Breaking down the question
The instruction "illustrate with example" is a firm directive: an answer without a concrete worked example cannot score well, however sound its definitions. The task is to explain what variables are, distinguish their main types, and show through an example why they are significant for sociological research.
A variable is any concept or characteristic that can take different values across cases — age, income, religiosity, suicide rate. Their significance lies in the fact that empirical research proceeds by identifying variables, stating relationships between them as hypotheses, and testing those relationships against data. Our notes on research methods in sociology set variables within the wider logic of enquiry.
At 10 marks, keep the typology tight and let one good example carry the weight of the "significance" part.
How to approach it
Open by defining a variable and contrasting it with a constant, then set out the principal types — independent, dependent, intervening and control variables — in a sentence or two each.
Next, explain their significance functionally: variables allow abstract concepts to be operationalised and measured, permit hypotheses to be framed as relationships, make testing and comparison possible, and help distinguish genuine causation from spurious correlation through control.
Then supply a sustained example — Durkheim's study of suicide is ideal — showing the independent and dependent variables at work, and close by noting that careful handling of variables is what makes sociology empirical rather than speculative.
Model answer
A variable is any characteristic or concept that can vary — that can take different values from one case to another. Sex, age, income, level of education, degree of religious integration and the suicide rate are all variables, because they differ across individuals, groups or societies. A characteristic that does not change is a constant. Variables matter because empirical sociological research works by measuring them and examining how they relate to one another.
Sociologists distinguish several types. The independent variable is the presumed cause, the factor thought to produce an effect. The dependent variable is the effect, the outcome that varies in response. An intervening variable lies between the two and helps explain the link, while control variables are those the researcher holds constant in order to isolate the relationship of interest. For example, if we study the effect of education on income, education is independent and income dependent; if the true driver were family background, we would treat that as a control variable to check whether the original relationship still holds.
The significance of variables can be seen in four connected functions. First, they make measurement possible. Abstract concepts such as "social integration" must be operationalised — translated into indicators that can be observed and given values — before they can be studied at all; the variable is the bridge between concept and evidence. Second, they allow hypotheses to be framed. A hypothesis is essentially a proposed relationship between an independent and a dependent variable, stated so that it can be tested. Third, they permit that testing, comparison and, where appropriate, quantification, so that claims can be confirmed or refuted by data rather than merely asserted. Fourth, by identifying and controlling for additional variables, the researcher can distinguish genuine causal relationships from spurious correlations.
Durkheim's classic study of suicide illustrates all of this. His dependent variable was the suicide rate, treated as a social fact varying across groups. His key independent variable was the degree of social integration. By comparing rates across religious communities, he found that Protestants had higher suicide rates than Catholics. Religion here functioned as an indicator of integration: the more tightly integrated Catholic community exerted stronger social bonds and control, lowering the rate, whereas the more individualistic Protestant faith left members less integrated. To guard against alternative explanations, Durkheim controlled for factors such as nationality, region and economic conditions, showing that the association between low integration and high suicide persisted. Through the disciplined use of variables he transformed a seemingly individual and psychological act into a measurable social phenomenon with an explicable pattern.
The example shows why variables are indispensable. They convert vague ideas into researchable form, allow relationships to be stated and tested, and, through controls, help establish causation rather than mere coincidence. Handled carelessly, however, variables can mislead — a correlation may be spurious, and poor operationalisation can measure something other than the concept intended. Their proper use is therefore central to sociology's claim to be an empirical, evidence-based discipline.
Examiner's perspective
The single most common failing on this question is to define the types of variable competently and then offer no example, or only a throwaway one. Because the question says "illustrate with example", a sustained illustration — Durkheim's suicide study serves perfectly — is where the marks are won.
Examiners look for the correct pairing of independent and dependent variables within the example and, at the higher band, an awareness of control variables and the correlation–causation problem. A closing line linking the disciplined use of variables to sociology's empirical status shows the examiner that you grasp not just what variables are but why they matter.