Chapter 8 — Human factors and cyber policy: failure modes
Lesson map
Lesson 08 published. Map, example, EX029.
flowchart TD
N0["Learning outcomes"]
N1["8.1 Failure modes"]
N2["8.2 Slips, lapses, mistakes"]
N3["8.3 Matching defences"]
N4["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4
N4 --> EX["Worked example"]
EX --> Q["Exercise EX029"]
Logical drawing
flowchart LR
N0["Learning outcomes"]
N1["8.1 Failure modes"]
N2["8.2 Slips, lapses, mistakes"]
N3["8.3 Matching defences"]
N4["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4 --> Q["EX029"]
[Learning outcomes]
|
v
[8.1 Failure modes]
|
v
[8.2 Slips, lapses, mistakes]
|
v
[8.3 Matching defences]
|
v
[Synthesis]
|
v
[Worked example] --> [Exercise EX029]
Learning outcomes
You will (1) identify human-related failure modes; (2) distinguish slips, lapses and mistakes; (3) match defences to failure types.
8.1 Failure modes
Priya lists ways the human side of security can fail at Kestrel: a dispatcher clicks a link in a fake carrier email; a driver follows a fake text to a fake login page; an accounts clerk changes a customer's bank details after a convincing email; a supervisor forgets to tell IT about a suspicious call. Each failure has different causes. Listing failures before they happen lets the team design defences in advance rather than reacting after damage. Supervisors add two more.
8.2 Slips, lapses, mistakes
Reason (1990) distinguished slips, where an action goes wrong despite a correct plan, such as clicking the wrong button; lapses, where something is forgotten, such as not passing on a report; and mistakes, where the plan itself is wrong, such as believing a fake email is genuine. Priya classifies each failure mode. The supervisor's forgotten report is a lapse; the bank detail change is a mistake caused by deception. The classification guides the choice of defence. She explains the terms to supervisors.
8.3 Matching defences
Slips are reduced by design, such as confirmation steps for risky actions. Lapses are reduced by removing memory demands, such as a report button that sends directly to IT instead of through supervisors. Mistakes caused by deception are reduced by verification procedures that do not depend on judging appearance, such as calling the customer on a known number. Priya presents a table matching each failure to a defence type, which shows managers that more training is not the answer to every failure.
Worked example
Priya lists four failure modes, classifies them using Reason's slips, lapses and mistakes and matches each to a defence type.
Synthetic case. Failures are synthetic; Reason (1990) is real.
Errors and limits
Classifications overlap. Defences have side effects.
Exercises
- EX029 — Lapse example. Which failure is a lapse? Rubric: 3 = the supervisor forgetting to tell IT;; 2 = forgetting;; 1 = the bank change;; 0 = none.
- EX030 — Mistake definition. What is a mistake in Reason's terms? Rubric: 3 = the plan itself is wrong;; 2 = wrong plan;; 1 = wrong action;; 0 = none.
- EX031 — Lapse defence. How are lapses reduced? Rubric: 3 = by removing memory demands;; 2 = memory;; 1 = training;; 0 = none.
- EX032 — Deception defence. What reduces mistakes caused by deception? Rubric: 3 = verification not based on appearance;; 2 = callbacks;; 1 = vague;; 0 = none.
Synthesis
Classifying human failures points to defences that fit, beyond more training.
Continue studying — chapter 08 of 18
← Chapter 07 (draft) · Course chapter index · Chapter 09 (draft) →