Knowing the staffs capacity for work is critical to forecasting cost and schedule. We have a working example taking place at our house. In Colorado, the landscaping has river rock around the house to move the snow melt away from the foundation. Over time, dirt fills in between the rocks, weeds grow and it's an endless battle to pull weeds, spray Round Up, and generally keep it clean.
Taking all the rocks out, replacing the cloth barrier under the rocks with new weed proof barrier, cleaning the rock, and putting then back is a job to be done every 10 years or so. We've waited 15.
The neighborhood landscaping crew - high school boys - are doing the work this summer. They bid a fixed price for labor, plus materials. They've built a cleaver machine to get the rocks cleaned and ready for replacement, using a power washed and a screen.
Now the capacity problem. They assumed they could get all this done before summer was over and they have to start school. They started in the front, removing rocks, cleaning, re-laying barrier, and putting the rocks back. A few weeks into this job it was clear to me that they were not going to make it at the pace they were going. So I asked a few questions:
- Guys (2 highschoolers), from the work you've done to date, how many linear feet of rock replacement have you done per period of performance? That is, how much rock are you replacing per hour, per day, per week so far?
- Do you have the measurement the rock beds around house and around the lawn perimeter - lawns are expensive things in Colorado, so much of the back yard is in wild grasses that can live on 11" of rain a year. Are these adjusted for the wide of the beds, which varies from 12" to maybe 3'
- With these two numbers - your rate of work to date and the "to go" distance - when do you think you'll be finished? Is this date on or before the start of school or the first snow?
This is the capacity for work calculation. At X feet per day, and Y feet total, minus Z feet to date, what is the completion date?
Capacity for Work
This is what the agile folks call velocity. It is a semi-calibrated work performance number. The Earned Value folks calculate the To Complete Performance Index (TCPI). This tells us the calibrated performance in terms of CPI (Cost Performance Index) and SPI (Schedule Performance Index) we need to maintain to complete on time. Earned Schedule has its own version of a performance index.
Many failed projects in the IT world we work have no idea of their capacity for work. They work at the rate they work.
Hope is their current strategy - We hope to get done by the start of school
Hope is NOT a Strategy. Measurement of physical percent complete of the work performed on the day is was planned to be complete at the cost it was planned to be completes is the only way to forecast the future performance of the project.
If you don't know your capacity for work, you can't know when you will be done or how much it will cost. No matter what the schedule and budget plans says.
