Sub units of Basics of Assessment
1. Measurement
BASICS OF ASSESSMENT
Measurement is a set of rules for assigning numbers to represent objects, traits, attributes or behaviours.Measurement is to find a number that shows the amount of something. A measurement unit is a standard quantity used to express a physical quantity. Measurement is a process of determining how large or small a physical quantity is as compared to a basic reference quantity of the same kind. In our daily lives, we use different forms of measurement at home, work and in other day to day activities. While cooking a cup of coffee, we have to add water, milk coffee powder and sugar in proper amount by measuring with the help of certain measuring instruments. For that we are using different measuring instruments. We cannot exist without measurement, we have to measure physical properties like length, weight, temperature, pressure, volume, time, size, distance, speed, energay etc. for which humans have developed accurate measures. In the physical sciences measurement is the activity of obtaining and comparing physical quantities of real-world object and events by using scientific devices. In physical measurement, various measuring equipment are needed and measurement is very accurate. A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other quantity of that kind can be expressed as a multiple of the unit of measurement. For example, a length is a physical quantity. The metre is a unit of length that represents a definite predetermined length. When we say 10 meters, we actually mean 10 times the definite predetermined length called "metre". Measurement is a process of determining how large or small a physical quantity is as compared to a basic reference quantity of the same kind. Physical measurement is the measurement of the object which has absolute existence, accurate and quantitative, and there are some set of tools for physical measurement all over the world.
Measurement in behavioural sciences comprises the measurement of mental processes, traits, habits, tendencies etc. mental measurement there is no surety of the accuracy measuring devices in terms of quantitative measures in the form of marks or grades. Examine the example, Hans height is 160cm and his score in Mathematics achievement test is 100. Here the data regarding the relevant measurements of a child’s physical and mental measurements are given in precise quantitative terms. Height is a physical quantity and hence it is measured with help of a scientific instrument and measurement is given in meters and this measurement is very precise, accurate and scientific. While his score in Mathematics is measured with the help of an achievement test prepared by the teacher for her classroom assessment and hence it is subject.
Measurement refers to the process by which the attributes or dimensions of some physical object are determined. When used in the context of learning, it would refer to applying a standard scale or measuring device to an object, series of objects, events or conditions, according to practices accepted by those who are skilled in the use of the device or scale.
Teaching, learning and assessment is an integrated process. A teacher normally attempts at measuring child’s scholastic and co-scholastic aspects using various tools and techniques like tests, rating scale, checklist, anecdotal records, observation, cumulative record etc. He usually represents the results of these measurements in terms quantitative measures in the form of marks or grades. This process is what we generally indicate by the term educational measurement. It is also known as mental measurement or ‘psychological measurement’. It is always relative and there is no absolute zero. For example, for measuring the intelligence of a person we have to take the help of intelligence tests which are subjective in nature. Through his response, we can know the level of intelligence of the person concerned. Mental measurement is both qualitative and quantitative in nature, and there are no fixed tools for such measurement i.e., the same set of tools may not be applied to different types of persons
1.1.1 Concept of Educational Measurement by different educationists
Measurement involves the process of quantification. Quantification indicates to what extent a particular attribute is present in a particular object. It is the act or the process of ascertaining the extent or quantity of something.
Measurement is the process by which a characteristic of an object, person or activity is perceived and understood on specific standards and is described in standard words, symbols or definite units.
Measurement is the process of quantifying observations [or descriptions] about a quality or attribute of a thing or person Thorndike and Hagen
Measurement is a process by which we assign numbers to express the quantity of an object or trait.
Measurement can be defined as a set of rules for assigning numbers to represent objects, traits, attributes or behaviours.
Measurement is the process of assigning symbols to the dimension of phenomenon in order to characterise in order to characterise the status of phenomenon as precisely as possible.
James M. BradfieldMeasurement is the assignment of numerals to objects or events according to certain rules.
J.P.GuilfordMeasurement results are some score or numerical value and quantitative descriptions of the pupils.
Norman E. Gronlund
Measurement is a process of obtaining a numerical description of the degree to which an individual possesses a particular characteristic (Answer the question How much).NE Gronlund
By analysing the above definitions, it can be said that measurement is the process of quantification of some phenomena, objects. It is to assign a number or a set of numbers to one or a setoff phenomenon. In this process comparison is made of a quantity with an appropriate scale for the purpose of determining the numerical value.
1.1.2 Characteristics of Measurement
• It is a process of:
• Quantification of something.
• Assignment of numerical value or symbols
• Comparing an unknown quantity with a known, with an appropriate scale or unit.
• Determining magnitude of a variate.
• Answers the question “how much”
1.1.3 Process of measurement
Step-1: identifying and defining the quality or attribute that is to be measured
- Some attributes or constructs can be measured directly. For example, height, weight, blood pressure etc. can be measured directly using certain instruments. In behavioural science, we usually must use more indirect ways to measure constructs, so we have to develop a number of items to assess the construct. The construct is a proposed attribute of a person that often cannot be measured directly, but can be assessed using a number of indicators or manifest variables. In psychology, a construct is a skill, attribute, or ability that is based on one or more established theories. Constructs exist in the human brain and are not directly observable. So the first step in measurement is to identifying and defining the quality, construct or attribute that is to be measured;
Step-2: Determining operations to isolate and display theattribute
The second step is to develop a procedure to find out and invent a set ofoperations which will isolate the attribute of interest and display it. That is determining a set of operations by which the attribute may be made manifest and perceivable. There areattributes like length or weight for which we can use well standardized instruments and units of measurement,but if we are measuring intelligence, or honesty or any dimension of personality, we have to determine the set of operations; this is called operationalizing the attribute or operational definition. For example, operational definition of creativity refers to the score obtained by an individual on a standardised test developed based on the Torrance theory of creativity.
Step-3: Quantifying the Attribute
The third step of the measurement process is establishing a set of procedures or definitions for translating observations into quantitative statements of degree or amount. That isassigning numerals to quantify the aspect of measurement or the attribute. This quantification helps incommunicating about the attribute more efficiently and precisely. If quantificationhas been done according to a set of rule (this is known as scale), we canapply mathematical operations for making the measurement more meaningful.
For example, heights can be measured in centimetres or inches, interest can be measured using rating scale.
1.1.4 Scales of Measurement
A scale is a system or scheme for assigning values or scores to the characteristic being measured (Sattler 1992). There are four scales of measurement, and these different scales have distinct properties and convey unique types of information. The four scales of measurement are nominal, ordinal, interval and ratio scale.
Nominal scale
Nominal scales are the simples of the four scales. It provides a qualitative system for categorizing people or objects into categories, classes or sets. For example, gender is an example of a nominal scale that assigns individuals to mutually exclusive categories.This isascale of measurement in which the scale values represent categories that only differ from one another qualitatively (i.e., differ in “type” rather than in “amount”). In other words, the different values of a variable are categories that only represent different “types” of something. Variables measured using a nominal scale are also known as "qualitative" variables.
Ordinal scale
Ordinal scale measurement we can rank people or objects according to the amount or quantity of a characteristic they display or possess. Hence ordinal scale enables us to quantify the variables under examination. A scale of measurement in which the scale values represent categories that differ quantitatively in terms of their order, but in which the intervals between numbers (i.e., between categories) cannot be assumed to be equal.Ordinal indicates “order”. Ordinal data is quantitative data which have naturally occurring orders and the difference between is unknown. It can be named, grouped and also ranked. For example, ranking the children in a classroom according to their height from the tallest to shortest.
Interval scale
An interval scale is one where there is order and the difference between two values is meaningful. A scale of measurement in which the distance between any two adjacent scores is the same as the distance between any other two adjacent scores. However, there is no “true” or “natural” zero point and therefore meaningful ratios cannot be formed. In short, numbers are spread across equal intervals without a natural zero point. which is measured along a scale, in which each point is placed at equal distance from one another. Interval data always appears in the form of numbers or numerical values where the distance between the two points is standardized and equal.Interval data cannot be multiplied or divided, however, it can be added or subtracted. Interval data is measured on an interval scale.
Ratio scale
Ratio scales have the properties of interval scale plus a true zero point that reflects the complete absence of the characteristic being measured. With ratio scales, the scale values are numbers that represent equal distances in some attribute, and there also is an absolute zero point. This is a unique feature of ratio scale. Thus, meaningful ratios can be formed. It is a type of variable measurement scale which is quantitative in nature. It allows any researcher to compare the intervals or differences. For examples, height measured in inches, which is a ratio scale, you may properly say that somebody 60 inches tall is twice as tall as somebody 30 inches tall.