigated variables was made to respond to the rigors of the multivariate analysis. Thus, for the variables 'whether the student had to re-take any of the examinations in the last semester of the 12th grade', and for 'whether the family of origin had a low socio-economic status', and for 'the consumption of illegal substances' – the variation of answers was reflected by dichotomic answer of no or yes; for gender – the answers were female and male; for place of residence at present the choices were urban and rural; for self-rated health the answers varied from very good, fair and poor; and for the relationship with the partner at the time of the first sexual intercourse the authors distinguished between steady versus occasional relationship. Of course, the conceptualization implies that the researchers specify exactly what a steady relationship means. For instance, in this case, an intimate relationship was defined as steady if the two partners were together at least 3 months before the first intercourse. Performance at the Baccalaureate exam was conceptualized using two variables: taking the Baccalaureate examination (yes versus no) and the results obtained on the Baccalaureate examination (good versus bad result, established as acquiring an equal to the average grade point and over, versus under the average grade point).

Here we must underlie three points:

• First of all, you need to understand that the process of conceptualization and operationalization is a challenging one, as when you work on specifying what your concepts mean, you will encounter disagreements and inconsistencies, caused by the different ways of defining the concepts among researchers. Therefore, in each study, you have to find the best suitable definition of the variables and their variations according to your research questions or hypothesis before conducting your survey, as you will not have a second chance to correct the way in which you measure the concepts of interest.
• Second, the process of conceptualization and operationalization continues after the collection of data. The authors of the exemplified study also applied this procedure. Here there are two examples: in the questionnaire, performance at the graduation exam was measured by the exact grade point obtained at the Baccalaureate and the socio-economic status of family was investigated using the indicators of the material deprivation rate used by Eurostat. As we already mentioned, the authors recoded the answers in order to prepare and use them in the statistical modeling.
• Third, it is important to keep in mind that with progress of science and with transformation of societies, researchers will continue to re-conceptualize and re-operationalize the most important concepts, as they continuously seek for more useful  and accurate measures. To give you an example, with the widespread of the new living arrangements in the post-modern societies, in the operationalization of the variable type of living arrangement, we should not neglect a newly documented form of living – the LAT or living apart together – quite common among Italian young people. Also, the term spouse was replaced with that of partner, as marriage is considered nowadays one of the possible living arrangements, but it is not expected in everyone’s the life-course.

We will continue to advance in our module by explaining two other concepts – independent and dependent variables, while invoking the same study. You recall we mentioned the gap in the research the authors identified: The authors assumed that there might be an association between the context and the performance at the Baccalaureate. In the methodology of quantitative research, we call this statement a research hypothesis. Here, and in other studies, the researchers are interested in seeking a relationship between two or more variables, one of them called dependent variable, and the other/s named independent variable/s. The dependent variable is the one we wish to explain in our research study, whose variations represents the effects of the independent variable/s, referred to as factors. In this example, the graduation at the Baccalaureate and the result at this examination is the dependent variable, and these may depend, among other factors, on the type of relationship with the intimate partner, which is the independent variable. The results of the multivariate analysis not only confirmed this hypothesis, but demonstrated that the type of relationship with the partner at first sexual intercourse was the most important factor on school performance. To be clearer, it has been proven that high school students who began their sexual life with an occasional partner were almost three times more likely to fail at Baccalaureate and more than five times more likely to obtain poor results at this examination. Although the questionnaire was completed by a relatively small number of respondents – 401 high-school students – such result might have an impact on the educational policy, when educators intend to plan programs aimed at the improvement of school performance.

Returning to the discussion about the dependent and independent variables, there is one more important detail to mention. You should understand that a given variable is referred to as dependent or independent based on the focus of investigation in a given research study (Weinbach and Grinnell, 2010). For example, the performance at the Baccalaureate was the dependent variable in the presented study, but could become the independent variable in a study which explore the influence of the result at the Baccalaureate on the result at the admission exam in the university.