In my two latest columns, I have been reviewing the book _Managing Cyber-Security Resources: A Cost-Benefit Analysis_ by Lawrence A. Gordon & Martin P. Loeb. Today I’ll continue with a couple more of the chapters in this excellent resource for IA managers.

Chapter 2, entitled "A Cost-Benefit Framework for Cybersecurity," begins with clarification of the distinction between operating costs and capital investments - a touchy subject for a countenance because, as the authors point out, our rapidly changing technical and threat environments mean that much of what we buy has to be replaced relatively quickly.

From some standpoints, it would make much more sense to regard IA expenditures as operating expenses. The authors write, "the fact that corporate balance sheets usually do not explicitly report cyber security investments, even though such investments are critical assets for organizations operating in the digital economy, supports the observation that firms generally expense cyber security investments." They add, "Indeed, a good way to view all costs related to cybersecurity activities is to think of them as capital investments with varying time horizons."

Next, the authors define the principles of cost-benefit analysis; in essence, "the organization should keep increasing its security activities as long as the incremental benefits from increases in such activities exceed the incremental cost of those activities."

They then discuss the net present value (NPV) model, which takes into account the costs of investments over time (e.g., the costs of financing and lost investment opportunities) and values such as loss avoidance and the incremental gains associated with those benefits - all expressed in constant currency values. They explain the internal rate of return (IRR) and return on investment (ROI) and then provide detailed scenarios and calculations to help readers get used to these quantitative concepts.

Chapter 3, "The Costs and Benefits Related to Cybersecurity Breaches," explores how managers can classify and evaluate direct and indirect costs as well as explicit and implicit costs.

These two dimensions are orthogonal (independent). Direct costs can be traced to specific security incidents, whereas indirect costs include IA overhead such as firewalls and other security devices or personnel costs for IA teams. Explicit costs are those tied specifically to IA; implicit costs include consequential damages such as opportunity costs.