Understanding Variables and Measurement Scales in Research
Scales of Measurement of Variables
Planning time. Control is carried out methodically by exclusion criteria.
Categorical or Qualitative Variables
Rating Scale (any attribute): It has categories that you name, and there is no implicit order between them. It only identifies an event as different and allows relationships.
Ordinal Scale (an attribute – Order): Has ordered categories but does not quantify the distance between one category and another. It establishes relations of hierarchy.
Numeric or Quantitative Variables
Interval Scale (two attributes – Order and Distance): Has equal and measurable intervals. It has no real source, so it can assume a zero value. It has hypothetical/relative points that are equidistant.
Ratio Scale (three attributes – Order, Range, and Origin): You have constant intervals between values, plus a real home. Zero means the absence of the individual; the zero is real.
Measuring Instruments
Designed to measure subjective variables called constructs, require structured tasks or procedures that reflect the responses of one participant, whose score is independent of the evaluator. Instruments should provoke a reaction that is assessed, whose response is translated into a document. These are:
Documentary Instruments
Relational: There are studies of cause and effect because statistical tests show only dependencies between different events. We can find no studies on the association relationship and correlations. Explanatory: Its purpose is to explain the behavior of a variable other function(s). Here, there is a cause-effect relationship and must meet other criteria of causation (Bradford Hill). It requires both methodological and statistical control. Predictive: Responsible for the estimated probability of adverse events generally, such as complications of the disease, mortality, etc. The line of research must have previously passed by the other levels. Applicative: Poses solve everyday problems or to manage practical situations. It can be programmatic or program, so that part to technical innovation, craft and industrial as properly scientific. Description: Describe is to explain, in detail, orderly, how are the people, places or objects.
Variables
Variable: Any event susceptible of being measured.
Independent Variable: That whose existence is independent, not dependent on another; rather, it depends on others. It represents the factors that constitute the cause and has been shown previously to be a risk factor for the problem under study. Variables in this system arise only as independent variables.
Dependent Variable: In this set of variables, it represents the variable of interest or study variable. Its existence and development depend on another independent variable; its mode of being is conditioned by other aspects of reality. It is the measuring or describing of the problem under study.
Variables: It is reflected in the variable dependiente.Hay three types:
Confounding Variable: Your participation can enhance or antagonize the apparent relationship between the problem and a possible cause, creating confusion in the research. His influence is evident both on the independent variable as the dependent variable. Their control should be performed using stratified analysis.
Intermediary Variable: The variable appears in countless ways during an observation or unexpectedly in an experiment between the causal factor and effect. Occurs when there has been a good choice of risk factors. The most suitable for neutralizing their participation is the multivariate analysis.
Control Variable: A variable with a strong influence on the dependent variable but no known effect on the independent variable. Participation is usually recognized at the time of planning. His control is carried out methodically by the exclusion criteria.