MEASUREMENT -IN EDUCATION

MEASUREMENT
Wiersman and Jurs (1985),define measurement as a process of assigning numbers of numerals to object or events according to rules .The numbers represents some specific characteristic of the object or event. A numeral can be a symbol such as 1, 2, 3, 4 etc. However the numeral itself has no relevance to measurement until it is assigned quantitative meaning.
Babyegea (1998) defines measurement to be a process of obtaining and assigning numerical description of the degree to which an individual processes a particular characteristics. In teaching and learning process measurement  involves scoring  the test and giving a student a score or a mark he/she has obtained e.g Assigning 60 to a particular student is what makes testing to be a measuring  process.
SCALES OF MEASUREMENT
(i).Nominal measurement scale
In this case, numbers has got no meaning rather  they are used for identification and categorization process of objects or attributes. Eg In soccer- players are being given numbers in order to be identified like
1-      Goalkeeper
2-      First basemen
3-      Second basemen
N.B The numbers do not mean anything, the assignment in arbitrary (arbitrary means that zero does not indicate the complete absence of property), and no arithmetic of these numbers in meaningful e.g One plus two  does not equal to three since first  player plus the second does not lead to the third player. Therefore nominal numbers are used for identification purposes.
(ii). Ordinal scale
Is a scale used for classifying and assigning rank order. Eg ranking individuals in a class according to their test scores. Student scores could be ordered from first, second, third and so forth to the lowest score.
Advantages
a)Gives more information than nominal  measurement.
Disadvantages
(a)The units of ordinal scale are most likely unequal- the difference between the first person and the second and the third does not necessarily vary equally. The number of points separating the first and the second students probably not be equal to the number separating the fifth and sixth students.
(b)No mathematical operation can be performed through this scale since addition and subtraction of such units yield meaningless numbers. This is because the interval between numbers is unknown, depends on performance. One can be the first if is the only one getting 30 or 50or 70 or100.
(iii). Interval scale/Equal interval/Equal unit Measurement.
The interval between two values is fixed or is in equal means. The scale contains properties from nominal and ordinal scale. E.g Thermometers and calendar years. The difference in temperature between 10 and 20 is the same as that between 47 and 57degrees centigrade. Likewise the difference in length of time between 1946 and 1948 equals to that between 1973 and 1975. These measures are defined in terms of physical properties such that these intervals are equal.
Advantages
(a)Some mathematical oparations can be performed e.g Addition and subtraction.
Disadvantages
(a)We cannot  multiply or divide because we do not know  the absolute upper and lower limits. E.g Temperature 0 does not mean that there is no temperature, 100 in Math does not mean that one has all abilities in math.
(iv).Ratio scale
The scale is used for measuring height, volume, weight, distance etc. it is rarely used and achieved in educational assessment either in cognitive or affective areas. This is because; unlike in an interval scale in the ratio scale, zero point  is not arbitrary. A score indicates the absence of the quality being measured.
Advantages
a)Allows comparison E.g  Asha is ½  times as taller as her young sister Anna. However we can seldom say that one’s intelligence or achievement is ½ times as greater as that of another person.
SUMMARY
Nominal Scales: categorize and order
Ordinal scales: Categorize and order
Interval Scales: Categorize, order and establish and equal unit in the scale
Ratio Scale: Categorize order, establish and equal unit  and contain a true zero point.
N.B: Educational testing falls usually somewhere between Ordinal and Interval scales in sophistication.
              FUNCTIONS OF MEASUREMENT IN EDUCATION
Educational measurement saves specific functions. These functions can be grouped under 3 general categories, INSTRUCTIONAL, GUIDANCE and COUNCELLING, ADMINISTRATIVE PURPOSES.
INSTRUCTIONAL
(i)Motivate and enhance learning to students. An appropriate and fair test enhances students’ morale to learn while unfair one discourages them, so as teachers we need to be very careful when constructing a test.
(ii)Test provide feedback to the teacher on the nature of the students. The results may be used for diagnosis of possible student’s weakness and evaluation of student’s performance.
(iii)Provide feedback on the effectiveness of instruction (teaching and learning process)
Has the instruction been effective?
§  Is there certain content that was poorly covered?
§  Student’s misconception due to confused instruction? (for improvement to be made)
GUIDANCE AND COUNCELLING
(I)Students can be guided on how to study depending on the frequency of their scores.
ADMINSTRATIVELY
(II)Measurement can save a function of correcting administrative issues often related to program evaluation. Test information indicates weather or not student needs are being met. In some schools, school boards use student’s test results for the evaluation of the teaching performance or sorting students in streams e.g  stream A- Intelligent, B- Moderate etc. administratively decisions can be easily made from test results.
EVALUATION (Answers the questions how good?)
     Is a systematic process of observing, collecting, analyzing and interpreting information to determine the extent to which students are achieving what the teacher intends them to achieve. Teacher’s intentions are normally expressed as instructional objectives. Generally evaluation deals with value judgment on the entire process of testing, measuring and evaluating the desirability of the results.
N.B Evaluation does not always base on measurement, sometimes can base on information acquired from non measurement techniques like observation.
REFERENCES
Babyegeye  E.B.,(1998).Test and measurements .The open university of Tanzania .Dar es salaam.
Ebel  R.L., and Frisbie,D.A (1991).Essentials of Educational Measurement .New York :Prentice Hall.
Gronlund ,N.E and Linn ,R.L (1990),Measurement and Evaluation  in Teaching.N.Y.Macmillan.
Omary ,I.M.(1995).Conceptualizing Quality in Primary Education .papers in Education and Development,16,25-48.
Thorndike ,R.L,and Hagen, E.P.,(1991) .Measurements and Evaluation in psychology and Education :New York .Macmillan.
Tyler,E.E.,(1964).Test and Measurements New Jersey .Prentice Hall.
Wiersma, W. and Jurs .S.G, (1985).Educational Measurement and Testing .Allyn and Bacon ,Inc.USA