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CHAPTER 10

The BXM Method

Abstract
The methodology presented in this book is called BXM. The BXM method is compliant with ISO
14971. The basic premise of the BXM method is to decompose the System; do risk analysis on the
parts of the System; and then integrate the underlying analyses into the System-level analysis. This
offers the ability to use parallel work streams, optimize labor and skills usage, and reuse analyses.

Keywords: BXM method; quantitative risk estimation; software-assisted automation

The methodology presented in this book is called BXM. The BXM method is com-
pliant with ISO 14971 [3,7]. The basic premise of the BXM method is to decompose
the System; do risk analysis on the parts of the System; and then integrate the under-
lying analyses into the System-level analysis.
There are multiple benefits to the BXM method:
1. It allows decomposing a complex System into several simpler parts which are
easier to understand, and less prone to errors of omission or commission
during the analysis.
2. It allows parallel work streams where different teams can be simultaneously ana-
lyzing the different System components.
3. It enables the management to assign people with relevant skills to the appropri-
ate teams. For example, during analysis of a mechanical component of the
System, electrical engineers would not be required to attend, as they would not
add significant value to that analysis.
4. Modularity and reuse. If a particular component is used in multiple Systems, or
even different generations of the same System, the analysis of that component
can be reused.
In the following sections the BXM method is elaborated.

10.1 SYSTEM DECOMPOSITION
Let’s say that at the top-level the System is called Level-1 (L1). In the example in
Fig. 10.1 the L1 System is decomposed into two Level-2 (L2) components. Each L2
component is further decomposed into multiple L3 components and so on. This
decomposition follows the System architecture.

Safety Risk Management for Medical Devices r 2018 Elsevier Ltd.
DOI: https://doi.org/10.1016/B978-0-12-813098-8.00010-6 All rights reserved. 45