What is on standard efficiency & how to calculate.

• What is On-standard efficiency and overall efficiency?
• How to calculate on-standard efficiency and overall efficiency?
• What are the differences between these two efficiency terms?

Workers performance and production line performance is measured in efficiency. 

Efficiency Calculation formula 

 Efficiency (%) = (Total minutes produced / Total minutes attended at work)*100 

In a normal workday, operators spend their total attended time following categories

1. doing standard work
2. doing off-standard work (doing a task which is not familiar to the operator / other than a regular job)
3. doing nothing (lost-time like power failure, machine breakdown, no feeding/no work)

When an operator works on a bundle (garment pieces) they produce standard minutes whether she works on-standard operation or an off-standard operation. But when an operator does nothing but sitting idle due to some reasons is lost time.

If an operator does not get work, that is not her fault. In such cases, if you measure her performance considering all the attended hours, that will reflect a wrong performance. For this reason, on-standard efficiency is measured where only on-standard work hours are considered for calculating efficiency.

Measuring on-standard efficiency is good for operator skill analysis but when it comes for production at the end of the day, or line efficiency, and incentive calculation for the line and individual operator, overall efficiency is used for eligibility level.

How to calculate on-standard efficiency, off-standard efficiency and overall Efficiency

To measure on-standard efficiency, off-standard efficiency and overall Efficiency we need to collect the following data

(A) Total hours worked on the standard work
(B) Standard minutes produced while working on standard work
(C) Total hours worked on off-standard work
(D) Standard minutes produced while working on the off-standard work
(E) Total lost time in hours
(F) During lost-time, practically, no garment will be produced, so no produced minute for lost time hours.

The standard produced minute is calculated as operation SAM x Number of pieces stitched.

On-standard Efficiency (%) = (Total on-standard minute produced *100)/(Total on-standard hours worked * 60) = (B*100)/60*A)

Off-standard Efficiency (%)= (Total  off-standard minute produced *100)/(Total off-standard hours worked * 60) = (D*100)/60*C) 

Overall Efficiency (%) = (B+D)*100/(60*(A+C+E))

If there is no lost time and no off-standard work hours employee's on-standard efficiency and overall efficiency will be the same.

If there is lost time, overall efficiency will be less than the on-standard efficiency.