Understanding Variables: Types, Roles, and Measurement
1. What is a Variable?
A variable is a property that can vary and whose range is capable of being measured.
2. Types of Variables
- Quantitative or Numerical Variable: A variable that can be measured numerically.
- Qualitative or Categorical Variable: A variable that can only be classified into categories.
- Nominal Variable: Indicates a property without any inherent order (e.g., names, gender).
- Ordinal Variable: Possesses an order between the values (e.g., low, medium, high).
- Dichotomous Variable: Attributes are observed in only two categories (e.g., sex: female/male).
- Polychotomous Variable: Attributes are observed in more than two categories (e.g., marital status: widowed, divorced, cohabiting, single).
3. Roles of Variables in Research
- Independent Variable (or Control Variable): Explanatory variables whose association or influence on the dependent variable is intended to be discovered.
- Dependent Variable (or Resulting Variable): The factor that is observed and measured to determine the effect of the independent variable.
- Intervening Variable (or Mediator): Characteristics or properties that affect the expected outcome and are associated with both independent and dependent variables.
- Confounding Variable (or Extraneous Variable): A factor that distorts the effect of a study variable on the outcome, which the researcher must avoid.
- Random Variable: A variable whose values arise due to random factors (by chance), allowing for inference.
4. Research Types and Variable Roles
- Descriptive or Observational Research: Variables are described and accounted for, potentially revealing relationships between them.
- Analytical or Explanatory Research: In addition to describing variables, the cause-and-effect relationship is investigated without intervening, only observing.
- Experimental or Predictive Research: Similar to analytical research, but the independent variables are manipulated, and the dependent variables are measured as a result of the intervention.
5. Operationalization of Variables
Operationalization is the process of moving a variable from an abstract level to an operational level. It involves specifying the meaning or scope of a variable and explaining how it will be measured.
6. Identification of Variables
The main variables are identified from the problem definition and objectives and continue to be refined in the theoretical framework, where secondary variables are identified and conceptualized.
7. Dimensions, Indicators, and Items
- Dimensions: General and abstract concepts that need to be broken down into more specific, measurable components.
- Operational Definition of Dimensions: Describes the activities an observer must perform to receive sensory impressions called indicators.
- Indicators: Direct observations derived from dimensions, which can be measured and transformed into items or values.
- Item: A statement, often written as a question, used for observation or measurement. Responses are analyzed and assigned numerical values.
- Index Numerical Values: Numerical values obtained from an item, expressed in numbers for numeric variables or assigned numbers for categorical variables.
- Coding: Converting numerical values to qualitative categories through grouping intervals.
8. Measuring Variables
Measurement is the assignment of numerals to objects or events according to specific rules.
9. Measurement Scales of Variables
- Nominal Scale: The most basic level, involving classifying objects into categories.
- Ordinal Scale: Classifying objects or events hierarchically based on the degree of a characteristic, without indicating the magnitude of differences.
- Interval Scale: Used for continuous quantitative variables, allowing for various statistical techniques.
- Ratio Scale: The highest measurement level, possessing the features of an interval scale with an absolute zero, enabling the determination of proportions between values.
10. Research Objectives
- Function in Research Design:
- Guide other phases of the research process.
- Determine the limits and scope of the study.
- Define the steps required by the study.
- Place the study within a general context.
- Provide guidance on the results to be obtained.
- Criteria for Formulation:
- Should be directed to the basic elements of the problem.
- Must be measurable and observable.
- Should be clear, precise, and internally consistent.
- Should be concrete and less abstract.
- Should follow a methodological order.
- Must be expressed in infinitive verbs.
- Types of Objectives:
- Research Objectives: Indicate the impact sought from survey results.
- Research Objectives: Relate to the desired consequences in medical or social practice.
- Research Objectives: Linked to the problem and research hypotheses, focusing on the variables under study.
Building Research Objectives
Research objectives should be tailored to the variables under study and the desired outcomes. They should be derived from the study type, presence of comparison groups, subject selection criteria, data management, and statistical tests. It is advisable to adopt a hierarchical approach, starting with one or two general objectives and then specifying more detailed objectives as needed. The chosen verb should be clear and unambiguous, aligning with the taxonomy to ensure the achievement of the proposed goal.