Measuring Variable
The purpose of collection and summarization of data is transformed into information to identify
variables/facts, measure variables/phenomena, describe behavior and obtain empirical evidence
that ought to be objective, reliable, and valid. As stated earlier, objective means the data that is not
influenced by anyone who collects the information. Reliability refers to the consistency or constancy of
measuring instruments. Consistency means that data are collected from each subject in the study in
the same way or as close to the same way as possible. Consistency can minimize the bias
introduced when more than one person collects the data. Constancy means that the methods and
procedures of data collection are the same for all subjects. Validity refers to the determination of whether a
Measurement instrument actually measures what is purported to measure. Thus, the researcher must
consider ways to minimize subjects anxiety and to maintain their motivation to complete the data
collection process, and data collectors must be carefully trained and supervised. To ensure consistency in
data collection, researchers must rehearse data collection in the method to be used in the study so that
each person collects the information in the same way.
Measurement is central to the process of obtaining data. How and how well the measurement in
the research project is made as critical in determining whether the project will be successful.
The term 'measure' means to ascertain the dimensions, quantity, or capacity of, to mark off, usually regarding some unit of measurement. It is the assignment of numbers to object or events according
to rules. The measurement consists of rules for assigning numerical values to objects to represent
varying degrees of some attributes being measured. The purpose is to measure these attributes quantitatively.
Approaches Measurement
In conducting 'nursing research,' investigators measure many types of phenomena. To achieve an
understanding of human responses in health and illness, nurses need to study people's thoughts,
feelings, attitudes, experiences, sensations, skills, behaviors, and physiological functions. To study the
variety of phenomena, the investigators use several different approaches to measurements, including
norm-referenced measurement and criterion-referenced measurement.
Norm-referenced Approach
Norm-referenced measures are techniques appropriate for evaluating the performance of an individual
relative to some other individuals in a group. Norm-referenced measurement permits meaning to be
assigned to scores through comparing one participant's performance to the performance of others, i.e., through reference to a group norm. Norm-referenced measurements are appropriate when the investigator is interested in evaluating the performance of an individual relative to other individuals in the group. Standardized tests are
one type of norm-referenced measure. For example, the Minnesota Multiphasic Personality Inventory
(MMPI), Tennessee self-concept (TSC) Scholastic Aptitude Test (SAT), Stanford-Binet test, and Wechsler
Intelligence test of Intelligence, etc. These tests have been developed after years of testing. The
reliability and validity data are established for use with many different groups of the population.
Criterion-referenced Approach
Criterion-referenced measures are techniques appropriate for
determining whether or not an individual has acquired a set of behaviors or mastered a specific risk. These measures low the investigator to determine whether the subject has reached a certain specific performance criterion or has mastered a specific task. An either-or pass-fail approach in which a specific set of target behaviors (or items sampling a content area) is designated. When these are mastered, the subject is considered proficient in that area. This approach enjoys popularity among those charged with assessing. For example, clinical skills among nursing students.
Measurement Process
The measurement process is not difficult to understand certain measurements used in physical sciences
such as length, height, weight, but it is tough to understand the measurements of such
characteristics of individuals and groups as intelligence, aggressiveness, anxiety, and such others.
Therefore, the measurement process constitutes the operational definition of concepts, specifying the
nature of attributes and existence of phenomena under study and giving numerical expression.
As stated earlier, measurement is assigning some numerical value to objects or events to
represent the kind or amount of some characteristics of those objects or events. As used
in this context, measurement includes qualitative measurements in which objects are assigned to categories that
represent the kind characteristics they possess and that are mutually exclusive and exhaustive. So, the
measurement can be defined quantitatively and qualitatively as follows.
Qualitative Measurement
Quantitative measurement is assigning a numerical value to objects/events to represent this kind
or amount of characteristic of those objects events. The function that assigns each member of one set of
objects to some value of another set is sometimes referred to as the 'rule of correspondence.'
Measurement is
a quantitatively oriented activity that assumes that characteristics of objects or events exist in some amount. The function takes F = (X, Y), where X is any object or Y is some numerical.
The rule of correspondence determines whether the character is there and in what
quantity is present. For example, the number of admissions, discharges, and deaths in a year according to
the type of disease or condition.
Qualitative Measurement
Qualitative measurement is a process of classification that involves assigning objects to categories (i.e.
distributing phenomena into classes) that represents a variation of the concept being studied. The
characteristics of the classification system described (Kerlinger, 1986) are as follows:
- The classification system should be natural or relevant
- The set of categories should be exhaustive
- The individual categories should be mutually exclusive or disjoint • The category system should be
derived from and should develop a principle or ordering - The individual categories should be formulated on the same level of abstraction or discourse
- The classification system should be useful
- The classification system should be constructive. For example, nursing diagnosis, medical diagnosis,
age-wise classification, sex-wise classification, etc.
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