What is Rating in Industrial Engineering?
Different workers perform their job with different efficiencies. Some workers are clever; they learn their job quickly and attain a very high efficiency. Some others may be mediocre and many others may be lenient to learn or may be dull. Thus workers widely vary in their performance. Thus rating is the measure of speed with which an operator works. Rating is the speed of an operator doing a job relative to the observer’s idea of standard pace of work. Rating is thus a comparison of the rate of work observed by a work study executive with the idea of some standard level of working in his mind.
How Work Study Officer Uses Performance Rating in Readymade Garments Industry?
Rating an operator is usually a very difficult task. It requires long experience in the floor, patience, intelligence, etc. If the work study executive thinks that the operation is being performed at a rate less than standard, a factor less than 100, say, 75 will be used. If he considers that the rate of doing it is above standard, he will use a factor greater than 100, Say, 110 or l15 or 120, etc. Ratings are used as a multiple of 5. For example, a rate of 77 is never used. It is generally rounded to 80.
Basic Time and Standard Time are always constant:
Three operators are doing the same job. Their ratings are respectively the following: 75, 100 &120.
|
Operator |
Observed Time |
Operator Rating |
Basic Time |
|
Julie |
16” sec |
75% |
16 × 75% = |
|
Jesmin |
12” sec |
100% |
12 × 100% = |
|
Kariman |
10” sec |
120% |
12 × 120% = |
Thus whatever may be the rating of different operators for the same job, the basic time of that operation will be the same. In this way, Standard time of any operation is also constant irrespective of different rating of operators for the same operation & if allowance time for the whole floor is the same, say, 20%.
Example-1:
An operator was found to have 900 seconds to complete 300 pcs of her work as observed by a work-study officer. Calculate her observed time.
Answer:
Her average observed time =900 sec /300 =3 seconds.
Example-2:
The same operator was found to have a rating of 90 %. Calculate her Basic Time.
Answer:
Basic Time =Observed time X rating =3″ x 90%=3″ x 0.90 – 2.7″
Example-3:
The same operator was allowed to have an allowance time @ 20 %. Calculate her Standard time
Answer:
Standard time = Basic Time +Allowance Time = 2.7 “+ 20%
=2.7 “+ 2.7” x 20%
=2.7″ +0.54″=3.24″
Thus Standard time of the operation is 3.24″
Excercise-1:
A top center operator is found to take 540 seconds to complete a bundle of 20 jobs. Her rating was 20%. Calculate average Observed Time & Standard time.
Excercise-2:
A pocket attach operator is found to take an observed time of 35 seconds to complete her Jobs. Her rating was 100 % and allowance time was 15 %. Calculate Standard time.
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Rating is very subjective depends upon the understaanding of the job profile by the Work study Officer. And the average rating is better as the phase of the worker may change. As per the ILO manual the rating is defined, but it is bound to vary and is always subjective.