We introduce here a landscape changing JCL equation that mathematically compensates for the optimism bias inherently present in NASA cost estimating activity. It is called the Joint Confidence Level - Probabilistic Calculator (JCL-PC) and will correct the overly optimistic cost and schedule estimates that have long plagued the NASA cost estimating community
Thanks for the link, interesting stuff indeed.The latest SLS estimates (21 years & $38B) do seem so much larger that it might be due to a more honest estimation than previously.
And they're all going to end up with nothing at all if someone doesn't start using some common sense pretty soon.The uber-SLS as it looks today, is just plain UNAFFORDABLE on the current budget, let alone a reduced one.A program that costs too much, at a time the budgets are being reduced. Hmmm. What happens next? These are supposed to be rocket scientists. If they're really having this much difficulty figuring this simple K-12 math problem out, perhaps it *IS* time for NASA to get out of the game and make way for the people who are making real progress (as opposed to PowerPoint Progress) in this industry.Ross.
Personally, I would love to see NASA do a COTS-SHLV for 2 LV. Do up to $10 billion/ <7 years each for development, 150 tonnes to LEO, and no more than $.5B to launch. keep in mind that this is not NASA's vehicle. This is the senates. But it makes sense for us to have 2 vehicles of similar size.
Quote from: grr on 08/11/2011 04:03 amPersonally, I would love to see NASA do a COTS-SHLV for 2 LV. Do up to $10 billion/ <7 years each for development, 150 tonnes to LEO, and no more than $.5B to launch. keep in mind that this is not NASA's vehicle. This is the senates. But it makes sense for us to have 2 vehicles of similar size.But there isn't even a market for *one* 150 mT LV, never mind two. Personally I think the 50-70 mT would be optimal for the affordability and capability perspectives. The solar system would be open to us even if we never got a bigger launcher.
This problem of consistently over-optimistic schedule and budget estimates is not limited to NASA. Boeing has also been guilty of it. And so has SpaceX (and we've developed the "SpaceX multiplier" for estimating schedule, semi-jokingly). It's all over aerospace.
Quote from: Robotbeat on 08/11/2011 04:53 amThis problem of consistently over-optimistic schedule and budget estimates is not limited to NASA. Boeing has also been guilty of it. And so has SpaceX (and we've developed the "SpaceX multiplier" for estimating schedule, semi-jokingly). It's all over aerospace.Its a problem that the real world is not going to allow for much longer. In case folks in the Aerospace sector have not noticed, the world economy is not only shrinking, it is on the verge of collapse. There is a rather disturbing possibility that the European Union may dissolve entirely, the Euro and the Dollar are reaching their breaking point, and people are still getting laid off and no one is getting hired.
the European Union may dissolve entirely
It is found with overwhelming statistical significance that cost underestimation and overrun cannot be explained by error and seems to be best explained by strategic misrepresentation, namely lying, with a view to getting projects started.
Here's a paper written for the 2009 Cost Estimating Symposium: http://science.ksc.nasa.gov/shuttle/nexgen/Nexgen_Downloads/Butts_NASA's_Joint_Cost-Schedule_Paradox_-_A_History_of_Denial.pdf
Where in this presentation does it even mention SLS?
Don't be so sure about that. Thank goodness the UK didn't become part of those United States of Europe.Where in this presentation does it even mention SLS?
We introduce here a landscape changing JCL equation that mathematically compensates for the optimism bias inherently present in NASA cost estimating activity. It is called the Joint Confidence Level - Probabilistic Calculator (JCL-PC) and will correct the overly optimistic cost and schedule estimates that have long plagued the NASA cost estimating community.
The Probabilistic Calculator will attempt to correct the overly optimistic cost and schedule estimates that have long plagued the NASA cost estimating community. It will do this by applying a series of weighted factors to the several aspects of the estimate in question. The proponents of the estimate will have the opportunity to respond to these factors, and to have the JCL-PC run again, in order to partially validate or partially refute the underlying assumptions of the estimate.
Quote from: Justin Space on 08/11/2011 08:44 amDon't be so sure about that. Thank goodness the UK didn't become part of those United States of Europe.Where in this presentation does it even mention SLS?This paper was written in 2009, when CxP was still in progress.It's about large organisations *consistent* inability to realistically cost and schedule large projects with examples from NASA (like the Shuttle) and Boeing and (possibly) how to compensate for this bias.NASA is a large organisation.SLS is a large project.What are the chances NASA's cost/schedule prediction would be any more accurate this time?
The desperation to associate negativity with SLS is very telling.