Average grading system

[stevestamp]

Hello,


My job uses an average grading system based to measure performance.
All employee production is added together at the end of the month and averaged by the number of employees.

If you have above average production compared to the rest of the group, you receive a good grade.
If you have below average production compare to the group, you receive a bad grade.

Receiving too many bad grades could result in loss of employment.


The problem with an average based grading system is that we all have different shifts.
Some shifts are high yielding and others are low yielding. If you are stuck receiving only low yielding shifts, its impossible for you to receive a good grade being compared to people with high yielding shifts.




EXAMPLE CHART -
Does not accurately depict the difference in yield. Many people rotate between high-med-low shifts throughout the week while others receive mostly high or low.

Max potential peaks
High Yield Shift	150 per hour
Med Yield Shift	90 per hour		Employee	Day 1	Day 2	Day 3	Day 4	Day 5
Low Yield Shift	70 per hour	High Yield Shifts	Uw 1	150	150	150	150	150
			Uw 2	150	150	150	150	150
			Uw 3	150	150	150	150	150
		Med Yield Shiefts	Uw 4	90	90	90	90	90
			Uw 5	90	90	90	90	90
			Uw 6	90	90	90	90	90
		Low Yield Shifts	Uw 7	70	70	70	70	70
			Uw 8	70	70	70	70	70
			Uw 9	70	70	70	70	70
			Uw 10	70	70	70	70	70
		Total Decisions		1000	1000	1000	1000	1000

	Target needed	Actual	Wasted	Short
	500	750	250
	500	750	250
	500	750	250
	500	450		-50
	500	450		-50
	500	450		-50
	500	350		-150
	500	350		-150
	500	350		-150
	500	350		-150
			750	-750
Average	500	500
Average per day	100	100

I'm stuck on creating an alternate method of grading. I've considered weighted averages however the shift yield/production are variable and change every shift and I wouldn't know what to assign as the proper weight.
The only thing that is known is that early mornings and late evenings always produce the highest yield ~ 30% more than mid day shifts.
Different days of the week yield higher amounts than others as well.. for example a monday yields ~ 30% more than a tuesday.


Unfortunately the current grading system most accurately measures timing (what days/ hours you work your shift) than it does skill or effort.

I am searching for a grading solution that focuses more on measuring skill and effort





Thank you in advance for any insight!!

 

[lev888]

How about this approach? Keep running averages for Low, Med, High shifts. Not sure about the time period for the average (daily, weekly, monthly?). When recording daily numbers for grading, calculate the 2 factors, l and m: Low*l=High, Med*m=High. Then scale all low shift numbers by l and med shift numbers by m.