by Arlene Minkiewicz
| September 19, 2014
Which came first the chicken or the egg? We can look to Darwin for one theory, the Bible for another but at the end of the day – nobody really knows. There can be no chicken without an egg, nor there be an egg with no chicken. Thus we are left with a bit of a circuitous conundrum.
Joint Confidence Level (JCL), NASA’s current best practice for program planning and management, also presents a circuitous conundrum. When a program has a JCL of 70% this implies that there is a 70% confidence that the cost will be at or under X$ and the program will be completed at or before Y months. Much time and effort has been invested in developing methods for performing JCL using lots of different mathematical and statistical processes. But many of these methods and techniques ignore a rather important aspect of cost and schedule estimating – schedule drives cost and cost drives schedule.
This fact does not make JCL analysis impossible. It merely means that cost and schedule risk analysis cannot be performed in vacuums. Rather than calculating a JCL we should be trying to converge on cost/schedule pairs that meet specific JCL requirements.
Next week I will be attending the 2010 NASA Cost Symposium in Kansas City, MO. Because JCL is such a hot topic with the NASA cost community, nearly half the program, including my own talk, is devoted to this topic. Lots of great work is being done in this areas. I encourage anyone with interest to attend if they can or follow up with conference materials when they become available later this month.