Risk in SCRUM vs. risk in Waterfall

Last post 08:08 am February 24, 2014
by Bhuvan Misra
3 replies
06:01 am February 24, 2014

Hi, in materials for PSPO 1 course, there is a picture showing how risk changes over time in SCRUM and Waterfall. I am not sure if I am understand it correctly, because i think that risk in Waterfall increases over time, not decreases. Could you tell me how to interpret this drawing? Thanks :) [IMAGE:26][THUMBNAIL:27:26] (Red is waterfall, green is SCRUM)

06:20 am February 24, 2014

I think this chart might be showing the risk of not delivering a satisfactory system at all. This is not a risk that will increase over time because the system doesn't exist in the first place. You can't get worse than nothing, even with a waterfall approach.

A waterfall process will reduce the risk of non-delivery only gradually. You can expect a big release at the end, which is where most of the risk ends up being mitigated. That's what the red line shows.

An agile process will reduce the risk incrementally with a view to mitigating it as quickly as possible. That's what the greenish-yellow line shows.

Assuming I'm interpreting the chart correctly, the really important thing to get out of it is the surface area below each of the two curves. That's the total risk exposure, and it's less in an agile way of working than it is in waterfall.

06:35 am February 24, 2014

Hi Ian, thanks a lot for your reply. The intention behind this picture looks more clearly for me right now :)

08:07 am February 24, 2014

I'm not sure if my response is completely relevant. Let me post it anyways :-)

“Cone of Uncertainty” can be better dealt with Agile than with Waterfall. The impact of any Uncertainty is contained and discovered sooner than later in the Agile/Scrum world.