One of the most incredible things about SDPM is its ability to give a quick index for checking performance of projects. Differently of what you get in EVM (Earned Value Management), SDPM indexes give you trends based in what is about to happen, not what has happened so far. This means that it "checks the future" to help you understand it. It is not based in what has just happened (as EVM would do). The Success Probability Index (SPIx) can be set for different things, such as: teams, machinery, materials, costs, profit or time. Making the story short, let's imagine a project that should do 100 units in 100 days for 100 "moneys". We are in day 50 and we have 40 units that have cost 60 "moneys". We then would have: SPI - Schedule Performance Index (EVM) = 0,8 CPI - Cost Performance Index (EVM) = 0,66 With Earned Value Management, we would check the past trends to imagine what will happen in the future. It doesn't matter if for day 51 to day 100 we schedule a complete new set of resources and goals for the project, the SPI and CPI are based only in what have happened, so it will not help project management in deciding if future plans are good enough for recovering the project. SPIx is calculated with the probability of achieving some result based in the scenarios we have. This means that for the remaining days of our example project, the probability is based in the WORK LEFT, with the TIME REMAINING and with an evaluation of the scenarios to finish it. If we include new resources, we may increase the probability index for the remaining project and therefore succeed in recovering the present situation; such probability will be calculated according to several aspects of the project: the optimistic, pessimistic and probable scenario, the availability of resources (materials, money, machinery, manpower) and so on. In short, with SDPM you may look at trends of what has happened, but the best of it is to verify what may happen in the future by evaluating the SPIx for the remaining work, not what has happened so far. |