Aggregate KPI for time and performance
I have a project KPI that I can measure daily: the use of a bottleneck resource, measured as the % against a target value of hours of use.
- day_1: 100%
- day_2: 95%
- day_3: 95%
- day_4: 95%
- day_5: 95%
- day_1: 100%
- day_2: 100%
- day_3: 100%
- day_4: 10%
- day_5: 10%
The goal for this KPI is to accomplish 100% of use on a daily basis.
Week_1 was not very successful (1/5) in terms of "complete accomplishment of 100% use", but each day was very close to the 100% goal.
Week_2 was somehow successful (3/5) in terms of "complete accomplishment of 100% use", but the bad days were very far from the goal.
Now I want to summarize the week with one single metric, and I want it to be fair and informative.
If the weekly summary metric is something like the number of days when the 100% goal was accomplished (1/5=20% and 3/5=60% in the previous examples), I don't know if it is fair, but it is not very informative.
If the weekly summary metric is the average of the daily scores (96% for Week_1 and 64% for Week_2 in the previous examples), it is probably not fair and not informative.
What would be the best way to build a metric to summarize the week?
Notwithstanding that I am not sure what you are measuring, try reading the data cumulatively. For example, assuming 100% means the completion of 100 units, by the end of the first week, you should have completed 500 units. Using the percentages you provided, this means you did complete 480 cumulatively, or 96% (the same as the weekly average as you posted above). However, assuming week two's work is related to week one, you would have completed 800 units of the 1,000 planned units, or 80%. This accurately measures performance and is the same way, essentially, of how you measure using earned value and earned schedule. To interpret it, you are at day 8 from a performance perspective while your actual time is day 10. To predict the number of days you'll need to finish the last 200 units based on current performance, you take 10 (number of planned days) and divide it by your performance of 80% (10/80%) and you get 12.5. So you need 2.5 more days to complete.
You did experience a sudden drop off in performance, however, and, if that prevails, the 2.5 more days won't come true. You need to perform at 80% to achieve 12.5. If you can perform at 100% of performance levels, you can finish in 12.