The value of the two step risk analysis is in the following manner
Step 1 We undertake an analysis of the risks that exist in the design of the device per se, without any risk reduction. This step will also include some risks that may be introduced by the production process.
Step 1a We undertake measures to reduce risks identified in Step 1
Step 2 We undertake an assessment of the risks that remain or are introduced by the risk reduction measures introduced in the design and/or the production process.
These steps are important so as to have a logical and sequential process to conduct a detailed analysis.
Illustratively, a ground is introduced as a measure to reduce risk of shock in the first process. Hence we introduced a ground to mitigate this risk. In the second round, we have a new risk in that the ground can become defective, and we dealing with very high voltages, then we need to adopt secondary measures to reduce the risk of shock further. Please note we are now dealing with a different kind of risk than that in the first step. The risk in the first step was risk of electrical shock. In the second step, we are dealing with the risk of failure of the risk mitigation effort adopted as a consequence of analysis of step 1.
I have given a simplistic perspective.
The two step can give rise to the development of new class of medical devices, and can create new business opportunities. Illustratively, the Drug Eluting Stent.
The industry first introduced Bare Metal stents to treat blockages, but these resulted in the development of restonesis. Drug Eluting Stents were introduced to treat such residual risk.
May I add that residual risks are of two kinds
1. Risks that have not been eliminated by the risk mitigation efforts. These are allowed to remain based on the risk benefit analysis. The risk matrix in the second step will reference this risk benefit analysis.
2. Risks that are introduced as a result of the risk mitigation exercise. It is this kind of risk that is to be eliminated by the second step.